LSM1303 Animal Behaviour

In past researches on dogs, it is almost believed that yawning in dogs is not a sign of tiredness but rather an indication that the dog is suffering stressing conditions from the surroundings. This is because yawning is able to increase heart rate and blood flow to the brain and helps to fill the lungs with oxygen. Thus, yawning helps a dog to energize its body and stays alert to respond to potential threats.

However, due to close socialization between human and our domestic canine buddies over thousands of years, man could affect how dogs behave and react overtime. A team led by Dr Senju, conducted an experiment and concluded that although at times, yawning in dogs is a response to extreme stress, the true reason for why contagious yawning is catching is not fully understood for now. However, a reason for dogs’ yawnings could be due to the fact that they have the capacity for a fundamental form of empathy towards human beings. 

Am I tired? or am I not?

To further the research, the team created two conditions. For the first experiment, a stranger sat in front of the dog and calls its name. “We gave dogs everything: visual and auditory stimulus to induce them to yawn.” said Dr Senju. Under this condition, the stranger yawned once the dogs had made eye contact with them. As for the second condition, the auditory stimulus was taken off as a precaution to ensure that dogs were not responding to an open mouth. Out of 29 dogs from a wide range of dog breeds, 21 of them responded to the yawning, while no dogs yawned during the non-yawning scenarios.

The experiment

“There are theories that seem to think that we used to transfer this information of ‘I am tired’ by yawning when we didn’t have language,” Joly-Mascheroni told LiveScience. In a way, humans could be indicating sleepiness to dogs. “It would be interesting to find out what other information we transfer to dogs or to any other animals that we are not aware of,” he added.

With great curiosity, I have conducted my own “yawning induction experiment” on my dog Happy. Like what was stated as the conditions, I called her name, waited for her to make eye contact with me and yawned with action and sound. Happy could not be bothered with me for the first time but responded upon the second trial!

Go ahead! Try yawning to your dog next time and see what happens!

            References:

1)     Pet dogs can ‘catch’ human yawns, http://news.bbc.co.uk/2/hi/science/nature/7541633.stm, by Jennifer Carpenter,  BBC new, 5 August 2008

2)     Dogs Catch Human Yawns, http://www.livescience.com/animals/080917-dogs-yawn.html by  Jeanna Bryner, 17 September 2008

3)     Dogs can ‘catch’ yawns too, http://www.brudirect.com/DailyInfo/News/Archive/Aug08/080808/wn01.htm, retrieved on 13.4.2009

4)     Dog Body Language, http://www.justusdogs.com.au/dog-pages/all-about-dogs/552/dog-body-language.cfm, retrieved on 13.4.2009

Predator-prey relationship is extremely crucial in upholding the delicate balance among different animal species. Prey and predators alike are constantly undergoing adaptive changes to aid in their survival. To avoid falling prey to a predator, animals have developed various types of defense mechanisms and methods of accessing predator risk factor. For the red-eyed treefrogs, Agalychnis callidryas, it appears that even their embryos are able to respond to predator threat.

Nora, an adopted grey tabby, has won fame for playing the piano. This rare behavior was apparently self-taught or innate, when she climbed on top of a Yamaha Disklavier piano in the middle of the night and began to play. The couple who adopted Nora owns an art and music studio, where students play the piano in the day. The owners of Nora observed that she has a preference to play on the Yamaha Disklavier piano, even though there are other pianos in their studio. She also includes black keys in her music (http://www.youtube.com/watch?v=TZ860P4iTaM), and plays duets with the students (http://www.youtube.com/watch?v=v0zgQAp7EYw).

From both videos, it does seem like Nora is musically inclined and not just “fooling around” with the piano. Is her sense of music innate or is there some other reason for her bahavior? A 2001 National Geographic article “Do Animals Have an Innate Sense of Music” suggests that animals, including birds and mammals like whales use many musical concepts, such as rhythm, phrase lengths and song structure in their communication. This may help to explain Nora’s sense of rhythm when playing the piano.

However, a piano is an unnatural musical instrument for an animal. Although the owners claim that Nora is self-taught, one might think it’s more probable that Nora might have went through “observational learning”, where the owners taught students to play the piano in the day when Nora was around. Since Nora was also described as being attention loving, the huge amount of attention thrown onto her following her piano-playing incident might have served as a positive reinforcement for her to do it again.

While the rare behavior of Nora has yet been explained satisfactorily, it is most reasonable to suspect that an interplay of the cat’s innate musical abilities and subsequent learning through observation can account for the phenomenon.

References

“Do Animals Have an Innate Sense of Music?”, by Jen Mapes. National Geographic, 05 Jan 2001.

“Nora (Cat)“, Wikipedia. Date accessed: 12 Apr 2009.

