Blogging about animal behaviour (2010)

LSM1303 Animal Behaviour student posts

My Spit Can Outdo My Bites…

Filed under: Uncategorized — u0800128 at 10:11 am on Wednesday, April 14, 2010

The spitting cobra, namely the one we are looking at is the Mozambique Spitting Cobra. Some interesting facts before we go off further about its unique behaviour which I wish to highlight, known as Naja mossambica, the spitting cobra is revered throughout the globe, despite its small size. It can spit up to 2-3 metres, and it can cause much damage, blinding one or causing severe tissue dislocation. It is a neurotoxin and is a handy ‘weapon’ God has designed for this animal.

Whilst I can assertively say that this is not a learnt behaviour, as they are born with venom glands which are designed different from the others of normal cobras, there are distinct behaviours how these Spitting Snakes turn to their biological build to react to the surroundings and happenings around them.

The spitting cobra is usually more ‘angsty’ and easily agitated than the normal reptiles. As we know, snakes are general docile creatures. They usually do not pick a fight unless they are provoked, intentionally or unintentionally. The spitting cobra is similar. However, my own research tells me that they are generally more fiesty than the rest. Having known that their venom is ‘catered’ and ‘designed’ to spit rather than ‘bite’, it is probably instinctive that they will strike earlier than the normal snakes when they get a chance to.

The spitting is generally a defensive mechanism. The spit can go up to 10 miles/hour, faster than any imminent predator can react from. Living in the open plains, the cobras have very little place to hide and shun from their enemies, namely birds of prey or even larger snakes. With extreme accuracy to the eyes of the predator, the small snake can fend itself from predators more powerful than itself.

It does not, however usually hunt with its spit. Whilst the spit can fight off the predators, the slick agile movements of the spitting cobra is still a priceless attribute when it comes to hunting down from food. The snake hunts as it would hunt like any other ‘common’ snake we see.

This snake, in my opinion, is a beauty. A small fellow fending for himself with a unique gift, often shocking predators.

References

http://videos.howstuffworks.com/animal-planet/28417-fooled-by-nature-spitting-cobra-video.htm

http://guymclaren.com/mozambique-spitting-cobra-wildlife-photography/

  • Wesley H. Dickinson
  • Herpetologica, Vol. 3, No. 1 (Nov. 21, 1945), pp. 28-30
  • Published by: Herpetologists’ League
  • Stable URL: http://www.jstor.org/stable/3890505

Beavers saving the environment

Filed under: Uncategorized — u0703724 at 11:40 pm on Tuesday, April 13, 2010  Tagged

The beaver Castor canadensis is the largest rodent in North America and constructs dams with the complexity of what a civil engineer studies for his degree. They are second only to humans in their ability to alter their landscapes and also equipped with pragmatic skills to repair and upkeep their homes. Besides having such a talent, they are found to be monogamous and mate during January and February. Furthermore, they communicate with posture and scent marking, and slap their tails to signify danger of predators.

In the wetlands in Canada, the presence of a beaver had a considerable effect on the amount of open water. The ability to manage water is extremely commendable, and they command an overwhelming influence on wetland creation and maintenance such that they can mitigate the effects of a drought. Climate change has recently stormed the world with its threat to wipe out the planet, and there have been efforts to increase its awareness held at the Copenhagen Summit 2009. It was suggested that beaver impoundments have high resistance to disturbance such as flooding, and that the beaver can mitigate the adverse effects of climate change. However, they are not impervious to long-term droughts, which compromises the survival of their colonies.

It just goes to show that the beavers value adds the environment by its aesthetically pleasing sight as well as in climate change. With such a behaviour to constantly build dams for their shelter and prevention against predators, it still has a good cause to it!

References
National Geographic. Beaver. http://animals.nationalgeographic.com/mammals/beaver/

Hinterland Who’s Who. Beaver. http://www.hww.ca/hww2.asp?cid=8&id=82

Glynnis A. Hood, Suzanne E. Bayley. Beaver (Castor canadensis) mitigate the effects of climate on the area of open water in boreal wetlands in western Canada

So i am one and another, in summer and in winter…

Filed under: Uncategorized — u0802364 at 3:50 pm on Friday, April 9, 2010  Tagged

I was looking through the National Geographic website for a glimmer of information on an interesting animal to write about for this assignment, when an adorable, classic picture of a white rabbit caught my eye:

Snowshoe Hare: Lepus Americanus. Photograph taken by Michael S. Quinton for the National Geographic Society

Snowshoe Hare: Lepus Americanus. Photograph taken by Michael S. Quinton for the National Geographic Society

Definitely a far cry from the image that popped in my mind of the White Rabbit in Tim Burton’s recent movie! :

poster

Rabbits have been such a well-liked creature to be embedded in stories within entertainment and popular culture (think Peter Rabbit, Roger Rabbit, Bugs Bunny...)

