Category Archives: Animal Behavior

At The Zoo

Thanks to a bout of warm weather, the new triplet lion cubs at the NC Zoo in Asheboro have been placed in the exhibit yesterday.
Until recently, the visitors could watch them on TV. You can see some pictures here and here and watch some videos here.

Mammoth Behavior and Bear Taxonomy

Did mammoths scratch themselves against rocks?

Parkman believes, and he has a growing body of evidence to prove that mammoths and other large Ice Age creatures once used these very rocks near Duncan’s Landing, along the Sonoma Coast State Beach, to scratch their backs. He claims the giant mammals rubbed so much that large swaths of rock have been buffered smooth.

Bears scratch against the trees, but which species is which? Lumpers vs. Splitters.

Alex and the Greys

Shelley scored quite a blogospheric scoop today – an exclusive interview with Irene Pepperberg.

Today on PLoS – Biology

Interspecific Communicative and Coordinated Hunting between Groupers and Giant Moray Eels in the Red Sea:

The article offers a description and accompanying videos, such as the one showing a grouper and eel swimming side by side as if they are good friends on a stroll. It also offers quantification, which is truly hard to achieve in the field, of the tendencies involved in this mutually beneficial arrangement. The investigators were able to demonstrate that the two predators seek each other’s company, spending more time together than expected by chance. They also found that groupers actively recruit moray eels through a curious head shake made close to the moray eel’s head to which the eel responds by leaving its crevice and joining the grouper. Groupers showed such recruitment more often when hungry.
Given that cooperative hunting increases capture success for each of the two predators, and that they don’t share with each other but swallow the prey whole, their behavior seems a form of “by-product mutualism,” defined as a form of cooperation in which both parties achieve rewards without sacrificing anything for the other. They are both out for their own gain, which they attain more easily together than alone.

Divergent Selection on Opsins Drives Incipient Speciation in Lake Victoria Cichlids:

Though Lake Victoria cichlids appear millions of years younger than their counterparts in nearby Lake Malawi, both groups display an enormous range of physical and behavioral traits. This staggering diversity in such young species provides compelling evidence for adaptive radiation, which occurs when divergent selection operates on ecological traits that favor different gene variants, or alleles, in different environments. When divergent selection on an ecological trait also affects mate choice–promoting reproductive isolation of diverging populations–ecological diversity and speciation may proceed in tandem and quickly generate numerous new species.
Despite substantial theoretical and some experimental support for such “by-product speciation,” few studies have shown that selection has “fixed” alleles (that is, driven its frequency in a population to 100%) with different effects on an adaptive trait in closely related populations. But now, Yohey Terai, Norihiro Okada, and their colleagues have bridged that gap by demonstrating divergent selection on a visual system gene that influences both ecological adaptation and mate choice in cichlids.

On the Orca that attacked its trainer

Dave explains the incident and gives some excellent background information way beyond what the media reported.

More on the elephant intelligence

It is not just mirrors that elephants can figure out – they can also flush toilets! [OK, jokes aside, click on the link to see what is really happening]

Elephants pass the mirror test

Humans do it, great apes do it, dolphins do it, now elephants (also here) have also been shown to do it – recognize themselves in the mirror, i.e., realize that the image in the mirror is the image of themselves and not a strange animal. That’s a biggie in the world of cognitive science and the study of evolution of consciousness:

When the mirror was unveiled in their yard, they immediately walked over and began poking and prodding and inspecting and playing. They used their trunks to inspect it and then themselves. Two got on their hind legs to look on top of the mirror. One got on the ground to inspect the bottom of it. They opened their mouths, exploring an area of their body they were familiar with but had never seen. They even brought their food over to eat in front of the mirror.
“All three of the elephants demonstrated this self-directed behavior,” said Joshua Plotnik, a co-author of the study and a graduate student at Emory. And like children inspecting their own bodies, the elephants put their eyes right up to the mirror, seemingly to figure out what it was and how it worked, he said. Then they investigated parts of their bodies they had never seen. They grabbed one of their ears and pulled it towards the mirror for inspection. “These are behaviors that they don’t normally do,” he added.
The scientists used a non-toxic paint to mark a small spot on one side of each animal’s forehead, which would be visible when it looked in the mirror. They also marked an identical spot on the other side of the forehead, but invisible paint was used to test whether the animals were seeing rather than feeling the mark.
Happy was the only one of the three who noticed the spot and used her trunk to examine it — over and over again. She did not go after the invisible spot on the other side of her forehead.

Magnetotactic Bacteria

Magnetoreception is one of the most fascinating sensory modalities in living organisms. Most of the work has been done in homing pigeons, migrating birds and salmon. More recently, work has been done in mammals and fruitflies. But this sense is not limited only to the most complex organisms – it is found in a number of bacterial species:
Researchers Reveal Mystery Of Bacterial Magnetism:

Scientists at the Naval Research Laboratory (NRL) and Purdue University have shed light on one of microbiology’s most fascinating mysteries–why some bacteria are naturally magnetic. Their description of how being magnetic “helps” the bacteria is reported in the August 2006 issue of the Biophysical Journal.

magnetobacterium.jpg
Magnetotactic bacteria were discovered by Blakemore in 1975. You can see some cool photomicrographs of different species of magnetotactic bacteria here.
The idea is that these bacteria, all of which prefer environments low in oxygen, use the Earth’s magnetic field in order to orient and swim down. Down is where the debris is decaying at the bottom of the lake and the oxygen concentration is likely to be much lower than up, at the surface of the lake.
Interestingly, bacteria caught in the Southern hemisphere have the polarity of the string of magnetite crystals directed in the opposite direction from the Northern hemisphere bacteria. Having a Northern arrangement in a Southern lake would produce the opposite effect – swimming up.
magnetic%20mutants.jpg
Some recent research on mutants (bacteria that do not produce magnetite or produce it but do not arrange them in strings), including this paper, suggest that magnetic sense (magnetotaxis) works together with teh chemical sense (aerotaxis) which tells the bacterium about the changes in oxygen concentrations so it can swim down the oxygen gradient (from high 02 towards the low 02 concentration):

NRL researcher Dr. Paul Sheehan adds, “by mathematically modeling their motion, we determined that being magnetic actually makes the bacteria much more sensitive to oxygen when in a magnetic field, so that they swim away from oxygen at much lower concentrations.” It is as if the climber gets tired and turns around sooner when heading up the mountain, keeping her from heading too far in the wrong direction. And the stronger the magnetic field, the bigger the effect. The scientists do not yet know how the magnetic field has this affect on the bacteria, and are currently conducting additional experiments to help answer that question.

