Category Archives: Animal Behavior

Ants eat a gecko in a little over two hours

The Behavior and Misbehavior of Dogs

From SCONC:

Tuesday, Oct. 14
6:30-8:30 pm
Science Cafe Raleigh: The Behavior and Misbehavior of Dogs
Barbara Sherman, of NC State’s College of Veterinary Medicine and president of the American College of Veterinary Behaviorists (pet whisperers) discusses dog behavior, and misbehavior. Tir Na Nog, 218 South Blount St, Raleigh

Bats eat birds – join the discussion

As the month of September is coming to a close, and the topic of the month in PLoS ONE is bats, we decided to end the focus with a Journal Club.
Starting today, and lasting a week, there will be a Journal Club on this PLoS ONE article – Bats’ Conquest of a Formidable Foraging Niche: The Myriads of Nocturnally Migrating Songbirds by Ana G. Popa-Lisseanu, Antonio Delgado-Huertas, Manuela G. Forero, Alicia Rodriguez, Raphael Arlettaz and Carlos Ibanez:

Along food chains, i.e., at different trophic levels, the most abundant taxa often represent exceptional food reservoirs, and are hence the main target of consumers and predators. The capacity of an individual consumer to opportunistically switch towards an abundant food source, for instance, a prey that suddenly becomes available in its environment, may offer such strong selective advantages that ecological innovations may appear and spread rapidly. New predator-prey relationships are likely to evolve even faster when a diet switch involves the exploitation of an unsaturated resource for which few or no other species compete. Using stable isotopes of carbon and nitrogen as dietary tracers, we provide here strong support to the controversial hypothesis that the giant noctule bat Nyctalus lasiopterus feeds on the wing upon the multitude of flying passerines during their nocturnal migratory journeys, a resource which, while showing a predictable distribution in space and time, is only seasonally available. So far, no predator had been reported to exploit this extraordinarily diverse and abundant food reservoir represented by nocturnally migrating passerines.

Folks in the The Kalcounis-Ruppell lab, Hershey lab and O’Brien lab in the Department of Biology at UNC Greensboro, have read and discussed the paper and posted their comments here.
You know what to do – go there, register/login and join the conversation.

Shimmering Bees

The PLoS ONE paper about the way shimmering wave behavior in honeybees repels hornets, as discussed by high-school students here, has an aaccompanying video of the behavior on YouTube:

A fable about the Frog and the Salamander

Bat and moth

Bats in the attic at dusk

Bats and fish eating each other

Bats, Bats, Bats!

Batman.jpgThis month’s Theme Of The Month in PLoS ONE are bats! Midway between the release of Batman II and Halloween, this sounds like an appropriate choice. Peter Binfield provides more information.
A number of our bat papers have received media and blog coverage (and not just by Anne-Marie!), but it is never too late. Bloggers tend to write about the newest papers, fresh off the presses. But nothing stops you from going back and covering one of the older papers if you find it interesting. Perhaps you were just not aware of it before.
Here are some of our bat papers to date, showcasing the diversity and quality of chiropteran research in PLoS ONE:
Accelerated FoxP2 Evolution in Echolocating Bats
Echolocating Bats Cry Out Loud to Detect Their Prey
Bats Use Magnetite to Detect the Earth’s Magnetic Field
Absent or Low Rate of Adult Neurogenesis in the Hippocampus of Bats (Chiroptera)
The Perils of Picky Eating: Dietary Breadth Is Related to Extinction Risk in Insectivorous Bats
Bats’ Conquest of a Formidable Foraging Niche: The Myriads of Nocturnally Migrating Songbirds
Bats Avoid Radar Installations: Could Electromagnetic Fields Deter Bats from Colliding with Wind Turbines?
bat.gifNutrition or Detoxification: Why Bats Visit Mineral Licks of the Amazonian Rainforest
Paracellular Absorption: A Bat Breaks the Mammal Paradigm
Evidence of Henipavirus Infection in West African Fruit Bats
Temporal Dynamics of European Bat Lyssavirus Type 1 and Survival of Myotis myotis Bats in Natural Colonies
Genomic Diversity and Evolution of the Lyssaviruses
Marburg Virus Infection Detected in a Common African Bat
As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers.
And if you work on bats, send your manuscripts to PLoS ONE. It is becoming quite a hub for bat papers and the people around them.

Flying Fox Bat fights a Python

…and wins:

Assassin Bugs and Bats

Animal Behavior

I hope you don’t faint while reading this post….

…but if you do, I hope it was enjoyable! And edifying, of course. Kind of science that is amenable to experimentation at home.

Domestication – it’s a matter of time (always is for me, that’s my ‘hammer’ for all nails)

Since this article came out in The American Scientist (the only pop-sci magazine that IMHO has not gone downhill in quality over the past decade) in early 1999 (you can read the entire thing here (pdf)) I have read it many times, I used it in teaching, I discussed it in Journal Clubs, and it is a never-ending fascination for me. Now Andrew and Greg point out there is YouTube video about the fox domestication project:

Back in the 1950s, Dmitri Konstantinovich Belyaev started an experiment in which he selectively bred Silver Foxes, very carefully, ONLY for their tameness (and “tameness” was defined very rigorously in terms of type and speed of response, distance that triggers aggression, etc.).
What happened really fast in this experiment is that many other traits showed up, seemingly out of nowhere, in the subsequent generations. They started having splotched and piebald coloration of their coats, floppy ears, white tips of their tails and paws. Their body proportions changed. They started barking. They improved on their performance in cognitive experiments. They started breeding earlier in spring, and many of them started breeding twice a year.
Most of the people reacting to this experiment invoked pleiotropy, i.e., how changes in one gene affect expression of many other genes. See this NYT article for instance. However, even while I was reading it for the first time, my mind screamed – development! And not just development, but more specifically, heterochrony – change in timing of developmental event.
If you alter the expression of one of the genes that affects developmental timing, you affect all sorts of things.
For instance, when the neural crest cells migrate they become melanocytes in the skin – if due to changes in timing they are late to arrive to some distal parts, e.g., paws and tail-tips, those part will be white. Neural crest cells also migrate to become the adrenal medulla – that little part of the body that releases (nor)epinephrine (adrenaline). If fewer of those cells arrive there on time, less the animal will show stress-response later in life.
There appears to be tight correlation between timers that act on different scales, e.g., developmental and circadian timing, circadian and fast behavioral timing, circadian and seasonal timing, etc.
I always wished I could get a lab, some foxes, an IACUC approval and some money to run these animals through a battery of standard experiments comparing dogs, wild foxes and domesticated foxes on all sorts of parameters of circadian rhythms, photoperiodism (they did change their seasonality patterns of breeding, after all), etc.
The bottom line is that a subtle change in timing of expression of a single developmental gene, something one can select for by choosing one of the traits (in this case a behavioral trait), will affect the change in timing of expression in many other genes. The difference between wild and domesticated foxes may not be in any DNA sequence at all – it could presumably be all epigenetic (see also). Sequence differences would arise later, as the two populations are not inter-mixing any more (for 60 years now).
When you put together development, genetics and evolution, you can see that big changes (or, really, any changes at the very beginning of the evolutionary change) in DNA sequence are not necessary for big changes in entire suites of phenotypic traits. But in the 1950s, the bean-bag deterministic genetics was the norm, so the Belyaev experiment was a big jolt to the scientific community in the West (not so much for the Russian evolutionary biologists, though), so we need to look at this experiment through a decent grasp of history.
Now, I’d like to know what is the state of the experiment today. Ten years ago, the project appeared doomed – they had to sell foxes for fur in order to keep going at a small scale. Has this been fixed? Has anyone from the West help finance the continuation of the project? Has anyone in the West acquired some of the foxes and continued with the project? What are the recent developments?