The Stoat or more commonly know as the Ermine or the Short-tailed Weasel, is a a small mammal of the family of Mustelidae. It can be found in the Northern temperate, sub-artitic and Artitic regions, as well as Europe, North America and Asia. It is a predator and a carnivore and it feeds mostly on small mammals such as rodents, fish and reptiles. It also prey on larger mammals than itself such as rabbits.

One of the most interesting behavior about the Stoat is the way in which it hunts larger mammals than itself such as rabbits by performing a sort of dance to transfix the rabbit, and the rabbit appears to be hypnotized by it and fail to realise that the Stoat is within striking distance, and falls prey to it!

Here is a link to an article where you can read about real life descriptions of how people observed stoats hunting their prey http://www.forteantimes.com/features/articles/88/stoat_packs.html

Here is a video of the Stoat performancing the dance!

Stoat Dance

Here is another video of how the stoats hunt its prey once it got within striking distance

Stoat Hunting

There are some explanations for the behavior of Stoats doing the dance. Scientist attribute it to, them trying to gain the curiosity of the animal, thus enabling them to more easily preying on it, and that it is a learned behavior as Stoats being opportunistic hunters, when they learned the connection between mesmerizing the animal and the subsequent kill.

However other proponents of the theory have suggested that it could be due to the intense irritation of parasitic worms lodged in the Stoat’s skull, which led to such behavior.

You can read more about the reasons for the dancing behavior of Stoats in this scientific article: http://books.google.com.sg/books?id=5ae9c7GO_cUC&pg=PA120&lpg=PA120&dq=stoats+dance+hunting&source=bl&ots=M6pDak3C-u&sig=AgHaWPlUPiBbc85Bl3aK5moJGuw&hl=en&ei=5XThSe_bJMqLkAXSpdXdCw&sa=X&oi=book_result&ct=result&resnum=1#PPA120,M1

Hope you guys enjoyed this interesting hunting behavior of the Stoats as much as I did! Have a good day!

We are well familiar with the Eiffel Tower, Sydney Opera House and even the Great Wall of China. But as impressive as these human architectures are, we have equally (or some would say, even better) awesome architects in nature: the Termites.

Certain species of Macrotermes and Amitermes build huge mound nests which are more than 10m in height. Amitermes are also known as magnetic termites due to the way they orientate their flat and broad protruding mounds which are along the north and south axis of the Earth. Unlike us, in which we can employ the help of heavy machinery and tools to aid in construction today, the termites built their enormous mounds solely relying only on their own strength. Bit by bit, each worker places a “brick” of building material, consisting of nothing but the soil in their vicinity, probably mixed with a bit of their saliva for cementing purposes.

Why the high and conspicuous mound you might ask. The reason is ventilation. Nests like these house large colonies of termites, some reaching a population of a million strong. With such numbers in an enclosed place, it can get truly hot. Acting as a chimney, the protrusion draws away heat and exchanges it with cooler fresh air. In addition to a chimney, these mound nests are fully equipped with a “well’ at the bottom in which the termites draw precious water.

The designs of these mounds serve several functional purposes like thermoregulation, ventilation and hydration. Moulded and fine-tuned overtime through evolution, they stand the trial of time. It is indeed fascinating to see such elaborate structures constructed by these little creatures working in great unison with such efficiency. But exactly how it is they communicate to each other to achieve such cooperation to the most minute of details, we don’t yet know.

 BBC Home Making: Termites

Termite World – Life in the Undergrowth – BBC Attenborough

References

Korb, J. and Linsenmair, K. E., 2000. Thermoregulation of termite mounds: what role does ambient temperature and metabolism of the colony play? Insectes Sociaux, 47:357-363.

Korb, J., 2003. The shape of compass termite mounds and its biological significance. Insectes Sociaux, 50: 218-221.

BBC Home Making: Termites. Accessed 9 April 2009.

http://www.youtube.com/watch?v=ld07xdqnytk

BBC – Life in the Undergrowth: Episode 3. Accessed 9 April 2009

http://www.youtube.com/watch?v=xGaT0B__2DM

Human is sensitive creature. We use our eyes in communication, and every year a number of people win some acting awards because they possess a pair of extraordinary eyes. Can animals “talk” using their eyes?

No, intelligent animals such as chimpanzee and dog are insensitive to staring or eye-movement. They depend on other forms of communications such as body orientation or movement.

Yes, jackdaw can!

Recent (very recent!) paper published in Current Biology suggested that jackdaw could react to humans watching them. In the report titled “Jackdaws Respond to Human Attentional States and Communicative Cues in Different Contexts”, von Bayern and Emery found that hand-reared jackdaws took significantly longer to retrieve food if a human was staring at the food as compared to the person looking away from the food. Jackdaw would not react so if it “know” the human and hence perceived that he/she is not dangerous.