Update: Brad wonders if this could have been the very first sensory modality. I doubt it. The assembly of the magnetite chain is quite a complex process. Some simple form of chemoreception probably came first – swimming towards or away from food and/or toxins in the water.

Clark’s Nutcracker

You may remember that Clark’s Nutcracker is one of my favourite birds, so I’ll be watching this guy (I am assuming he got his PhD with Nikki Clayton):
Researcher Uncovering Mysteries Of Memory By Studying Clever Bird:

Scientists at the University of New Hampshire hope to learn more about memory and its evolution by studying the Clark’s nutcracker, a bird with a particularly challenging task: remembering where it buried its supply of food for winter in a 15-mile area. Like many animals preparing for the winter, every fall the Clark’s nutcracker spends several weeks gathering food stores. What makes it unique is that it harvests more than 30,000 pine nuts, buries them in up to 5,000 caches, and then relies almost solely on its memory of where those caches are located to survive through winter.

Evolution Project And A Truly Fair And Balanced Fox

Evolution Project And A Truly Fair And Balanced FoxMeandering Musings on evolutionary psychology and many other things (from February 15, 2005)…

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New study on evolution of vision

For easy-to-understand quick look at the evolution of vision I have to refer you to these two posts by PZ Myers, this post of mine, and these two posts by Carl Zimmer.
Now, armed with all that knowledge, you will curely appreciate the importance of this new study:
Compound Eyes, Evolutionary Ties:

Biologists at the University of California, San Diego have discovered that the presence of a key protein in the compound eyes of the fruit fly (which glow at center due to a fluorescent protein) allows the formation of distinct light gathering units in each of its 800 unit eyes, an evolutionary change to an “open system” that enabled insects to make significant improvements in visual acuity and angular sensitivity. In contrast, beetles (shown surrounding the fruit fly), bees and many mosquito species have the light-gathering units fused together into a “closed system.”
In a paper published in this week’s early online edition of the journal Nature, the scientists report that one of three proteins needed to form these light gathering units is present in the visual system of fruit flies, house flies and other insects with open eye systems, but conspicuously absent in beetles, bees and other species with closed systems. The researchers showed that the loss of this protein, called “spacemaker,” can convert the eyes of fruitflies–which normally have open eye systems–into a closed one. In contrast, the introduction of spacemaker into eyes with a closed system transformed them into an open one.
Charles Darwin was so enamored by the intricate complexity of the eye that he wondered how it could have evolved. “These results help illustrate the beauty and power of evolution and show how ‘little steps’–like the presence of a single structural protein–can so spectacularly account for major changes in form and function,” said Charles Zuker, a professor of biology and neurosciences at UCSD and a Howard Hughes Medical Institute investigator, who headed the research team.

You’re ugly, but I like your kids anyway

Mother Birds Give A Nutritional Leg Up To Chicks With Unattractive Fathers:

Mother birds deposit variable amounts of antioxidants into egg yolks, and it has long been theorized that females invest more in offspring sired by better quality males. However, a study from the November/December 2006 issue of Physiological and Biochemical Zoology shows that even ugly birds get their day. Providing new insight into the strategic basis behind resource allocation in eggs, the researchers found that female house finches deposit significantly more antioxidants, which protect the embryo during the developmental process, into eggs sired by less attractive fathers.

It’s moved from sex steroids to antioxidants, I see. Can someone please send me this paper so I can comment more fully?

Lions’ manes

I saw this ScienceDaily report earlier today and thought: “What’s new?” I recall a study with similar conclusions from just a couple of months ago, and even that was not that new – I used the example in teaching about 5-6 years ago (then dropped the example as the literature got more and more contentious).
But a few minutes ago, Afarensis posted about this and cleared it up for me – the previous study was from zoos and this one is from the wild. Also, the new study incorporates ontogenetic data – the effects of age.
So, the size and color of the lion’s mane is not driven by sexual selection, but by thermoregulatory needs and it seems it takes some of the lions quite a lot of time to grow a big mane:

According to the overall findings of the study, wild lions generally develop manes in accordance with local climate regimes. In Equatorial east Africa, climate is determined by elevation. Thus lions with the most profuse manes occur at the upper limit of their altitudinal range, while similar aged males in the lowest and warmest environments like Tsavo typically carry only modest or scanty manes.
However, the authors also found, paradoxically, that the majority of lions in regions like the greater Tsavo ecosystem (which is famed for its “maneless” lions), did appear to acquire respectable manes, eventually, contrary to most recent popular and scientific accounts of the lions from that region.
“We knew about the climate/elevation correlation since we were the first to publish those preliminary results in GEO 2001, but this new development really threw us for a loop,” says Tom Gnoske, of the Field Museum’s Zoology Department and senior author of the paper. “However once we analyzed all of the statistical data we found a very strong correlation linking increased age and continued mane development, a significant variable ignored by all previous authors.”
Statistical data from this study demonstrates that the onset of mane development in lions living below an altitude of 800 meters on or near the equator is delayed, and that the “rate” or speed at which a mane develops in lions from those regions is slower on average than that of the more familiar lions living in the cooler, higher altitudes of the greater Serengeti ecosystem and elevated plains extending northward, such as the Athi/Kapiti Plains and beyond. According to the researchers, in environments like Tsavo that have especially high minimum temperatures throughout the year, lions in their reproductive prime–from the approximate ages of five thru seven years old–usually possess only very marginally developed manes, while most of the more thoroughly maned lions in those same territories were already well past their breeding prime.
Furthermore, the researchers found compelling evidence indicating that manes of lions from all populations continue to develop long after a lion has achieved sexual maturity, such that the best-maned lions in any region are typically of an older age class. “Usually lions are well past their breeding prime when they carry the most extensive and often darkest manes of their lives,” explains Kerbis Peterhans Adjunct curator of Mammals at The Field Museum, Professor at Roosevelt University, and co-author of the study.