Fighting Giraffes

Kangaroo fight or dance

Satellite tracking turtles reveals migration secrets

Fainting Goats

Good science on the blogs these days!

Broca’s Area, 1865:

This doesn’t sound too out there to us now, but at the time it caused a lot of controversy. The problems wasn’t the localization to the inferior frontal lobe, it was Broca’s claim that it was the LEFT inferior frontal lobe. This didn’t sit well with a lot of scientists at the time. It was pretty accepted that, when you had two sides or halves of an organ, the both acted in the same way. Both kidneys do the same thing, both sides of your lungs, and both of your ovaries or testes. Your legs and arms will do essentially the same thing, though due to handedness (or footedness), you may have more strength or dexterity on one side. Therefore, if the left part of your brain was involved in language, the right must be also.

Operant and classical learning can be differentiated at the genetic level:

Learning about relationships between stimuli (i.e., classical conditioning) and learning about consequences of one’s own behavior (i.e., operant conditioning) constitute the major part of our predictive understanding of the world. Since these forms of learning were recognized as two separate types 80 years ago, a recurrent concern has been the issue of whether one biological process can account for both of them. Today, we know the anatomical structures required for successful learning in several different paradigms, e.g., operant and classical processes can be localized to different brain regions in rodents and an identified neuron in Aplysia shows opposite biophysical changes after operant and classical training, respectively. We also know to some detail the molecular mechanisms underlying some forms of learning and memory consolidation. However, it is not known whether operant and classical learning can be distinguished at the molecular level. Therefore, we investigated whether genetic manipulations could differentiate between operant and classical learning in Drosophila. We found a double dissociation of protein kinase C and adenylyl cyclase on operant and classical learning. Moreover, the two learning systems interacted hierarchically such that classical predictors were learned preferentially over operant predictors.

This food doesn’t taste right … or is it me?:

Flavor is a result of what happens with taste-receptors in the mouth (including but not exclusively those on the tongue) and with olfactory receptors. The 40 or so kinds of taste-receptors interact with the chemicals in what you’re tasting (yes, all your food is made of chemicals!) and create a nerve impulse that sends a signal to the brain. Meanwhile, the 300 or so olfactory receptors send their own smell-signal based on the volatile components of your food. The taste-signal and the smell-signal are correlated in the brain to make the flavor you’re experiencing.

Evolving snake fangs:

I keep saying this to everyone: if you want to understand the origin of novel morphological features in multicellular organisms, you have to look at their development. “Everything is the way it is because of how it got that way,” as D’Arcy Thompson said, so comprehending the ontogeny of form is absolutely critical to understanding what processes were sculpted by evolution. Now here’s a lovely piece of work that uses snake embryology to come to some interesting conclusions about how venomous fangs evolved.

The Evolution of Cats: Sabertooth vs. Regular:

There are two kinds of “true cats”. Cat experts call one type feline or “modern” partly because they are the ones that did not go extinct. If you have a pet cat, it’s a modern/feline cat. This also includes the lions, tigers, leopards, etc. The other kind are called “sabercats” because this group includes the saber tooth. It is generally believed but not at all certain that these two groups of cats are different phylogenetic lineages (but that is an oversimplification).

Male fish deceive watching rivals about their top choice of females:

They say that all’s fair in love and war, and that certainly seems to be the case of Atlantic mollies (Poecilia mexicana). These freshwater fish are small and unassuming, but in their quest to find the best mates, they rely on a Machiavellian misdirection.

CLOACA, the Defecation Device:

This made me wonder – what exactly IS poop? Other than having a vague idea of nutrients, bacteria, and fiber, I had never deeply contemplated it before.

Crayfish, warming up for a fight!

Do you remember this study (also see it here, here, here) we did a few years ago?
Well, I just got my hands on some pictures from the time we did it – just individual animals, not pairs as they fought (we had to pay attention to score behaviors, not waste time on taking pictures):
NCSU%20lab%20009.jpg

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PZ is all over the place today!

PZ just had a book review published in Nature:

Science and evolution have an advocate in Kenneth Miller, one of North America’s eminent knights-errant, a scientist who is active in defending evolutionary theory in the conflict between evolution and creationism. He has been at the centre of many recent debates about science education, most prominently testifying against intelligent design creationism in Pennsylvania’s Dover trial, which decided that intelligent design was a religious concept that should not be taught in public schools. He is also a popular speaker, offering the public a grass-roots defence of good science education. Miller’s new book Only a Theory is a tour of creationist misconceptions about evolution, such as the one referred to in the book’s subtitle — a creationist predicted an inevitable victory in the Dover trial because evolution is “only a theory”. The book is also a celebration of the power of evolutionary theory to explain our existence.

Also, as a part of a Forbes Magazine’s special report on commuting, PZ had an article published today – Do Animals Commute?

Whether an animal commutes or not is less a function of the work they must do than of whether they actually have something that might be called a home, a haven, a shelter. We don’t just invest ourselves full-time in the job–if we did, we might as well spare ourselves the commute and live in the office–but instead make the effort to set up a place of our own, a safe spot where we can relax, raise a family, or pursue activities that aren’t directly related to simply feeding ourselves.
And for that, we and other animals will make the sacrifice of sinking time and energy into shuttling between a place of profit and a place of refuge. If you want to know if a particular animal engages in anything like a commute, just ask if it has anything you would call a home.

Lively discussion of commuting, of course, follows in the comments. I wish more people were commenting on animals’ movements, but OK, people like to talk about themselves and other people-worries.

Why do earthworms come up to the surface after the rain?