In addition, the bird was shown to be able to find food through eye movements and hand gestures from the human. Static communication such as an unmoving stare however was uncomprehensive to them. The paper suggested that the sensitivity of jackdaw towards human stares could be due to “a natural tendency to attend to conspecific’s eyes or the effect of intense human contact during socialization”

Mongabay.com quoted the author von Bayern saying that “Jackdaws, amongst many other birds, form pair bonds for life and need to closely coordinate and collaborate with their partner, which requires an efficient way of communicating and sensitivity to their partner’s perspective.” and hence he suggested that we could have underestimated the “psychological realms of birds”.

Jackdaw (Corvus monedula) is one of the smallest species within the genera Corvus, which also includes crow and ravens. Its eyes, as shown in this picture, are similar to human eyes, which has dark pupil surrounded by white iris, perhaps this is why they understand human’s stare?

An article in year 2006 aiming to explore under-studied food sharing behaviours between unrelated individuals outside of courtship in corvids, suggested that juvenile Jackdaws would actively share foods among a number of individuals, regardless of sex and kinship. The article attributed 2 functional explanations to this behaviour, reciprocity and harassment avoidance.

References:
von Bayern Auguste M.P. ,  Emery Nathan J. (2009) Jackdaws Respond to Human Attentional States and Communicative Cues in Different Contexts, Current Biology.
de Kort Selvino R., Emery Nathan J., Clayton Nicola S. (2006) Food sharing in jackdaws, Corvus monedula: what, why and with whom? Animal Behaviour 72(2):297-304.

The humble dung beetle , destined for a lifetime of shit has now expanded its diet to include chomping on live millipedes!

Scientists from Peru have recently discovered a particular species of dung beetle (Coleoptera: Scarabaeidae), Deltochilum valgum, which is the first of its kind to display predatory behaviour, using its modified head and sharper “teeth” to decapitate live millipedes and slice up ther rest of the body for feeding.

Using infrared cameras, the research team led by Dr. Trond Larsen were able to catch live footage of the nocturnal dung beetles in action. Dung beetle heads are normally flat and shovel-like, useful for burrowing in a dung pile. However, D. valgum has a much narrower and pointy head, adapted to get inside the millipede’s body and feed on its insides. The sharper ‘teeth’ they posses are also useful in severing the head of the millipedeand cutting up the body into smaller pieces.

Talk about ferocious!

watch?v=VjLfcHTwr6E
Supplementary material video accompanying Biology Letters article ‘From coprophagy to predation: a dung beetle that kills millipedes’.
Such behaviour intrigues scientists as there is a huge jump from coprophagy (dung feeding) to carnivory. They hypothesise that this unusual evolutionary transition was driven by the high levels competition for food.

This extraordinary behaviour of carnivorous dung beetles is certainly one which will change the way we view the humble dung beetle!
For more information:

Larsen, T., Lopera, A., Forsyth, A. & Genier, F. 2009. From coprophagy to predation: a dung beetle that kills millipedes. Biol. Lett. 5 : 152-155

BBC News “Little dung beetle is big chopper”. Accessed 8th April 2009. (http://news.bbc.co.uk/2/hi/science/nature/7840404.stm)

The work of Desmond Morris fascinated me ever since I got hold of a copy of “The Naked Ape” from the school library and read it in hiding since it was not considered kid stuff at that time. I have been collecting his books ever since.

Apart from his multitude of books about human behaviour, there are few purely animal behaviour books including Animal Watching, Cat Watching and Dog Watching. Desmond Morris born in 1928 is most famous for his work as a zoologist and ethologist, but is also known as an author.

He achieved fame in 1967 with his book “The Naked Ape”. The book is a bold look at the human species focusing on humanity’s animal like qualities and our similarity with apes, and for explaining human behaviour as largely evolved to meet the challenges of prehistoric life as a hunter-gatherer. His later studies, books and shows have continued this focus on human and animal behaviour, explained from a bluntly zoological point.

Reference

The Illustrated Naked Ape: A Zoologist’s Study of the Human Animal. Desmond Morris. Review by Janet Dunaif-Hattis. American Anthropologist. Sep 1987, Vol. 89, No. 3: 732–733

Morris, D. (1996). The Human Zoo. Kodansha America Inc. ISBN 1-56836-104-1

It’s that time of the year again, when the waters to the south of Singapore bristle with excitement and some hot, steamy action. A few days after the full moon in less than a weeks’ time, just after nightfall… the activities will begin. Hordes of fish will gather in frenzy because they can sense the upcoming action. While the corals prepare for a mass orgy, the fish prepare for a huge buffet. Soon the corals become swollen, and then pink bundles burst out from each of the coral polyps, releasing millions and millions of eggs and sperm into the water.