Read the rest

My picks from ScienceDaily

Parasitic Wasps Protect Offspring By Avoiding The Smelly Feet Of Ladybirds:

Scientists at Rothamsted Research have identified how aphid parasitic wasps prevent their offspring being eaten by ladybirds. The tiny wasps implant their offspring parasitically into aphid pests, but should the aphid get eaten by a ladybird, the growing wasp would be consumed as well. The researchers, supported by the Biotechnology and Biological Sciences Research Council (BBSRC), have found that to protect their offspring, adult wasps have evolved to avoid the smell of a short-lived blend of chemicals that ladybirds deposit with each footprint they make. The scientists have identified the particular cocktail of chemicals.

Mosquitoes’ Sweet Tooth Could Be Answer To Eliminating Malaria:

Mosquitoes’ thirst for sugar could prove to be the answer for eliminating malaria and other mosquito-transmitted diseases, says Hebrew University researcher Prof. Yosef Schlein in a study published in the American Science magazine and the International Journal for Parasitology.

Crickets On Hawaiian Island Develop Silent Wings In Response To Parasitic Attack:

In only a few generations, the male cricket on Kauai, one of the Hawaiian Islands, underwent a mutation — a sudden heritable change in its genetic material — that rendered it incapable of using song, its sexual signal, to attract female crickets, according to a new study by UC Riverside evolutionary biologists.

That Fruitfly Will Beat You Up

Fruit Fly Aggression Studies Have Relevance To Humans, Animals:

Researchers in the North Carolina Sate University genetics department have identified a suite of genes that affect aggression in the fruit fly Drosophila melanogaster, pointing to new mechanisms that could contribute to abnormal aggression in humans and other animals.
The study, led by doctoral student Alexis Edwards in the laboratory of Dr. Trudy Mackay, William Neal Reynolds Professor of Genetics, appears online in PloS Genetics.
Feisty flies themselves may not be very scary, but their genes and biochemistry have more in common with those of humans than the casual observer might suspect, and geneticists can subject flies to experiments that simply can’t be done on higher organisms.
To measure aggression, the researchers starved male flies for an hour and a half, then gave them a small food droplet and watched them duke it out, counting the number of times a focal fly would chase, kick, box, or flick his wings at other flies.
“Some animals will very vigorously defend their little food patch, whereas others are relatively polite,” Mackay said. “To determine if this had a genetic basis, we conducted a selection experiment.”
For the selection experiment, Edwards pulled three groups of flies – high aggression, low aggression and control – from the same baseline population, and kept them separate for 28 generations. From each generation, she selected the most aggressive flies from the high aggression group, the least aggressive flies from the low aggression group, and a random sample of the control flies, to be the parents of the next generation.
All the flies started at the same level of aggression, but after 28 generations of selection, the high aggression groups were kicking, chasing and boxing more often, while low aggression groups would hardly fight at all.

Hey, these are my neighbors from upstairs. And note how Trudy Mackay knows what to tell the reporter so not to end up with one of those “Gene for X” titles:

Selection experiments only show these kinds of results when there is some genetic control over the trait being selected. In this case, the genetic effect was not very strong – the heritability, or genetic contribution to, aggressive behavior was about 10 percent. The other 90 percent had to be attributed to environmental variation.
“This is definitely not genetic predeterminism,” Mackay said. “It’s a susceptibility. Even in flies, in the constant environment in which we grow them, the environment is more important than the genes. But we are very interested in that small genetic contribution.”

Read the rest, it’s cool…

Bees Gone Wild

Wild Bees Make Honeybees Better Pollinators
How?
By sexual harrassment!
Wild bees behave like the male audience of Girls Gone Wild – obnoxious and aggressive. So, the honeybees keep running away from them – from flower to flower.
Winners: Flowers.
Seriously:

Compared to honeybees, wild bees did not contribute much directly to crop pollination. But on farms where wild bees were abundant, honeybees were much more effective in pollinating flowers and generating seeds, Greenleaf found.
There appear to be two reasons for that. Male wild bees, probably looking for mates, will latch onto worker honeybees, which are sterile females, causing them to move from one flower to another. Secondly, female wild bees appear to “dive bomb” honeybees, forcing them to move. Frequent movement between flowers spreads pollen around more effectively.

“Divebomb!”

But HOW do they do it?

Bird Moms Manipulate Birth Order To Protect Sons:

—————-snip——————-
Since 2002, Badyaev, Oh and their colleagues have been intensively documenting the lives of a population of house finches (Carpodacus mexicanus) on the UA campus.
Throughout the year, the researchers capture birds several times a week to band and measure them and to take DNA and hormone samples. During the breeding season, the researchers locate the nests, keep track of activity in the nest, follow nestling growth and development, and take DNA samples from the chicks.
The researchers have also been counting the numbers of mites on the birds and documented a seasonal pattern. When breeding starts in February, the mites are absent. As winter turns to spring, mites start showing up on the adult females, in their nests and on their nestlings. The exact timing depends on the year.
Mites can kill nestlings.
“When it is safer inside the nest than outside, then there’s no need for young to leave the nest until growth is complete, but when mortality risk of staying in the nest is great, chicks need to complete their growth fast and get out as soon as they can,” Badyaev said. “What should a mother do in the face of shifting mortality risk?”
“To leave the nests sooner and still survive outside of nests, the kids need to grow faster,” Badyaev said. “But the mechanisms which regulate nestling growth in relation to changing mortality were not known.”
So the researchers looked to see how finch moms changed their child-rearing strategy so as to always do best by their kids.
The birds lay one egg per day. To successfully raise baby finches in the presence of mites, the mothers altered the order in which male and female eggs were laid.
When mites were absent, the chances of any particular egg being male or female were even. But once mites came into the picture, the mothers laid female eggs first and male eggs last.
Males that grew during mite season did more of their development in the egg before hatching. Their mothers accelerated their sons’ growth, both in the egg and after they hatched.
“Mothers essentially hid their sons in the eggs,” Badyaev said.
It’s remarkable that the fledglings have such similar morphology with or without mites, he said. “Mothers did that by modifying the order of laying of male and female eggs and the pattern of their growth.”