ResearchBlogging.orgBelieve it or not, this appears to have something to do with their circadian rhythms!
Back in the 1960s and early 1970s, there was quite a lot of research published on the circadian rhythms in earthworms, mostly by Miriam Bennett. As far as I can tell, nobody’s followed up on that work since. I know, from a trusted source, that earthworms will not run in running-wheels, believe it or not! The wheels were modified to contain a groove down the middle (so that the worm can go only in one direction and not off the wheel), the groove was covered with filter paper (to prevent the worm from escaping the groove) and the paper was kept moist with some kind of automated sprinkler system. Still, the earthworms pretty much stood still and the experiments were abandoned.
Dr.Bennett measured locomotion rhythms in other ways, as well as rhythms of oxygen consumption, light-avoidance behavior, etc. With one of my students, some years ago, I tried to use earthworms as well – we placed groups of worms in different lighting conditions (they were inside some soil, but not deep enough for them to completely avoid light) – the data were messy and inconclusive, except that worms kept in constant light all laid egg-cases and all died (evolutionary trade-off between longevity and fecundity, or just a last-ditch effort at reproduction before imminent death?). Worms in (short-day and long-day) LD cycles and in constant dark did not lay eggs and more-or-less survived a few days.
I intended to write a long post reviewing the earthworm clock literature, but that was before I got a job….perhaps one day. But the news today is that there is a new paper that suggests that clocks may have something to do with a behavior all of us have seen before: earthworms coming out to the surface during or after a rain.
In the paper, Role of diurnal rhythm of oxygen consumption in emergence from soil at night after heavy rain by earthworms, Shu-Chun Chuang and Jiun Hong Chen from the Institute of Zoology at National Taiwan University, compared responses of two different species of earthworms, one of which sufraces during rain and the other does not. They say:

Two species of earthworms were used to unravel why some earthworm species crawl out of the soil at night after heavy rain. Specimens of Amynthas gracilis, which show this behavior, were found to have poor tolerance to water immersion and a diurnal rhythm of oxygen consumption, using more oxygen at night than during the day. The other species, Pontoscolex corethrurus, survived longer under water and was never observed to crawl out of the soil after heavy rain; its oxygen consumption was not only lower than that of A. gracilis but also lacked a diurnal rhythm. Accordingly, we suggest that earthworms have at least two types of physical strategies to deal with water immersion and attendant oxygen depletion of the soil. The first is represented by A. gracilis; they crawl out of the waterlogged soil, especially at night when their oxygen consumption increases. The other strategy, shown by P. corethrurus, allows the earthworms to survive at a lower concentration of oxygen due to lower consumption; these worms can therefore remain longer in oxygen-poor conditions, and never crawl out of the soil after heavy rain.

So, one species has low oxygen consumption AND no rhythm of it. It survives fine, for a long time, when the soil is saturated with water. The other species has greater oxygen consumption and is thus more sensitive to depletion of oxygen when the ground is saturated with water. Furthermore, they also exhibit a daily rhythm of oxygen consumption – they consume more oxygen during the night than during the day. Thus, if it rains during the day, they may or may not surface, but if it rains as night they have to resurface pretty quickly.
Aydin Orstan describes the work in more detail on his blog Snail’s Tales, and he gets the hat-tip for alerting me to this paper.
Chuang, S., Chen, J.H. (2008). Role of diurnal rhythm of oxygen consumption in emergence from soil at night after heavy rain by earthworms. Invertebrate Biology, 127(1), 80-86. DOI: 10.1111/j.1744-7410.2007.00117.x

The Open Sleep Journal and The Phylogeny of Sleep Database

One of the latest additions (just two days ago, I think) to the Directory of Open Access Journals is a journal that will be of interest to some of my readers – The Open Sleep Journal. The first volume has been published and contains several interesting articles. One that drew my attention is The Phylogeny of Sleep Database: A New Resource for Sleep Scientists (PDF download) by Patrick McNamara, Isabella Capellini, Erica Harris, Charles L. Nunn, Robert A. Barton and Brian Preston. It describes how they built a database that contains information about sleep patterns in 127 mammalian species. The Database itself can be found here and one can search it by species, by what was measured, by physiological or environmental conditions in which sleep was measured, etc. It has links to research on everything from platypus and echidna, through humans and kangaroos, to elephants, giraffes and sloths.
Since one of the stated projects that will come out of the database is a publication of a book on the Evolution of Sleep, I looked around to see if they are interested in anything else apart from mammals. Looking at the Projects page, I see they intend to add birds to the database later on. But that is not enough. Sleep did not suddenly appear full-blown in mammals and separately in birds. There is a long history of sleep research in reptiles, amphibians and fish, as well as – more recently – in insects like cockroaches, honeybees and Drosophila. In order to study the origin, evolution and adaptive function of sleep we have to look at its precursors among the invertebrates, not just focus on mammals and birds.

Do sponges have circadian clocks?

Blogging on Peer-Reviewed Research

Do sponges have circadian clocks?Much of the biological research is done in a handful of model organisms. Important studies in organisms that can help us better understand the evolutionary relationships on a large scale tend to be hidden far away from the limelight of press releases and big journals. Here’s one example (March 30, 2006):

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Friday Weird Sex Blogging – Corkscrewing

Friday Weird Sex Blogging - CorkscrewingYou really think I am going to put this above the fold? No way – you have to click (First posted on July 7, 2006):

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Oxytocin and Childbirth. Or not.

Blogging on Peer-Reviewed Research

From the Archives

Blogging on Peer-Reviewed Research

When teaching human or animal physiology, it is very easy to come up with examples of ubiqutous negative feedback loops. On the other hand, there are very few physiological processes that can serve as examples of positive feedback. These include opening of the ion channels during the action potential, the blood clotting cascade, emptying of the urinary bladder, copulation, breastfeeding and childbirth. The last two (and perhaps the last three!) involve the hormone oxytocin. The childbirth, at least in humans, is a canonical example and the standard story goes roughly like this:

When the baby is ready to go out (and there’s no stopping it at this point!), it releases a hormone that triggers the first contraction of the uterus. The contraction of the uterus pushes the baby out a little. That movement of the baby stretches the wall of the uterus. The wall of the uterus contains stretch receptors which send signals to the brain. In response to the signal, the brain (actually the posterior portion of the pituitary gland, which is an outgrowth of the brain) releases hormone oxytocin. Oxytocin gets into the bloodstream and reaches the uterus triggering the next contraction which, in turn, moves the baby which further stretches the wall of the uterus, which results in more release of oxytocin…and so on, until the baby is expelled, when everything returns to normal.

As usual, introductory textbook material lags by a few years (or decades) behind the current state of scientific understanding. And a brand new paper just added a new monkeywrench into the story. Oxytocin in the Circadian Timing of Birth by Jeffrey Roizen, Christina E. Luedke, Erik D. Herzog and Louis J. Muglia was published last Tuesday night and I have been poring over it since then. It is a very short paper, yet there is so much there to think about! Oh, and of course I was going to comment on a paper by Erik Herzog – you knew that was coming! Not just that he is my friend, but he also tends to ask all the questions I consider interesting in my field, including questions I wanted to answer myself while I was still in the lab (so I live vicariously though his papers and blog about every one of them).
Unfortunately, I have not found time yet to write a Clock Tutorial on the fascinating topic of embryonic development of the circadian system in mammals and the transfer of circadian time from mother to fetus – a link to it would have worked wonderfully here – so I’ll have to make shortcuts, but I hope that the gist of the paper will be clear anyway.

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Hot Peppers – Why Are They Hot?

