LSM1303 Animal Behaviour Student Blog : adaptive behaviour

Raccoons - Rascals or Ninjas?

Lee Wan Jing — Fri, 21 Mar 2008 15:39:00 GMT

Raccoons - are they cheeky grinning rascals or skillful ninjas of the night?

Image by OCPetPhotos and Sara Heinrichs

First and foremost, racoons (procyon lotor) are noctural animals, and increasingly abundant inhabitants of suburbans areas and cities as humans have destroyed their natural habitats. They are extremely adaptable and can be found in many different kinds of habitats such as wooded areas near water bodies, trees, to woodchuck burrows, caves, sewers, garages and houses, and so on.

Image by k e v i n, kjdrill, dazed81 and secretsamba

The raccoons are omnivorous and their diet consists of a wide range of food, from berries, corns, walnuts, to fish, insects, rodents and in suburban areas, foraging leftovers in garbarge cans and even stealing food from houses, and at times, "begging" for food from passerbys (watch videos below). An interesting note on the raccoon's eating habit (no, they don't sing before they eat nor say grace, nor wipe their hands before they eat)

Image by OCPetPhotos

is that if water bodies are near, they dabble their food in the water as if washing their food in order to clean it, but it is not. The raccoon is simply just softening the food and perhaps at the same time looking for foreign objects/particles on the food (survival skills).

Video 1 - The Night Raiders
note* their eyes - being nocturnal creatures, they have excellent night vision, and they are also especially alert (fine sense of hearing)

Video 2 - Adaption to urban habitat (and humans)
note* they have adapted to the city, and learned to associate humans with food!

Video 3 - More raiding

note* how they used their paws to grab food! using their grasping hand-like paws, they have learned to open garbage cans and gates as well as getting hold of food

Video 4 - a closer view of their paws
note* their paws have five toes that looks a little like our hands and it is flexible and very good, not only at grabbing things, but as pulling things apart and holding things. Very handy indeed! That makes them excellent climbers too, climbing up trees, houses, fences and gates with great agility!

Given their physical appearance, a black mask around its eyes, it gives them the mischievious look of a burglar/ninja indeed.

References

1. http://animaldiversity.ummz.umich.edu/site/accounts/information/Procyon_lotor.html
2. http://teacher.scholastic.com/dirtrep/animal/raccoons.htm
3. http://www.massaudubon.org/Nature_Connection/wildlife/index.php?subject=Mammals&id=26
4. http://www.nhptv.org/natureworks/raccoon.htm
5. http://www.raccoonlearningzone.com/index.php
6. http://www.backyardnature.net/raccoons.htm

Of Bionic Buildings and Animal Engineering

CHONG NIGEL BENEDICT — Thu, 20 Mar 2008 18:42:00 GMT

Introduction

Have you ever wondered why certain species in this world have been able to last and survive in extremely harsh climates? Is it due to advanced biology and/or the way they react with the environment? While the debate on global warming may be a controversial issue, there is little doubt that climate change is occurring. While much has been written about animal behavior, this article takes a different perspective in that it looks at the adaptations of the termite and, more importantly, their mounds, in the environment, and what we can glean from their adaptations.

Termite mounds

A typical termite mound can vary extremely in height, and have a diameter as large as 30 meters. The termites of Sub-Saharan Africa build mounds with the remarkable ability to regulate and control temperature (no more than 2 degrees celcius variation throughout a 24 hour period), maintaining similar ‘comforts’ to our own and, more importantly, respond to the weather and adapt accordingly to the external conditions.

How?

Termites have an extremely specialized caste system that has allowed them to focus on their assigned tasks. The workers are the mound builders (among other things), and centuries of evolution have enabled them to construct mounds that contain mirco-climates unaffected by harsh external weather. They are able to do this by forming ‘complex ducts and channels which not only look like our own vessels and respiratory channels, but function as effectively as well’. Thus air from the outside is brought in to replace stale and warm air on the inside. This tidally ventilated system is ‘driven by dynamic pressures generated by the chaotic fluctuations of wind speed and direction which are common in the turbulent outdoor environment’.