This is cool ecology and evolution. But where is the physiology, i.e., the mechanism of birth-order of sexes?

Paramecium is such a cool organism to work with!

Paramecia Adapt Their Swimming To Changing Gravitational Force:

The researchers placed a vial with pond water and live paramecia inside a high-powered electromagnet at the National High Magnetic Field Laboratory in Tallahassee, Fla. The organisms are less susceptible to a magnetic field than plain water is, so the magnetic field generated inside the vial “pulls” harder on the water than on the cells. If the field is pulling down, the cells float. If it’s pulling up, they sink.
Using water alone, Valles and Guevorkian were able to increase the effect of gravity by about 50 percent. To increase the effect even further, they added a compound called Gd-DTPA* to the water. Gd-DPTA is highly susceptible to induced magnetic fields such as those generated in electromagnets. This allowed the researchers to make the water much “heavier” or “lighter,” relative to the paramecia, achieving an effect up to 10 times that of normal gravity. The magnetic field is continuously adjustable, so Valles and Guevorkian were also able to create conditions simulating zero-gravity and inverse-gravity.
By dialing the magnetic field up or down, the researchers could change the swimming behavior of the paramecia dramatically. In high gravity, the organisms swam upward mightily to maintain their place in the water column. In zero gravity, they swam up and down equally. And in reverse gravity, they dove for where the sediments ought to be.
“If you want to make something float more,” said Valles, “you put it in a fluid and you pull the fluid down harder than you pull the thing down. And that’s what we basically do with the magnet. That causes the cell to float more – and that turns gravity upside down for the cell.”
Cranking the field intensity even higher, Valles and Guevorkian could test the limits of protozoan endurance. At about eight times normal gravity, the little swimmers stalled, swimming upward, but making no progress. At this break-even point, the physicists could measure the force needed to counter the gravitational effect: 0.7 nano-Newtons. For comparison, the force required to press a key on a computer keyboard is about 22 Newtons or more than 3 billion times as strong.

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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MRI getting smaller (and cheaper)

It’s looking good. Certainly much smaller than the roomful of metal we are used to seeing in hospitals.
Do you remember when computers used to fill entire rooms? Now take a look at your cell phone. Now think MRI in 10-20 years…
See what I’m getting at?
I am patiently waiting for the time when MRIs are small and light enough to be mounted on heads of freely behaving animals (in the wild or in captivity), at least large animals like elephants, dolphins, horses, crocs or sharks… Then you use radiotelemetry to get the info loaded on your computer and you observe the brain activity in real time as the animal is interacting with its environment.
I hope this happens while I am still young and active enough to use such technology in research…

March Of The Penguins, again

Hungry Hyena has an interesting critique of the movie.

Revenge of the Zombifying Wasp

Revenge of the Zombifying WaspOne of the coolest parasites ever (from February 04, 2006):

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Cooperative Hithhiking

Baby bugs team up for sex scam

The moment they’re born, beetles of one species join forces for a curious drill.

The larvae hatch out of their eggs and together, as a group, climb to the tip of the plant. There, they secrete a sex pheromone that attracts a male of a bee who tries to couplate with the ball of larvae. They jump on him. He flies away carrying the little buggers.
When he finds a female to mate with, the larvae jump ship and go away hithhiking on her. When she goes back to her nest they disembark, eat the nectar she collected and her eggs before their final metamorphosis.
Arthropods are known to hitch rides on other animals, including larger arthropods, but this is the first documented case of a group hithchiking together.

Are cryptochromes involved in magnetoreception in migratory birds?

Scientists discover molecule behind birds’ magnetic sense:

“Some birds, notably migratory species, are able to detect the Earth’s magnetic field and use it to navigate. New results from a team of Franco-German researchers suggest that light-sensitive molecules called cryptochromes could be the key to the birds’ magnetic sense.

They did not suggest it – they tested a 10-year old hypothesis.

Cryptochromes are photoreceptors which are sensitive to blue light, and they are involved in a number of processes linked to the circadian cycle, such as growth and development.

Caution: cryptochromes have different functions in different organisms. They are very closely related to photolyases, molecules involved in DNA repair. They are photopigments in plants, but have no circadian function in them. They are involved in circadian phototransduction in insects, but are not pigments and are not clock genes in them. They are core circadian genes in vertebrates, but are not pigments in them. So, we have to be careful when dealing with such a jack-of-all-trades.

Birds’ ability to detect magnetic fields is affected by light; this ‘sixth sense’ only works properly in the presence of blue or green light, while light of other wavelengths disrupts the magnetic sense.

Do you know how much I hate the phrase “sixth sense’?

The scientists realised that the cryptochromes could well be involved in the perception of the magnetic field, as they have all the physical and chemical properties needed, notably the absorption of blue and green light and the formation of ‘radical pairs’ – molecules which respond to magnetic fields. Crucially, the retina of birds’ eyes is rich in cryptochromes.
Unable to test their hypothesis on migratory birds, the researchers turned to a laboratory plant, Arabidopsis thaliana, with similar properties. It is known that the activation of their cryptochromes by blue light influences the behaviour of these plants; for example it inhibits the growth of the hypocotyle (stem).