TITLE(First posted on July 21, 2006) Some plants do not want to get eaten. They may grow in places difficult to approach, they may look unappetizing, or they may evolve vile smells. Some have a fuzzy, hairy or sticky surface, others evolve thorns. Animals need to eat those plants to survive and plants need not be eaten by animals to survive, so a co-evolutionary arms-race leads to ever more bizzare adaptations by plants to deter the animals and ever more ingenious adaptations by animals to get around the deterrents.
One of the most efficient ways for a plant to deter a herbivore is to divert one of its existing biochemical pathways to synthetise a novel chemical – something that will give the plant bad taste, induce vomiting or even pain or may be toxic enough to kill the animal.

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Circadian Rhythms, or Not, in Arctic Reindeer

Blogging on Peer-Reviewed Research

Circadian Rhythms, or Not, in Arctic ReindeerA January 20, 2006 post placing a cool physiological/behavioral study into an evolutionary context.

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How do bats in a cave know if it is dark outside yet? Guest post by Anne Marie Hodge.

As traveling is not conducive to vigorous blogging (apart from posting travelogue pictures), I have asked a couple of friends to write guest posts here. The first to step up to the plate is Anne Marie who put together her passion for bats and my passion for biological clocks and wrote this fascinating post:

Blogging on Peer-Reviewed Research

Casinos on the infamous Vegas “strip” spare no expenses when it comes to extravagant decorations and architecture. You can find everything from indoor gondola rides to full-sized pirate ships that are sunk in mock-battles multiple times each day. One thing that you might notice, however, is that these massive, opulent buildings almost always lack windows in the rooms where major gambling activity takes place. The massive interior rooms echo with the bells of slot machines and the soft buzz of cards being dealt at hundreds of tables all throughout the day and night, and after several hours inside one of these caverns of opulence it is easy to forget what time of day it is supposed to be. That, of course, is the point: if you aren’t able to keep track of the passing hours by subtle cues such as the angle of the sun, casino managers hope that it will keep you (and your money) around for longer periods of time.
Fortunately, whether you are a high-rolling VIP showing off your Rolex or a more budget-minded tourist playing the quarter slots with your trusty plastic Aquatech strapped to your wrist, chances are you have some way to tell time even when you are sequestered from typical environmental day length clues. Other mammals, however, don’t have the luxury of mechanical time instruments. If even a few hours inside a windowless casino is enough to distort our natural perception of time, how do other mammals manage to keep regular daily rhythms?
Obviously, most mammals do not hang out in windowless casinos, and thus are able maintain circadian rhythms using external cues such as day length and temperature. Bora recently gave an excellent primer on mammalian circadian clocks, definitely check out that post for detailed information on how these rhythms are regulated.
Light cycles are crucial for proper circadian clock calibration, but some animals live in large, isolated places that lack both sunlight and slot machines. The most notable cave mammals are bats, the winged wonders of the mammal world. The idea that all bats are caves-dwellers is actually a misconception. Many bat species roost in trees, buildings, or “bat houses” put out by helpful humans in areas where natural forest roots have been destroyed. Studies have shown that day length is the most common factor regulating bats’ daily activity cycles. Foraging strategies and diet specialization seem to have an impact on what time of night specific species emerge from their roosts. Insectivorous species often begin foraging a bit before true sunset, in spite of exposing themselves to increased predation risk, in order to take advantage of the peaks in insect activity at dusk (Jones and Rydell 1994). Fruit eating bats can afford to sleep in a little, because their “prey” isn’t likely to go anywhere between dusk and full darkness, so it’s not worth risking increased predation by diurnal or crepuscular predators. Thus, being able to detect the rising and setting of the sun is crucial for these bats to regulate their activity cycles.
While many common species of bats never even venture into caves, some species do indeed roost in large caves that are entirely devoid of light. Without being able to see when the sun rises and sets, how do these little guys maintain regular circadian rhythms?
bat.JPGThe most extensive studies of the circadian rhythms of cave bats have focused on Hipposideros speoris, Schneider’s roundleaf bat, which is native to India and Sri Lanka. Back in the 1980s, a group from Madurai Kamaraj University did some fascinating work to determine how these bats are able to tell when it is time to leave the cave for foraging each night (Marimuthu et al. 1981). Within the cave roost, bats are isolated from both light and temperature fluctuations, so the researchers sought another explanation for how they calibrate their circadian clocks. They did this by capturing some of the bats within a large colony of H. speoris, then putting them in holding cages inside the original cave, to observe their activity patterns in situ without ever letting them access a chamber of the cave that could give them external light or noise cues.
So, what did the Cave Cage experiment tell us? Surprisingly, it appears that social interactions are the key. The bats were observed to become mildly active within the cave well before the sun went down, and they spent some time grooming and flitting around within the roost chamber. Some of those bats ventured in between the roost chamber and into an outer portion of the cave, “sampling” the light. Once adequate darkness set in, all of the bats (not just the “samplers,” left the cave to forage. The caged bats also increased their activity in sync with the rest of the colony, even though they were unable to “sample” the outer chambers. The researchers concluded that the bats’ circadian rhythms were entrained by social cues. Bats could have been responding to the noise of the wingbeats of the first bats to leave the cage, or there could have been active vocal signaling. Pheromones could also come into play, if specific hormones are released by “samplers” as they prepare to leave for foraging, signaling the rest of the colony that it is time to leave.
One question that immediately crossed my mind was how the bats know when to start stirring around in the first place, It seems probable that the nightly emergence “sets” their clocks so that they’re properly entrained to wake up slightly before sunset, using hormones such as melatonin to control the length of their sleep cycle. These are largely tropical bats, so day length does not vary much throughout the year, allowing them to have a fairly constant interval of sleep in between returning from foraging in the morning and waking up in the evening.
The group also observed activity patterns of captive bats kept inside a cave after exterminating all of the other bats that roosted there (not the most conscientious field method, but not quite as terrible as it sounds: it was a small bachelor roost and only two bats were killed). They found that bats that were isolated from conspecifics displayed “free run” activity cycles that were significantly less than 24 hours long. Thus, it appears that the bats use social cues from other colony members to time their outflight.
There is no information on whether the same individuals are “samplers” each night, although that would be a fascinating study. While social cues do appear to play a large factor in determining the circadian rhythms of H.speoris colonies, sunlight is still a factor: the “samplers” couldn’t determine the time of day without sunlight available for sampling. The researchers did a follow-up study a few years later that shows that both light and conspecific communication are necessary to maintain accurate cycles. This time, they illuminated a cave around the clock (Marimuthu and Chandrashekaran 1983). Being exposed to constant light, with conspecifics resulted in free run cycles longer than 24 hours, as opposed to the shortened cycles displayed by isolated bats in constant darkness, showing that light cues facilitated by social communication appear to entrain the circadian clocks of these bats.
So, it appears that some bats depend upon social cues to help regulate their circadian clocks, with a few individuals in the colony serving as light “samplers” and alerting the other bats when it is time to emerge for nightly foraging. They still depend upon light cues for regulation, but the significant factor is that only a few actually see the light levels before emerging each evening, the rest rely upon social cues to tell them when it’s dinner time and entrain their internal clocks.
1. Image credit: Phil Richardson
References:
Jones, and Rydell. 1994. Foraging strategy and predation risk as factors influencing emergence time in echolocating bats. Phil. Trans. R. Soc. Lond. B. 345: 445-455.
Marimuthu, G.S. and M.K. Chandrashekaran. 1983. Continuous light inside a cave abolishes the social synchronization of the circadian rhythm in a bat. Behavioral Ecology and Sociobiology. 12: 321-323.
Marimuthu, G., S. Rajan, and M.K. Chandrashekaran. 1981. Social entrainment of the circadian rhythm in the flight activity o fthe microchiropteran bat Hipposideros speoris. Behavioral Ecology and Sociobiology, 8: 147-150.