Have you ever noticed that as more people enter a room, the room gets even hotter, and you tell someone to open the window, turn on the fan or air-condition? This increase in temperature is due not only to increase accumulated body temperature, but also a rise in respiratory gases as well. Their ventilation system is able to exchange fresh air from the outside with stale respiratory air via surface ducts and conduits, density variations, a forced convective regime and evaporative cooling. Even more important is the colony’s ability to ‘match the rate of wind-induced ventilation exchange to the colony’s rate of respiratory gas exchange, brought about through adaptive modification of mound architecture’. Thus the termites are not only able to deduce that a colony has increased in size, but also able to match and counter the increase in respiratory gas with concurrent mound growth. How they are able to do this is thus far unsolved.

Examples

Perhaps the first building that encompasses this ‘technology’ on so sophisticated a level is the Eastgate Centre in Zimbabwe, which is totally naturally ventilated and regulated.

Conclusion

Thus looking at certain animals and how they have adapted with the environment can teach us valuable lessons beyond simply discovering processes and understanding animal motivations. We can learn from their ability to survive and adopt practices that can subsequently ensure our own survivability and reduce our ecological foorprint.

References

The Sandkings: http://www.sandkings.co.uk/ (Retrived: 17 October 2007)

Treehugger: http://www.treehugger.com/files/2006/08/biomimetic_buil_1.php (Retrived 17 October 2007)

Insecta Inspecta World: http://www.insecta-inspecta.com/termites/macrotermes/index.html (Retrived 20 March 2008)

Termite Behavior and Biology: http://www.allstatepestcontrol.com/user/Termite%20Behavior.htm (Retrived 20 March 2008)

The Coming Energy Crisis?: http://www.wtrg.com/EnergyCrisis/index.html (Retrived 20 March 2008)

Termites - Life's Ultimate Architects: http://www.youtube.com/watch?v=0m7odGafpQU&feature=related (Retrived 20 March 2008)

-Nigel Chong-

-Group 36-

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Format: ???
Duration: 6 minutes

Squirrels outsmart Snakes!

Reema Bhagwan Jagtiani — Mon, 17 Mar 2008 16:25:00 GMT

In a battle between predator and prey, it's refreshing to have the underdog emerge victorious from time to time, isn't it?

California ground squirrels (Spermophilus beecheyi) and rattlesnakes have been living side by side in apparent 'harmony' for years and just recently, studies have revealed just how these furry creatures have managed to keep their more 'sinister' predators at bay.

The technique? These squirrels threaten their predators by heating up their tails and shaking them vigorously. That's all it takes for the rattlesnakes, which in turn detect the infrared produced by the squirrels' actions, to slither off. Of course it helps that the adult squirrels are immune to rattlesnake venom so if one doesn't heed a tail-wagged-warning, it then risks facing an aggressive attack by the squirrels (this could involve biting and stone-throwing). Check out this article for more information.

This next link provides a detailed account of an experiment done on the above mentioned behaviour. The experiment highlights not only the increase in heat from tail wagging, it also reveals rattlesnake responses (they are rightly afraid of the heat) and shows that the squirrels only wag their tails in the presence of rattlesnakes (Gopher snakes, for example, cannot detect infrared signals).

One hot squirrel

In another study, the squirrels were found to also smear on snake scent by "picking up pieces of shed snakeskin, chewing it and then licking their fur." The deception works when snakes passing through think they've hit another snake burrow as opposed to a squirrel burrow.

The California Ground Squirrel

The squirrels' clever tactics show how they

1. Have adapted to a whole range of defenses against their predators

2. Display inter-species communication (through tail wagging or flapping and infrared signals) with the snakes

One researcher aptly sums up why I find the squirrels so impressive:

"It's a nice example of the opportunism of animals. They're turning the tables on the snake."

Citations:

"Hot squirrels,” by Brad Kloza. ScienCentralNews, 17 Aug 2007.
"Squirrel has hot tail to tell snakes," by JR Minkel. Scientific American, 14 Aug 2007.
"Squirrels use snake skin to disguise themselves from predators," by Andy Fell. Mongabay.com, 20 Dec 2007.
"Ground squirrels heat tails to combat rattlers," by Benny Bleiman. Scienceblogs: Zooillogix, 21 Aug 2007.