This is creative, but poses a problem that I mentioned above – in different environments (i.e. inside the bodies of different organisms with different genomes), cryptochromes assume different functions.

To determine whether the magnetic field influences the function of the cryptochromes, researchers from France’s National Centre for Scientific Research (CNRS) and universities in Frankfurt and Marbourg grew the plants in the presence of blue and red light and magnetic fields of varying strengths. They found that increasing the magnetic field only increases the inhibition of the growth of the hypocotyle in the presence of blue light. When red light is used, the plant uses other photoreceptors called phytochromes, and the growth of the hypocotyle is not affected by changes in the magnetic field. Furthermore, mutant plants which have no cryptochromes are also insensitive to changes in the magnetic field.

This is a nice piece in the puzzle, but nothing conclusive yet, of course.

The study shows for the first time that in plants, the work of the cryptochromes is affected by magnetic fields and suggests that the mechanisms of magnetic field perception in plants, and by extension in migratory birds, use the same photosensitive molecules. The researchers also suggest that, as cryptochromes have been strongly conserved throughout evolution, all biological organisms could have the ability to detect magnetic fields, even if they do not use them.”

The phrase “and by extension” worries me for the reasons I noted above.
As for all organisms detecting magnetic fields – yes, decades of research show that most can, from bacteria to, perhaps, even humans. However, this does not mean that cryptochromes are the magnetosensory molecules in all of them, or even that the radical-pair model of magnetoreception applies to all organisms.
It is well established that many organisms do not require the presence of blue-green light in order to orient by he magnetic fields. It is also known that many organisms, from bacteria through salmon to pigeons, possess miniscule crystals of feromagnetite. In bacteria, those form a chain running through the posterior medial line of the cell. In salmon and pigeons, they are embedded inside cell membranes of the dendrites of the trigeminal nerve.
So, cryptochromes may be involved in some way in magnetic sense of some organisms. Extrapolating any broader (i.e., it is the only mechanism; cryptochromes are the main element of the mechanism; this mechanism works in all organisms) is unlikely to be correct. So, the press release is hypoing the work beyond what it really shows. It is good. Actually, it is really cool. But the press release soured me on it.
For an excellent (and quite current) review of the topic, see this review (pdf) and for a moer lay-audience oriented, also quite current article, see this article on The Science Creative Quarterly.

Helping your kids whichever way you can

‘Empty Nester’ Parent Birds Use Recruitment Calls To Extend Offspring Care:

By studying a habituated population of pied babblers (Turdoides bicolor) in the Kalahari Desert, researchers have discovered a surprising new way in which parent birds can extend the period of their care of offspring.
———–snip—————
It is well known that birds feed their young directly, but it is usually assumed that care ends when the young leave the nest and begin to forage for themselves. In many species, however, parents and young continue to associate with one another beyond this point of nutritional independence. Because juveniles are poor foragers, they might benefit from staying close to experienced adults, who can find the best feeding sites.
The new study shows that adult babblers continue to care for their young during this period. By observing the birds closely and performing simple playback and feeding experiments, the biologists found that babbler adults use a special “purr” call to recruit inexperienced fledglings to rich, divisible food sources (adults responding to the calls often met with aggression from the caller). The researchers found that fledglings that responded to this call were much more successful than those sticking to areas chosen by themselves. This work shows that recruitment calls by adult birds may prolong offspring care beyond the onset of nutritional independence, and it sheds new light on the sophistication of parental care among birds.
———–snip—————

Some hypotheses about a possible connection between malaria and jet-lag

Blogging on Peer-Reviewed Research

Some hypotheses about a possible connection between malaria and jet-lagHypotheses leading to more hypotheses (from March 19, 2006 – the Malaria Day):

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More on cannibalism in mantises

If you are interested in the pros and cons of cannibalism in praying mantises, you should check out the latest Carl’s post and article on the topic.

More on Dolphin Intelligence

Chris Chatham of Developing Intelligence blog wrote an excellent summary of the controversy over dolphin intelligence and adds his own thoughts on the matter, with which I agree:

In conclusion, there are countless reasons to doubt that dolphins are “dumber than goldfish,” or indeed that popular musings about dolphin intelligence have been inaccurate. Of course, as Cognitive Daily points out, it is clear that they don’t have human-level intelligence – whatever that may mean. On the other hand, Manger has developed a new theory about the evolution of the dolphin brain; unfortunately, any extrapolation from neuroanatomy to cognition is still highly theoretical, particularly in the case of dolphins, whose brains are so drastically different from our own. Therefore, given the state of neuroscience, judgments of dolphin intellectual powers must more heavily weigh behavioral work (however flawed) than arguments from evolutionary data and cellular neuroscience such as Manger’s.

Read the whole thing.

Social cohesion through consensus about hierarchy

Power Emerges From Consensus In Monkey Social Networks:

Research on communication typically focuses on how individuals use signals to influence the behavior of receivers, thus primarily focusing on pairs of individuals. However, the role communication plays in the emergence of social structures is rarely studied.
In a new paper from The American Naturalist, Santa Fe Institute researchers Jessica Flack and David Krakauer study how power structures arise from a status communication network in a monkey society. Power structure is important because it can influence the complexity of interactions among group members.
“When building a society, it is of utemost importance that signals be informative and any sources of ambiguity minimized,” says Krakauer. “This requirement is reflected in the structure and function of communication networks. A goal of this research has been to study communication at a group level rather than the more traditional communication we associate with pairs.”
Using information theory, the researchers show that power emerges through consensus. There is a high degree of consensus among group members that an individual is powerful if that individual has received multiple subordination signals from many individuals — in the case of pigtailed macaque monkeys, a silent bared-teeth display. On the other hand, there is little consensus if signals come from just a few individuals.
“Consensus about power is an important organizing principle in societies in which conflicts are complicated, often involving many group members at once,” explains Krakauer. “In such cases, only individuals widely perceived as powerful will be able to terminate or reduce the severity of these conflicts. Power structure is critical to conflict management, which is in turn critical to social cohesion.”