Influence of Light Cycle on Dominance Status and Aggression in Crayfish

Influence of Light Cycle on Dominance Status and Aggression in CrayfishIn this post from April 06, 2006, I present some unpublished data that you may find interesting.

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Spiders and Bycicles

From The Archives
Since everyone is posting about spiders this week, I though I’d republish a sweet old post of mine, which ran on April 19, 2006 under the title “Happy Bicycle Day!” I hope you like this little post as much as I enjoyed writing it:

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Why is it called a ‘zebra crossing’?

Because that is where zebras cross the road (hat-tip)

Elephants successfully avoid landmines

Elephants avoiding mines:

Eliminated from Angola during more than two decades of civil war, herds of African elephants are crossing heavily mined fields as they recolonize Angola from neighboring Namibia and Botswana.
But miraculously, they are avoiding the mines entirely, according to researchers at University of Massachusetts in Amherst who are tracking them via global positioning system satellites.

Hat-tip.

Alan Alda at the N.C. Zoo

He was here last Tuesday for filming of a scientific documentary for PBS:

He was doing important work on an upcoming PBS special “The Human Spark”, a three-part documentary about what makes us human, due to air next year.
Alda, who also met with researchers at Duke University on Monday, started filming last week and said he will tape additional segments in France, England and South Africa, as well as in the Pacific Northwest. Duke primatologist Brian Hare suggested the NC Zoo as a shooting location, zoo spokesman Rod Hackney said.

Patricia Brennan on bird genitalia

News from SCONC:

On Thursday, March 27 at 4 p.m., the Zoology Department at NCSU will host a seminar from Patricia Brennan of Yale University entitled “The Biology of Avian Genitalia: Form and Function.” Brennan’s work on the genital anatomy of waterfowl has revealed the existence of a “sexual arms race” between males and females. Unlike 97 percent of bird species, male waterfowl have a phallus, and it can range “from a half-inch to more than 15 inches long.” The seminar will be held in 101 David Clark Labs. Refreshments will be served in the lobby at 3:45.

Related:
Friday Weird Sex Blogging – The Birds Do It….
More on duck phalluses and uteri

Don’t try this at home

See the moment when the lion recognizes the guys who raised him as a cub:

Hat-tip: Melissa

New Journal Club on PLoS ONE – Chimps exchange fruit for sex

A paper published back in September – Chimpanzees Share Forbidden Fruit by Hockings et al. is getting renewed attention these days.
Rebecca Walton has compiled links to the recent media and blog coverage of the paper (including those by my SciBlings Afarensis, Greg Laden and Brian Switek), the peer-reviewer’s comments have been added to the paper, and The Animal Cognition Research Group at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany has posted a series of comment as part of a Journal Club on this paper.
Now, all you need to do is join in the conversation – log in (or register if you have not done it already) and add your thoughts about chimps sharing forbidden fruit to the comments, ratings and annotations on this paper. If you decide to write a blog post, please send a trackback or, if that fails, leave us the link to your post in the comments on Rebecca’s blog post.

Animal Cognition

Thanks to John Wilkins, I want to point you to an excellent review on the current state of research (both scientific and philosophical) in Animal Cognition.

Clocks and Migratory Orientation in Monarch Butterflies

Blogging on Peer-Reviewed Research

I had no time to read this in detail and write a really decent overview here, perhaps I will do it later, but for now, here are the links and key excerpts from a pair of exciting new papers in PLoS Biology and PLoS ONE, which describe the patterns of expression of a second type of cryptochrome gene in Monarch butterflies.
This cryptochrome (Cry) is more similar to the vertebrate Cry than the insect Cry, also present in this butterfly. The temporal and spatial patterns of expression of the two types of Cry suggest that they may be involved in the transfer of time-information from the circadian clock to the brain center involved in spatial orientation during long-distance migration.
The PLoS Biology paper looks at these patterns of expression, while the PLoS ONE paper identifies a whole host of genes potentially implicated in migratory behavior, including the Cry2. Here is the PLoS Biology paper:
Cryptochromes Define a Novel Circadian Clock Mechanism in Monarch Butterflies That May Underlie Sun Compass Navigation:

During their spectacular fall migration, eastern North American monarch butterflies (Danaus plexippus) use a time-compensated sun compass to help them navigate to their overwintering sites in central Mexico. The circadian clock plays a critical role in monarch butterfly migration by providing the timing component to time-compensated sun compass orientation. Here we characterize a novel molecular clock mechanism in monarchs by focusing on the functions of two CRYPTOCHROME (CRY) proteins. In the monarch clock, CRY1, a Drosophila-like protein, functions as a blue-light photoreceptor for photic entrainment, whereas CRY2, a vertebrate-like protein, functions within the clockwork as the major transcriptional repressor of the self-sustaining feedback loop. An oscillating CRY2-positive neural pathway was also discovered in the monarch brain that may communicate circadian information directly from the circadian clock to the central complex, which is the likely site of the sun compass. The monarch clock may be the prototype of a clock mechanism shared by other invertebrates that express both CRY proteins, and its elucidation will help crack the code of sun compass orientation.

Here is the editorial synopsis:
In Monarchs, Cry2 Is King of the Clock:

Back in the brain, the authors showed that Cry2 was also found in a few dozen cells in brain regions previously linked to time-keeping in the butterfly, and this Cry2 underwent circadian oscillation in these cells, but not in many other cells that were not involved in time keeping. By taking samples periodically over many hours, they found that nuclear localization of Cry2 coincided with maximal transcriptional repression of the clockwork, in keeping with its central role of regulating the feedback cycle. This is a novel demonstration of nuclear translocation of a clock protein outside flies.
Finally, the authors investigated Cry2’s activity in the central complex, the brain structure that is believed to house the navigational compass of the monarch. Monarchs integrate information on the position of the sun and the direction of polarized light to find their way from all over North America to the Mexican highlands, where they spend the winter. Cry2, but not the other clock proteins, was detected in parts of the central complex where it undergoes strong circadian cycling. Some cells containing Cry2 linked up with the clock cells, while others projected toward the optic lobe and elsewhere in the brain.
Along with highlighting the central importance of Cry2 in the inner workings of the monarch’s clock, the results in this study suggest that part of the remarkable navigational ability of the butterfly relies on its ability to integrate temporal information from the clock with spatial information from its visual system. This allows the monarch to correct its course as light shifts across the sky over the course of the day. Other cues used for charting its path remain to be elucidated.