Pictures:
http://migames.files.wordpress.com/2007/09/squirrel-with-machine-gun.jpg
http://scienceblogs.com/zooillogix/2007/08/ground_squirrels_heat_tails_to_1.php
http://www.britannica.com/eb/art/print?id=5765&articleTypeId=1

Squirrels-Sneaky??

CHANG LI HUA CLARISSA — Sat, 15 Mar 2008 11:47:00 GMT

Squirrels! Cute, cuddly, fast, are a few words which come to mind when one mentions 'squirrel'. What we hardly hear of is how wily and cunning they are. I came across an article about squirrels burying their food in the ground. Sounds normal so far right? But get this, there is about 20% chance [The Daily Mail online article] that what the squirrels are burying is nothing more than thin air!

The species in question is the Sciurus carolinensis, or the free living eastern grey squirrels. Squirrels hoard their food, as well as pilferage others, and according to Steele et al. [2007], they have to weigh the benefits-being able to store food for later consumption, and the costs-risk of being 'stolen' by others. The eastern grey squirrels have increased their benefits through deceptive behaviour.

These squirrels, carrying the nuts they have collected, turn their backs on whoever is watching as they bury their nuts (be they rival squirrels, birds, or humans), dig a hole, drop in the nuts, and carry on digging other holes, but not burying anything. Alternatively, they may dig a few holes before selecting one to drop the nut into. They then proceed to cover it up with leaves and grass. Or they would even bury it under a bush, or climb a tree and put it in a nest. Visual cues and the sense of sight is imperative in deceptive behaviour [Steele et. al.]. Squirrels, with their keen sense of sight, will take note of potential 'thieves' and turn their backs to them while burying nuts.

Sneaky huh? So now we can add that to the list of characteristics one thinks of when someone mentions the word 'squirrel'.

According to Sylvia Halkins, a professor of biology from Central Connecticut state university, this deceptive behaviour observed in squirrels is relatively rare in animals [The Seattle Times online article]. It just goes to show how intelligent these furry creatures are.

Linking this to our lectures, I believe this is a form of adaptive behaviour, which squirrels have fashioned "to confuse any rival squirrels, birds or humans who might be watching" [The Daily Mail online article]. To take it one step further, squirrels are so sensitive to their environments, and so flexible, that they adapt on-the-spot.

Dr Michael Steele, of Wilkes University in Pennsylvania, together with a group of his students, conducted an experiment to test this deceptive behaviour of squirrels. The group watched squirrels as they buried their cache of nuts, and later, dug up these holes one by one. They did this a few times, and discovered that the percentage of bogus holes increased as their raids increased in number! [The Daily Mail online article] However, the increase was not very drastic [Steele et. al]

Even with their keen sense of smell, squirrels are unable to tell whether a covered up hole has a nut buried in it or not [Discovery Channel online news article]. Ironically, though squirrels perform such deceptive behaviour, they seem unable to believe other squirrels do it too. A squirrel watching another squirrel "bury" a nut, and goes to dig it up, will give up a search if it does not find a nut [Discovery Channel online news article].

So next time you see a squirrel, and luckier still, are able to watch it foraging and hiding its cache of food, do remember how sneaky and wily they can be!

Website references:

"Cunning squirrels make bogus burials of 'and seeds' to fool onlookers" by David Derbyshire, The Daily Mail, 16 January 2008

"Squirrels Fake Out would-be Nut Thieves" by Jennifer Vegas, Discovery News, no date. http://dsc.discovery.com/news/2008/02/21/squirrel-deception-02.html

"Squirrel behaviour is not so nutty" by Steve Grant, The Seattle Times, 22 November, 2004

Steele, M.A et. al., 2007, Cache Protection strategies of a scatter-hoarding rodents:do tree squirrels engage in behavioural deception?, Science Direct, 75: 705-714