Monkey see, monkey do

Chimpanzees Can Transmit Cultural Behavior To Multiple ‘Generations’:

Transferring knowledge through a chain of generations is a behavior not exclusive to humans, according to new findings by researchers at the Yerkes National Primate Research Center of Emory University and the University of St. Andrews, Scotland. For the first time, researchers have shown chimpanzees exhibit generational learning behavior similar to that in humans. Unlike previous findings that indicated chimpanzees simply conform to the social norms of the group, this study shows behavior and traditions can be passed along a chain of individual chimpanzees. These findings, based upon behavioral data gathered at the Yerkes Field Station in Lawrenceville, Ga., will publish online in the August 28 early edition of the Proceedings of the National Academy of Sciences.
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“The chimpanzees in this study continued using only the technique they observed rather than an alternative method,” said Horner. “This finding is particularly remarkable considering the chimpanzees in the control group were able to discover both methods through individual exploration. Clearly, observing one exclusive technique from a previous chimpanzee was sufficient for transmission of behavior along multiple cultural generations.”

Fido, get off the bed!

Do dogs get jealous? At just the most inopportune moments?

So, dolphins are dumb and manatees are smart?

Yesterday, we were putting down media reports on a study that purports that dolphins are not intelligent despite behavioral studies and big brains. Today, NYTimes has a much better article arguing that manatees, despite their small brains, are more intelligent than previously thought.
It is a longish article but well worth reading. The idea is that manatees don’t have too small brains, but overlarge bodies, and, since they are herbivores with no prey or predators, they do not need to reserve vast portions of their brains for tackling hunting and defense.

Brain size has been linked by some biologists with the elaborateness of the survival strategies an animal must develop to find food and avoid predators. Manatees have the lowest brain-to-body ratio of any mammal. But, as Dr. Reep noted, they are aquatic herbivores, subsisting on sea grass and other vegetation, with no need to catch prey. And with the exception of powerboats piloted by speed-happy Floridians, which kill about 80 manatees a year and maim dozens more, they have no predators:
“Manatees don’t eat anybody, and they’re not eaten by anybody,” Dr. Reep said.
But he also suspects that rather than the manatee’s brain being unusually small for its body, the situation may be the other way around: that its body, for sound evolutionary reasons, has grown unusually large in proportion to its brain.
A large body makes it easier to keep warm in the water — essential for a mammal, like the manatee, with a glacially slow metabolism. It also provides room for the large digestive system necessary to process giant quantities of low-protein, low-calorie food.
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Manatees have a relatively thick cerebrum, with multiple layers that may, Dr. Reep suspects, indicate complexity despite a lack of folding.
In any case, he said, brain convolution “doesn’t seem to be correlated with the capacity to do things.”
More to the point, intelligence — in animals or in humans — is hard to define, much less compare between species, Dr. Reep said. Is the intelligence of a gifted concert pianist the same as that of a math whiz? Is a lion’s cunning the same as the cleverness of a Norwegian rat?
The manatee is good at what it needs to be good at.

The rest of the article focuses on manatees’ sensory capabilities, especially the somatosensory system. Manatees have vibrissae (long hairs, usually seen only around the faces of animals like cats and dogs), which are thought to be involved in the sense of touch, spread all over the body. The article incorrectly states that the only other mammal with vibrissae all over the body is rock hyrax. There is another one, though, which is much better studied in this regard – the naked mole-rat.
Also, the article states that manatee is unique among mammals in the ability to hear infrasound. That is also wrong – a lot of mammals, especially large mammals are capable of hearing infrasound. The best studied are elephants and whales, but it was also described in giraffes (von Muggenthaler, E., Baes, C., Hill, D., Fulk, R., Lee, A., (1999) Infrasound and low frequency vocalizations from the giraffe; Helmholtz resonance in biology, invited to the Sept. 2001 AZA conference, presented at the regional Acoust. Soc. Am. conference 2001.) and rhinos, while the infrasound vocalizations were made from okapis, tigers, horses and cows, as well as in some non-mammalian vertebrates, including crocodiles and perhaps some birds.
So, in light of our discussion yesterday, what do you think?

Dolphins Are Intelligent!

Where does one start with debunking fallacies in this little article? Oy vey!

Dolphins and whales are dumber than goldfish and don’t have the know-how to match a rat, new research from South Africa shows. For years, humans have assumed the large brains of dolphins meant the mammals were highly intelligent.

No, we knew dolphins were smart millenia before we ever looked at their brains. The ancient Chinese knew it. Aristotle knew it. And the idea that brain size has anything to do with intelligence is, like, sooo 19th century.

Paul Manger from Johannesburg’s University of the Witwatersrand, however, says it is not intelligence that created the dolphin super-brain — it’s the cold. To survive underwater, these warm-blooded animals developed brains that have a lot of insulating material — called glia — but not too many neurons, the gray stuff that counts for reasoned thinking.

Wow! Since when are glia “insulating material”? A few years ago, for my Neuroscience class, I had to remember at least 10 functions of glia – not one of them having anything to do with insulation, or even structural support. It’s all about function – neurons and glia work together to process information. Anyway, I will blame this on the stupidity of the reporter as I doubt that anyone with such archaic ideas would ever be allowed to dissect a dolphin and publish a study in a decent journal.

Yet while dolphins aren’t as smart as people tend to think, they are as happy as they seem. Manger said dolphins have a ”huge amount” of serotonin in their brains, which is what he described as ”the happy drug.”