This is the PLoS ONE paper:
Chasing Migration Genes: A Brain Expressed Sequence Tag Resource for Summer and Migratory Monarch Butterflies (Danaus plexippus):

North American monarch butterflies (Danaus plexippus) undergo a spectacular fall migration. In contrast to summer butterflies, migrants are juvenile hormone (JH) deficient, which leads to reproductive diapause and increased longevity. Migrants also utilize time-compensated sun compass orientation to help them navigate to their overwintering grounds. Here, we describe a brain expressed sequence tag (EST) resource to identify genes involved in migratory behaviors. A brain EST library was constructed from summer and migrating butterflies. Of 9,484 unique sequences, 6068 had positive hits with the non-redundant protein database; the EST database likely represents ~52% of the gene-encoding potential of the monarch genome. The brain transcriptome was cataloged using Gene Ontology and compared to Drosophila. Monarch genes were well represented, including those implicated in behavior. Three genes involved in increased JH activity (allatotropin, juvenile hormone acid methyltransfersase, and takeout) were upregulated in summer butterflies, compared to migrants. The locomotion-relevant turtle gene was marginally upregulated in migrants, while the foraging and single-minded genes were not differentially regulated. Many of the genes important for the monarch circadian clock mechanism (involved in sun compass orientation) were in the EST resource, including the newly identified cryptochrome 2. The EST database also revealed a novel Na+/K+ ATPase allele predicted to be more resistant to the toxic effects of milkweed than that reported previously. Potential genetic markers were identified from 3,486 EST contigs and included 1599 double-hit single nucleotide polymorphisms (SNPs) and 98 microsatellite polymorphisms. These data provide a template of the brain transcriptome for the monarch butterfly. Our “snap-shot” analysis of the differential regulation of candidate genes between summer and migratory butterflies suggests that unbiased, comprehensive transcriptional profiling will inform the molecular basis of migration. The identified SNPs and microsatellite polymorphisms can be used as genetic markers to address questions of population and subspecies structure.

Here is an article written after the press release, which, as such articles usually do, greatly overstates the extent of the findings:
Clocking monarch migration:

In previous work, Reppert and his team showed that pigment-producing genes in the monarch eye communicate with the butterfly’s circadian clock. As part of the new study, Reppert and his team also found, in an area of the monarch brain called the central complex, a definitive molecular and cellular link between the circadian clock and the monarch’s ability to navigate using the sun. Briscoe said that Reppert’s study was “really going to overturn a lot of views we had about the specific components of circadian clocks.”

The spatial and temporal patterns of expression make Cry2 the most serious candidate for the connection between the clock and the Sun-compass orientation mechanism. Much work, both at the molecular and at higher levels of organization needs to be done to figure out the exact mechanism by which this animal, during migration, compensates for the Sun’s movement across the sky during the day, and thus does not stray off course. Cry2 appears to be a good molecular “handle” for such studies.
For background, see my older post on the initial discovery of Cry2 in Monarch butterflies by the same team.

Pilobolus, Antlion and the Vertebrate Eyes

On Pilobolous:
When I first wrote my post on Pilobolus (here and here) I really wanted to do something extra, which I could not do at the time. If you scroll down that post, you will see I reprinted the Figure 1 from the Uebelmesser paper. What I wanted to do was find (and I asked around for something like that) the exact times of dawn and dusk at the site where Uebelmesser did her work and thus be able to figure out the dates when the tests were done and the exact phase-relationship between the dawn and the time when Pilobolus shoots its spores.
Now, I see that such a chart exists (via) and I can, if I find time and energy, do it one of these days. Then, I can do the same thing for the Chapel Hill coordinates, go out to a nearby farm, and repeat the experiment myself.
On Antlions:
I knew, when I wrote my post on antlions (here and here) that they had endogenous circalunar rhythms. But today, I also learned that:
– antlions secrete a toxin that paralyses their prey
– the antlion toxin is produced by its bacterial endosymbiont Enterobacter aerogenes
– the normal function of that toxin in the bacterial cell is as a chaperonin, i.e., a protein that makes sure that other proteins are folded correctly into their normal 3D shapes
– the Enterobacter aerogenes toxin is very similar to a protein made by Escherichia coli
– the Enterobacter aerogenes toxin is 1000 times more toxic to cockroaches than the E.coli one
– neither of the proteins is toxic to mice (and presumably to us).
One learns something new and cool every day.
On Vertebrate Eyes:
Eye is a very important organ in my own specialty, so I was surprised to see how much new I learned by reading this eye-opening post by PZ. Bookmarked for future use in teaching….

Now We Are Six*

Blogging on Peer-Reviewed Research

Is there any kid who does not love giraffes? They are just so amazing: tall, leggy, fast and graceful, with prehensile tongues and a need to go through complex calistehnics in order to drink. The favourites at zoos, in natural history museums and on TV nature shows.
Giraffes were also important players in the history of evolutionary thought and I bet you have all seen, and heard the criticisms of, the iconic comparison between Lamarck’s and Darwin’s notions of evolution using a comic strip featuring giraffes and how they got their long necks.
Giraffes sleep very little and mostly standing on their feet. They give birth while standing, with no apparent ill consequences to the newborn which, after falling from such a great height, gets up on its feet and is ready to walk and run with the herd within minutes.
Like almost any other mammalian species, a giraffe can sometimes be born albino, but in this case only the yellow background is white, while the brown splotches remain (similar to the “tuxedo” mutation in quail) suggesting that just one of the multiple “color” genes is malfunctioning.
The behavioral (sexual selection) hypothesis that the length of the giraffes’ necks has something to do with male-male fighting, co-called “necking”, is apparently going out of favor, while more ecological hypotheses are gaining in acceptance (again – this appears to be cyclical).
But, one thing that you think when you think of giraffes is the giraffe, i.e., one thing, one species. There have been inklings recently that this thinking may change, finally culminating in a very interesting paper published yesterday in Journal of Biology (free pdf of the paper is available):

A central question in the evolutionary diversification of large, widespread, mobile mammals is how substantial differentiation can arise, particularly in the absence of topographic or habitat barriers to dispersal. All extant giraffes (Giraffa camelopardalis) are currently considered to represent a single species classified into multiple subspecies. However, geographic variation in traits such as pelage pattern is clearly evident across the range in sub-Saharan Africa and abrupt transition zones
between different pelage types are typically not associated with extrinsic barriers to gene flow, suggesting reproductive isolation.
By analyzing mitochondrial DNA sequences and nuclear microsatellite loci, we show that there are at least six genealogically distinct lineages of giraffe in Africa, with little evidence of interbreeding between them. Some of these lineages appear to be maintained in the absence of contemporary barriers to gene flow, possibly by differences in reproductive timing or pelage-based assortative mating, suggesting that populations usually recognized as subspecies have a long history of reproductive isolation. Further, five of the six putative lineages also contain genetically discrete populations, yielding at least 11 genetically distinct populations.
Such extreme genetic subdivision within a large vertebrate with high dispersal capabilities is unprecedented and exceeds that of any other large African mammal. Our results have significant implications for giraffe conservation, and imply separate in situ and ex situ management, not only of pelage morphs, but also of local populations.