What’s going on? The corals do it. So do the giant clams, sponges and a whole lot of other marine organisms that are quite immobile as adults. Because they are immobile, these organisms exploit the aqueous environment that they live in to help them mate; They release their eggs and sperm into the water, a process termed broadcast spawning, which allows the eggs and sperm to fertilize externally and produce motile larvae for the propagation of the species. To view an awesome video clip of a spawning coral, please click on the link entitled “Coral Spawning” here.

For many species of the hard corals, synchronous mass spawning has been documented all over the world, with that from the Great Barrier Reef in Australia being one of the most well-documented, but this actually occurs in Singapore (Guest et al., 2002) too! Although we do not get thick mats of spawn slick here in Singapore, it is still one of the most breathtaking events on the reef here, THE annual mass spawning of corals, where multi-species of corals spawn in synchrony.

Now broadcast spawning allows for efficient mixing of the gene pool, but why would different species do it together?? The highly nutritious eggs attract hordes of fish that could easily deplete much of the coral babies. By producing an over-abundance of spawn at one go, the predators are overwhelmed, thereby increasing the chances of survival of each coral baby. Simply imagine you are at a buffet, with a great spread in front of you. No matter how delicious the food is, there is only so much that one can consume at a go! This spares the rest of the coral larvae (a.k.a. fish food), till they are ready to settle down and grow into an adult coral colony.

So if you decide to go swimming in the sea in the next few weeks, expect the water to be a little more turbid or have a different smell, and you might also see more schools of fish out in their feeding frenzy!

References
Guest, J.R., Baird, A.H., Goh, B.P.L. & Chou, L.M. 2002. Multispecific, synchronous coral spawning in Singapore. Coral Reefs, 21: 422-423.

The flocking behavior of thousands of starlings, flying in incredible aerial formations, to their roosting sites before settling into trees for the night never fail to amaze by-standers. Collective animal behavior of large groups of animals, such as bird flocks, fish school and mammal herds, is a fascinating natural phenomenon. The main goal of collective behavior among individuals is to maintain cohesion of the group. This cohesion is an important requirement for survival: small groups and individuals are significantly more susceptible to predation than animals belonging to large and highly cohesive aggregations. For example, when a flock of starlings is under attack by a falcon, the flock contracts, expands, and even splits. Despite continuously changing its structure and density, no bird remains isolated, and soon, the flock reforms as a whole.

A common starling, sturnus vulgaris

A group of starling in 'aerial display'

The question to answer is: what kind of interaction enables the birds to maintain cohesion in such a robust way? One proposed theory is that individuals align and attract each other base on metric distance [Couzin et al (2002)] which they can estimate by stereovision, retinal image size and optic flow [Goodale et al (1990)]. This means that such interaction would decay when distance between individuals is increased. For example, 2 birds 5metres apart would attract each other less than 2 birds separated by 1metre in between them. However, if such interaction is based on metric distance, changes observed during predator attack cannot be explained. This is because one would expect the loss of cohesiveness of the flock when metric distances between individuals become larger than the interaction range.

An alternative hypothesis has been proposed [Ballerini et al (2008)] regarding collective behavior: individuals attract each other based on topological interactions. This means that each individual interacts and tracks a fixed number of neighbors despite their metric distance. In this case, 2 birds in a sparse flock and separated by 5metres would attract each other as much as 2 birds in a denser flock and separated by 1metre in between them, provided the number of individuals between the 2 birds is the same. The strength of interaction would thus remain the same for flocks at different densities, enabling the flock to stay together during strong density fluctuations (for example in predator attacks).

To test this hypothesis, Ballerini et al (2008) observed and reconstructed the 3D positions of individual birds in flocks of a few thousand members using stereo-metric and computer vision techniques. Computational numeric simulations were also conducted to test the topological hypothesis with the metric distance hypothesis. The research group concluded that cohesion in flocks, interacting based on topological cues, are much more robust under perturbations than metric ones, and that topologically, each bird interacts on average with six to seven neighbors.

In conclusion, collective animal behavior is an interesting phenomenon which allows large groups of animals to maintain cohesion that is necessary for survival. However, the underlying principles of interaction between the animals are still not fully elucidated, and might be attributed to topological cues between individuals.

References:

ID Couzin, J Krause, R James, GD Ruxton and NR Franks. (2002). Collective memory and spatial sorting in animal groups. Journal of Theoretical Biology 218: 1–11.

MA Goodale, CG Ellard and L Booth. (1990). The role of image size and retinal motion in the computation of absolute distance by the Mongolian gerbil (Meriones unguiculatus). Vision Res 30:399–413.

M Ballerini, N Cabibbo, R Candelier, A Cavagna, E Cisbani, I Giardina, V Lecomte, A Orlandi, G Parisi, A Procaccini, M Viale and V Zdravkovic. (2008). Interaction ruling animal collective behavior depends on topological rather than metric distance: evidence from a field study. Proceedings of the National Academy of Sciences, U.S.A. 105: 1232–1237.