Sure, if you get your science from Cosmo and Glamour. Do I really have to start listing all the functions of serotonin now? Or try to define “happiness” in such simplistic terms that it can be explained with a single chemical?
It is not quite clear, but it appears that Alon Levy agrees with the study. But Lindsay is having none of it. She cites the self-recognition paper as well as some personal testimony of the researcher who did that study. When that paper came out I was teaching a “Readings in Behavioral Biology” graduate seminar and all the neuro faculty showed up for class and tried valiantly to destroy the paper – with no avail. It is good.
Dolphins are darn smart. They play (check this pdf). They have complex communication and complex social interactions.
So, how does this kind of argument ever show up? Because of anthropocentrism. Two types of anthropocentrism, to be precise.
First, the concept of “intelligence” is often defined in human-like terms. If an animal can do stuff we do, it is deeemed smart. If it can be easily trained like our immature offspring can, it is smart. If it can talk, it is smart. If it builds structures, it is smart. BS. Intelligence has to be defined from the vantage point of that species: what makes ecological and evolutionary sense for that species to be able to do. Bees are smarter than ants because they have a more sophisticated ability to orient in space and time, not because they speak English, French and Chinese.
Now, don’t get me wrong now. Since we are intelligent, looking for intelligence in other animals may benefit from comparison to humans. The trouble is, people go for specifics of human capabilities, instead of a general idea what intelligence is.
Writing “Hamlet” is an ecologically relevant ability for humans. It kept old Will fed and clothed for a few months, after which he wrote the next play. Why would an insect need to write theater plays? It is not ecologically relevant to it. It does not aid survival and/or reproduction.
Intelligence is the ability to learn fast and learn a lot of pieces of information relevant to one’s ecology. It is the ability to hold many of those pieces in one’s mind simultaneously, to juggle them and analyse them and notice patterns. It is the ability to play with that information, to get new ideas and test them, to note and remember the results of those tests. It is the ability to use this novel informaiton to invent novel behaviors – doing different stuff at different places at different times. In short, intelligence is the ability to do science! Behavioral flexibility is the hallmark of intelligence – not the specific types of behaviors.
The second anthoropomorphism considers the underlying anatomy. Why should unrelated species of high intelligence have brains similar to us? They evolved their high intelligence at different times, in a different lineage, with different raw materials to work with, and under different ecological pressures, for different purposes.
Many birds are very intelligent – but in their own way. Clarke’s Nutcrackers, African Grey Parrots, pigeons, and most corvids (ravens, crows, jays) are highly intelligent creatures with huge capabilities for episodic memory (remembering spatial and temporal aspects of personal experiences), play, problem-solving, spatial orientation and perhaps even insight (planning for the future). And their brains look nothing like ours.
Octopus is a very smart animal. Its brain looks nothing like ours.
Macs and PCs can do all the same stuff (roughly), but look nothing like each other under the hood. Many kinds of harware can run the same kinds of software and do same kinds of things, so why should brains have to be all built the same way in order to make an animal “intelligent”?
So, leave the dolphins alone, at least until the Startide Rising.
Addendum: I forgot to note that glia are not white matter. Axons are white matter while neuronal bodies are grey matter. Glia surround both. It is the color of Schwann cells (a type of glia) that makes axons look whitish.
Thus, more grey matter means more neurons. More white matters means more connections. What is more important: gazillions of scattered cells, or the complexity of their connections? I’d say connections.
Addendum II: Dave Munger wrote a valid criticism of what I wrote here (and somehow I missed his earlier post on this subject):

I agree that intelligence is tremendously difficult to define, but I’d suggest that the perspective of an individual species is a poor place to start. Based on that notion, every organism can be said to be intelligent, because every organism is highly adapted to its environment. When we say an animal is “intelligent,” we’re defining intelligence from our own perspective: the point is to identify animals that are similar to ourselves.

I’m not sure that the point is to identify animals that are similar to ourselves, but even if it is, similar in what way? The general mental capabilities (that we still need to define) or specific capabilities (which I argued here against)?
As for looking at each species individually, I agree that it is impossible to do it in isolation, but eahc species can be compared with other species in its own group, e.g., birds with birds, insects with insect, and then broader, all with all. If we define, provisionally, intelligence as fast learning, high processing power and flexibility of behavior, then we can compare species without looking at specific items that are learned, specific informaiton that is processed and specific behaviors that are flexible. For some species, being inflexible is a great adaptive trait – doing everything by the pre-programed schedule can work wonderfully for a long period of time. Other species evolve flexibility which allows them to spread on a broader spatial range and perhaps allow them to survive a longer geological time.

Books: “The Cultural Origins of Human Cognition” by Michael Tomasello, part II

CogBlog - Tomasello: Chapter 2 The review of the second chapter was written on September 06, 2005:

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Listen to the Song of the Orca

Every now and then, David Niewert takes a break from discussing Far-Right White-Supremacist groups and writes a beautiful post on orcas (after all, Orcinus blog has been named after these beautiful whales). Here’s the latest.

So, elephants actually run (leave the ground with all four feet at the same time)

Have You Ever Seen An Elephant … Run?:

Dr John Hutchinson, a research leader at the UK’s Royal Veterinary College (RVC), has already shown that, contrary to previous studies and most popular opinion, elephants moving at speed appear to be running. Now with funding from the Biotechnology and Biological Sciences Research Council (BBSRC) his team is using Hollywood-style motion capture cameras combined with MRI and CT scans of elephants to build 3D computer models of elephant locomotion to show the forces and stresses at work on muscles, tendons and bones.
The research team has been working with elephants at UK wildlife and safari parks and will shortly travel to Africa and Thailand to study wild animals. Fifteen temporary markers are placed on the elephants’ joints and the animals then move past a motion capture camera, recording at 240 frames per second, at varying speeds. Back in the lab the researchers can then use the footage to reconstruct the rotations of the elephants’ joints on a computer, creating a 3D stick model of the animal.
The computer models are being used to establish how limb structure relates to elephant locomotion and to determine finally if elephants really can run – or in scientific terms, at some point do they have all their feet off the ground at the same time? Dr Hutchinson said: “We are particularly interested how elephants coordinate their limbs and working out which joints contribute most to the length and frequency of their steps. In examining whether elephants truly run or not we need to understand what limits their top speed. Is it the tendons and muscles having to withstand the impact of 7 tonnes of elephant or is it something else?”