In other words, there appear to be more than one species of giraffes currently living in Africa – probably six species, and perhaps as many as eleven. And while the individuals of different giraffe species readily mate in captivity, it seems not to happen out in the wild.
Furthermore, two of those six new species belong to very small and shrinking populations. If the finding of this paper is accepted by the scientific community and the six populations receive official recognition as six species, this will turn the two smallest populations into endangered species, worthy of our protection.
An anonymous commenter on Grrrl’s blog has a great idea and I think we should start a contest: make a picture of Noah’s Ark with SIX pairs of giraffes towering over all the other pairs of animals instead of just one pair. Feel free to make it a LOLgiraffe picture. Post the links in the comments here or on Grrrl’s post and we’ll highlight them and pronounce the winners after the holidays.
* Apologies to A.A.Milne

Heh! Wait till you see her play bagpipes!

Have you hugged your horse today?

The other day, Kate wrote an interesting post about inter-species relationships, in particular the cases of inter-species adoption and parenting. In her post, she mentioned a paper that immediately drew my attention – Influence of various early human-foal interferences on subsequent human-foal relationship. by Henry S, Richard-Yris MA and Hausberger M. (Dev Psychobiol. 2006 Dec;48(8):712-8.).
In the paper, the newborn foals were either handled by humans (e.g., brought to the teat), or left completely alone with their mother, or just had humans standing by. Then, a few weeks later, they tested the foals as to their response to human handling. Those that were handled immediately after birth responded less positively than the controls and those that had just a presence of humans had a better response than the controls (in a nutshell – the study is more complicated than that, but this will suffice for now).
As someone who has spent my life around horses, I grokked this intuitively. The idea of “imprinting”, as I understood it at the time it was popular a couple of decades ago, did not mean, in my mind, force-handling newborn foals. It just meant ‘being there’. Letting the mare and foal do their stuff for the first few hours. Then, instead of letting the mares and foals out in the pasture for two years before trying to handle the semi-wild youngsters, making sure that the foals get used to the daily presence of humans, and gradually more and more interaction with humans, including touching and handling.
The paper is described as a test of “imprinting” but I am not sure – has anyone actually tried to imprint by force-handling foals at birth? Was that what imprinting ended up meaning? Or is the paper misinterpreting the idea?
I have raised a foal. My good friend and colleague, a veterinarian, was there when my horse was born. He let the nature take its course. For the first month, the dam was handled daily and they both spent time outside in the presence of humans, but nobody touched the foal. When I got him at six months of age, I spent the first night sitting in his food-trough, talking softly. He calmed down after a couple of hours, finally fell asleep, and later came over to me, sniffed me and nuzzled me. It never occurred to me to pat him as I never expected that to be a naturally soothing experience – “Yeesh, yuck, he…touched me!”.
But I spent hours every day with him afterwards. By the time he turned 1, I could catch him in the paddock (OK, the trick was to offer some tangerines), groom him, pick up his legs and trim his hooves, put a blanket on him, trim his whiskers with an electrical trimmer, lead him on the halter, lunge him, long-rein him, load him on the single-horse trailer and drive him around. At the age of 2, I had no problem putting the saddle on and getting on top myself. For the rest of his life he was a perfect gentleman in and out of the barn, easily handled by kids. He was not as easy to ride later on, I hear, which is surprising as I had no trouble riding him the first few months of his riding career. Last time I went home, back in 1995, I watched him do great at the Young Horse division of the showjumping championship of Serbia. I heard he started refusing to jump later and broke someone’s arm in the process. He subsequently won the dressage championship of Serbia with another rider. You can see a picture of him from his later years here.
I always thought that people patted horses because it feels good to the human, not the horse. The proper reward for work well done is rest – letting the reins long, walking the horse, taking him away from the noise of the show-ring to a quiet corner, giving him a bath, a stall full of fresh straw and some nice food, e.g., a warm bran-mash with apples and carrots (and garlic cloves – they LOVE it and their hair gets so shiny). The pat on the neck that a horse gets after running a good race or jumping a nice course is not in itself a reward. It is just a learned signal that the work is over and that the horse can now relax.

Antelopes Gone Wild!

Kate describes an unusual reproductive system in topi antelopes in which the fertile females are extremely promiscuous (but choosy) and aggressive. Not what you learned in school under the “mate choice” and “male-male competition” topics in your Animal Behavior classes….

Tinamou’s Dilemma: Canines or Talons?

When I first read about a new paper about the behavior and ecology of maned wolves, I immediately thought of the blogger most uniquely qualified to write about it. Anne-Marie’s research is on maned wolves and in her latest post she describes an ecological love-hate triangle in which the maned wolves flush out birds, mostly tinamous, out of the bushes – just to have them preyed upon by hawks. Anne-Marie provides more details, the back-story and the cute pictures.

Don’t go near that empty beer bottle if your metabolism is fast!

That is, if you are a shrew and do not want to be just a dead data-point for some ingenious young ecologists….who at least clean up the tricky trash left by drunk drivers.

New on….

…the computers and the Web:
If you are not clear about the difference between the Net (aka Internet), the Web (aka World Wide Web) and the Graph (aka Social Graph), then this post is a must read (via Ed). He explains much more clearly what I had in mind before, e.g., here.
In order to use the Net, the Web and the Graph, you do need some kind of a machine, perhaps a computer, and Greg Laden puts together a dream (or nighthmare) setup for you!
Speaking of dream computers, I could not resist… as you may have seen before, Professor Steve Steve and I got to play with the XO laptop back at Scifoo and, after he nagged me and nagged me and nagged me, I finally succumbed and bought one (which means that another one will go to a poor child somewhere in the developing world – something you should consider doing yourself, but have to think fast as there are only four days left! Update: just saw that it was extended to December 31st…). I am sure that OLPC is inundated with orders and it will take weeks for the laptop to arrive, but once it does, my wife, both of my kids and myself (and Prof. Steve Steve, of course) will give it a test run and I will let you know what we collectively think about it.
Steve%20Steve%20and%20the%20%24100%20laptop%202.jpg
Speaking of laptops for kids, why not ask the kids how they would like to see them designed? That is what Amy did (she sometimes comes to my office to get coffee) and you can see the results here (hat-tip: Anton). Pets, Harry Potter trivia, weird games and really weird games….
…North Carolina animals:
Carnivore Preservation Trust has a great website, but most importantly, they now have a brand new IT system that connects it to researchers and veterinarians around the world. The Trust is just minutes away from where I live, but until recently, one could not just show up and go inside (they have tours now, but you have to call in advance, etc.). So, either you knew someone there who can let you in, or you volunteer for a day (or regularly) fixing cages, feeding the animals, etc. I have not been yet, but I will find some time to go soon.
The special exhibit, Dinosaurs: Ancient Fossils, New Discoveries is now open at the North Carolina Museum of Natural Sciences in Raleigh.
The students at the Asheboro Zoo School are spending three days a week cleaning and taking care of 150 Puerto Rican crested toads that were supposed to be euthanized, but due to the effort by veterinarians and students will probably make it.
This is how animals at the NC Zoo are fed:

Where does a fruitfly go when it goes out for a walk?