Read the whole thing. I love this kind of stuff! I remember when, back in the late 1980s, I first saw a study (from Bulgaria, I believe) done like this – of a horse jumping over a fence. Way cool!
Next step – how do elephants fly! Certainly you’ve heard the old true-life anecdote:
Two elephants are sitting on a tree. A third elephant flies by. The first elephant turns to the second elephant and says: “Hmmm, I bet her nest is close by”
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Why hibernating animals occasionally wake up?

One of the several hypotheses floating around over the past several years to explain the phenomenon of repeated wake-up events in hibernating animals although such events are very energy-draining, is the notion that the immune system needs to be rewarmed in order to fend off any potential bacterial invasions that may have occured while the animal was hibernating:

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Clock Tutorial #15: Seasonality

Clock Tutorial #15:  SeasonalityThis post (click on the icon) was originally written on May 07, 2005, introducing the topic of neuroendocrine control of seasonal changes in physiology and behavior.

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Eye Color

Carel discovered a fascinating website about iris pigmentation. As Carel notes:

Morgan Worthy, a retired psychologist, has put together an iris pigmentation site that includes lists of iris color for over 5,600 vertebrate species, along with observations based on his database that range from the insightful to the mundane to the crackpottish.

There are hypotheses there concerning eye color in humans and in animal predators. Looks like a treasure trove of material for blogging when you are out of inspiration and especially if you are wondering what to send next for the Skeptic’s Circle.

Global Warming disrupts the timing of flowers and pollinators

As the temperatures rise, different organisms respond differently. Some migrate to higher latitudes or altitudes. Others stay put but change the timing of reproduction and other seasonal activities. As a result, ecosystems get remodeled.
So, for instance, insect pollinators and flowers they pollinate may get out of sync.
Animals tend to use photoperiod as a major clue for seasonal timing, with temperature only modulating the response to some extent.
Plants, on the other hand, although they certainly can use photoperiod, are much more strongly influenced by temperature. Non-biologists who have only heard abot vernalization in the context of discussion of Lysenko may not be aware that this process is not bunk pseudoscience, but a target of active research:

Flowers are the reproductive organs of plants and are responsible for forming seeds and fruit. As their name implies, biennials complete their life cycles in two years, germinating, growing and overwintering the first year. The second year, the plants flower in the spring and die back in the fall.
That biennial strategy, Amasino explains, arose as flowering plants, which first evolved some 100 million years ago during the age of the dinosaurs, spread to fill the niches of nature. Spring blooming confers numerous advantages, not the least of which is leafing out and flowering before the competition.
But how do the plants know when to flower?
“If you carve out that niche, you need to get established in the fall, but you need to make darn sure you don’t flower in the fall,” Amasino says. In the case of biennials, “the plants can somehow measure how much cold they’ve been exposed to, and then they can flower rapidly in the spring niche.”
Exposure to the cold triggers a process in plants known as vernalization, where the meristem – a region on the growing point of a plant where rapidly dividing cells differentiate into shoots, roots and flowers – is rendered competent to flower.
In a series of studies of Arabidopsis, a small mustard plant commonly used to study plant genetics, Amasino and his colleagues have found there are certain critical genes that repress flowering.
“The plants we’ve studied, primarily Arabidopsis, don’t flower in the fall season because they possess a gene that blocks flowering,” Amasino explains. “The meristem is where the repressor (gene) is expressed and is where it is shut off.”
The key to initiating flowering, according to the Wisconsin group’s studies, is the ability of plants to switch those flower-blocking genes off, so that they can bloom and complete their pre-ordained life cycles.
But how that gene was turned off was a mystery until Amasino and his group found that exposure to prolonged cold triggered a molecular process that effectively silenced the genes that repress flowering.

So, if the plants respond to temperature by changing the timing of flowering and insect retain the same timing (although they mave migrate away), there will be no flowers around when the insects are looking for them, and no insects buzzing around when the flowers need to be pollinated.
This recently got some experimental support:

“Climate change is already affecting ecological systems and will continue to do so over the coming years, providing a particularly relevant topic for this session,” said Inouye.
For instance, Earthwatch volunteers in the Rocky Mountains helped Inouye document that global warming affects lower altitudes differently than higher ones. As a result, animals exposed to earlier warm weather may exit hibernation earlier and birds responding to earlier spring weather in their wintering grounds may flock north while there are several feet of snow on the ground, risking starvation.
“Already the difference in timing between seasonal events at low and high altitudes has negatively influenced migratory pollinators, such as hummingbirds, which overwinter at lower altitudes and latitudes,” said Inouye. “If climate change disturbs the timing between flowering and pollinators that overwinter in place, such as butterflies, bumblebees, flies, and even mosquitoes, the intimate relationships between plants and pollinators that have co-evolved over the past thousands of years will be irrevocably altered.”

Clockwise or counter-clockwise?

Gray Birds Cover 40,000 Miles Annually:

“Sooty shearwaters may not look like much, but when it comes to travel they put marathoners, cyclists and pretty much everyone else to shame.
These gray, 16-inch birds cover 40,000 miles annually in search of food, the longest migration ever recorded electronically, according to a report in this week’s online edition of Proceedings of the National Academy of Sciences.”

How does that compare to Arctic Terns and their pole-to-pole migration? Or the east-west migration of some ptarmigans from Scandinavia to Kamtchatka and back?

“The birds, which can have a wingspan of 43 inches, followed a figure-eight circuit over the Pacific Ocean. They ranged north to the Bering Sea, south to Antarctica, east to Chile, and west to Japan and New Zealand, covering over 40,000 miles in 200 days, the researchers said.”

Figure of eight? That is an unusual pattern. Is it really a migration in a traditional sense (between summer/breeding and overwintering grounds), or is it more like nomadic flying around in a predictable trajectory?