Last week’s PLoS ONE paper, Analysis of the Trajectory of Drosophila melanogaster in a Circular Open Field Arena, is the subject of the newest Journal Club. It is an interesting methods paper, showing the way a camera and some math can be used for a much more sophisticated analysis of animal behavior than it has traditionally been done.
The Journal Club this week is being led by Bjoern Brembs from the Institute of Biology – Neurobiology, Freie Universitat Berlin. You may be familiar with his name because Bjoern also writes a science blog.
The group has now posted some initial commentary, in particular a list of questions. It is now up to YOU to go and add your voice to the Journal Club – answer the questions if you can, or ask new questions, or just post a brief comment.
Here is the abstract, and you go read the entire paper, rate, comment, annotate, blog about and send trackbacks:

Background
Obtaining a complete phenotypic characterization of a freely moving organism is a difficult task, yet such a description is desired in many neuroethological studies. Many metrics currently used in the literature to describe locomotor and exploratory behavior are typically based on average quantities or subjectively chosen spatial and temporal thresholds. All of these measures are relatively coarse-grained in the time domain. It is advantageous, however, to employ metrics based on the entire trajectory that an organism takes while exploring its environment.
Methodology/Principal Findings
To characterize the locomotor behavior of Drosophila melanogaster, we used a video tracking system to record the trajectory of a single fly walking in a circular open field arena. The fly was tracked for two hours. Here, we present techniques with which to analyze the motion of the fly in this paradigm, and we discuss the methods of calculation. The measures we introduce are based on spatial and temporal probability distributions and utilize the entire time-series trajectory of the fly, thus emphasizing the dynamic nature of locomotor behavior. Marginal and joint probability distributions of speed, position, segment duration, path curvature, and reorientation angle are examined and related to the observed behavior.
Conclusions/Significance
The measures discussed in this paper provide a detailed profile of the behavior of a single fly and highlight the interaction of the fly with the environment. Such measures may serve as useful tools in any behavioral study in which the movement of a fly is an important variable and can be incorporated easily into many setups, facilitating high-throughput phenotypic characterization.

Are you a naked mole-rattist?

Do you agree that Naked Mole Rats are beautiful? Does it irk you to no end when you hear someone state that they are ugly? Does it make you mad when the MSM, oblivious, ignorant and insensitive, repeats that standard denialists’ trope? Are you sick-and-tired of the “he-said-she-said” journalism that just HAS to, every time, quote some anti-naked-mole-rat bigot whenever these lovely animals are mentioned? Are you aware that a Heterocephalus glaber is not allowed to run for office in 27 states of the USA? These days, you cannot even slander atheists in a political speech any more without paying the price at the polls, yet it is deemed perfectly normal to crack jokes at the poor defenseless rodent! Why? Just because it is hairless, i.e., DIFFERENT than most of us!
No, my friends! It is time to stand up to these naked mole-rattists! Join the Facebook group and report all the ugly slurs to the rest of the group members, so we can incur the wrath of the Internets on those who still harbor the “old time” resentments toward this beautiful cousin of ours.
And just because they are blind does not mean they do not have eyes or cannot detect light. While the image-processing structures are greatly diminished, their circadian photoreception is intact. And, when monitored one-by-one (i.e., not in a colony setting the way Paul Sherman initially and erronoeusly reported), some individuals display circadian rhythms in activity and body temperature. The strongest, clearest rhythms are exhibited by the disperser morphs – those males who leave the colony and travel some ways trying to find and join another colony elsewhere.

Running, breathing and being a horse

Yesterday, Chris Clarke wrote a post that I read three times so far, then finally submitted it myself for Reed’s consideration for the anthology. Most science bloggers are excellent writers, but rare is the gift that Chris displays in many a post, of weaving many threads into a coherent story that is also gripping and exciting – even when he writes about stuff like respiratory physiology, something that usually puts students to sleep in the classroom. But add a dash of evolution, a cool movie, some dinosaurs, and a personal experience and suddenly the story comes alive for the reader.
This was started as a comment on his blog, but it got long so I decided to put it here instead. You need to read his post in order to understand what in Earth I am talking about.
Human, like a horse.
First, I used to run a lot when I was in middle/high school. My favourite distances were 800m and 1500m and I usually held the school record and came in the top 10 in my age group for the city of Belgrade (pop. 2 mil.). Sure, I am lightweight and have ling legs, but I attributed my success to breathing – in exactly the same way Chris describes: 4 steps to inhale, 4 steps to exhale to begin with, then reducing it to 3, 2 or even 1 step for each inhalation and exhalation as I am approaching the finish line (or on an uphill). I was also breathing very loudly – sounding almost like a horse. And I actually imagined being a horse when I ran – a little imagery helps squeeze those last ounces of energy out of painful muscles in the end.
Horse, like a human.
Back in 1989 or so, I rode a champion sprinter racehorse throughout his winter fitness program, which was pretty much miles and miles of trotting around the track as a part of interval training. He was already getting older at the time and skipped two entire racing seasons out in the pasture, so he needed a good fitness program in order to get back on track and face the younger horses. Two decades later, he still holds the national and track records on 1000m and 1300m, going a kilometer well inside a minute. Translation: a damned fast horse! When the spring came and the professional jockeys arrived, it was time for me to give the horse to them to continue with the fast portion of the training. But, the owners wanted to reward my work by letting me, just once, get the feel for the speed. So, I took him out on the track and started in a steady canter around the course. The old campaigner knew just what to do – when we passed the last curve and entered the final stretch he took in one HUGE breath that made his chest almost double in diameter (I almost lost my stirrups at that moment when he suddenly widened) and took off. There was no way I could look forward without goggles – too much wind in my face. That was friggin’ fast! About 60km/h, I reckon, for that short burst of energy. And, during that entire final stretch he did not breath at all – he did it pretty much all on that one large breath plus anaerobic respiration. Chris, in his post, explains why horses do that. Oh, and that summer, the horse devastated his younger buddies by winning the biggest sprint of the year by several lengths, leaving the rest of the field, including that year’s Derby winner, in a cloud of dust. The audience roared as he was always a people’s favourite.
Horse and human, like a centaur.
One of the most important things in riding horses, something I always did and always taught, although it is rarely taught by others or mentioned in books, is the necessity for the rider to breath in sync with the horse’s movement. This is especially important when riding a nervous or spirited young horse who would otherwise explode. When trotting – three steps for inhale, three for exhale. Canter is more complicated. Stopping breathing leads to stiffening of the body which the horse immediately detects and it makes the horse nervous and more liable to stop at a jump or do something dangerous. It is easy to teach the adults to breath. But for the little kids, they forget, or even do not understand exactly what I am asking them to do. So, I made them sing while jumping courses. If you sing you have to breath all the time. You cannot stop breathing. So, Twinkle Twinkle Little Star got many a scared little kid over all the jumps in my classes as breathing relaxed them and gave their ponies confidence to jump.