By the way, ‘rabbit’ would be the widely misused term many might have in labelling the animal you see above. These white mammals are actually ‘hares’ (yes there are differences!) – one might be compelled to use them interchangeably, but technically both do differ in terms of size, appearance of offspring, ear length etc…

So the furry little creature you see in the first picture is known as the Snowshoe Hare (scientific name: Lepus Americanus), because of the size and shape of its hind feet which helps them stay atop thick patches of snow (this species being found particularly in many parts of the North American continent – USA and Canada – along elevated lands and even shores of the Arctic Ocean, though they can be seen down south such as around New Mexico)

They are also known as the Varying Hare – why? One of the reasons is due to its ability to change its fur colour according to the season! Towards fall and in winter the Snowshoe Hare has a white coat of fur, whereas towards summer it gradually changes to brown as that of this hare below:

Snowshoe Hare / Lièvre d'Amérique. Uploaded to Flickr.com by Eric Bégin

Snowshoe Hare / Lièvre d'Amérique. Uploaded to Flickr.com by Eric Bégin

Though carried out a long while back, a study done by Grange (1932) (my second source for this blog post) emphasises this adaptive behaviour of the snowshoe hare ” in avoiding intruders” (coupled with their sensitive ears and quick active legs in escaping predation) (Grange 1932, 101).  The seasonal molts as in the shedding of white fur could be triggered by changes in amount of daylight or temperature that induces a hormonal reaction and cause changes in coat. This helps the Snowshoe hare camouflage within its environment from the many predators it has (lynx, coyotes, owls, hawks…). A couple of interesting tidbits, as according to Grange:

- the changes in fur are not correlated directly to immediate climatic conditions, but significantly to average climatic conditions (i.e. there are cases whereby even in absence of snow, the fur changes from brown to white)

- colour change is observed to be coming from growth of hair of new colour, with growth of new fur for winter being “longer, heavier and thicker” (Grange 1932, 115); this difference in fur strand structure counters the notion of a direct change of the colour of the hair itself (instead of replacement) – there is observance that though some hairs are say, uniformly white, most of the fur strands are banded in diffused colours from root to tip.

Practical, and fashionable at the same time,  no?

References:

British Columbia (2003) Wildlife and Nature – Snowshoe Hare. Accessed 9 April 2010 from http://www.britishcolumbia.com/WildLife/wildlife/landmammals/cw/cw_snowshoehare.html

Fraley, J. (2006) Montana Outdoor Portraits: Snowshoe Hare.  Accessed 9 April 2010 from http://fwp.mt.gov/mtoutdoors/HTML/articles/portraits/snowshoe.htm

Grange, W.B. (1932) The Pelages and Color changes of the Snowshoe Hare, Lepus Americanus Phaeonotus, Allen. Journal of Mammology, 13(2), pp. 99 – 116

Harris, T. (2010) How Animal Camouflage works.  Accessed 9 April 2010 from http://animals.howstuffworks.com/animal-facts/animal-camouflage2.htm

Keith, L.B. (2010) Hinterland’s Who’s Who – Mammal Fact Sheet: Snowshoe Hare.  Accessed 9 April 2010 from http://www.hww.ca/hww2.asp?id=103 [online]

The National Geographic  Society (2010) Snowshoe Hare: Lepus Americanus. Accessed 9 April 2010 from http://animals.nationalgeographic.com/animals/mammals/snowshoe-hare/

Wikipedia (2010) Snowshoe Hare. Accessed 9 April 2010 from http://en.wikipedia.org/wiki/Snowshoe_Hare

Pictures Used:

Alice in Wonderland 2010 poster Alice and the Rabbit. Uploaded on February 22 2010 by christopher_aquino at Flicker.com.  Accessed 9 April 2010 from http://www.flickr.com/photos/cmaotaku/4378727576/

Snowshoe Hare: Lepus Americanus. Photograph taken by Michael S. Quinton for the National Geographic Society. Accessed 9 April 2010 from http://animals.nationalgeographic.com/animals/mammals/snowshoe-hare/

Snowshoe Hare / Lièvre d’Amérique. Uploaded on April 19, 2008 by Eric Bégin at Flickr.com. Accessed 9 April 2010 from http://www.flickr.com/photos/ericbegin/2426073031/

…and no, that wasn’t a car alarm.

Filed under: Uncategorized — u0702353 at 12:53 pm on Friday, April 9, 2010

I was carefully trawling the depths of Youtube the other day, when I came across this lovely video of a lyrebird demonstrating its fantastic vocal repertoire.

Intrigued by the video, I went on to dig up some information on the lyrebird. There are two species of lyrebird, the Superb Lyrebird (Menura novaehollandiae) and the Albert’s Lyrebird (Menura alberti); the photo above is a picture of a male Superb Lyrebird putting on a mating display. The photographer notes that it performed a repertoire that included “ [the] Yellow-tailed Black-Cockatoo, Grey Butcherbird, Crimson Rosella, Grey Shrike-thrush, Eastern Whipbird, Pilotbird, [and] Gang-gang amongst others.”

As can be seen in the photo, when putting on a courtship display, the male lyrebird spreads its tail out and fans it over itself  before launching into a display of its vocal ability – according to some sources, this display may last as long as twenty minutes.

Intrigued by the idea of vocal mimicry, I went to scour the Internet for more information, and discovered an article entitled “Vocal mimicry in songbirds”, published in 2008, which suggests several reasons why birds might engage in vocal mimicry. Reasons suggested include deterrence of potential intruders or competitors; however, one of the suggested reasons pertaining to the lyrebird is that they use their mimicry for “maintaining contact in the dense rainforest in which they live” (Kelley, Coe, Madden and Healy, 2008).   However, the article also acknowledges that this reason is still highly open to debate and that there is insufficient data to officially prove this claim (and that there has not been enough information to support any one claim of the importance of vocal mimicry for the past twenty-six years, which is a fairly daunting period of time). Which, sadly, leaves me hanging, wondering if any more new information will be turned up.

Sources:

“Attenborough: the amazing lyrebird sings like a chainsaw,” by BBCEarth. BBC Earth Youtube channel (18 May 2009). URL: http://www.youtube.com/watch?v=mSB71jNq-yQ (accessed on 3 April 2010)

Coe, Rebecca L., Healy, Susan D., Kelley, Laura A., and Madden, Joah R., 2008. “Vocal mimicry of songbirds.” Animal Behaviour, 76(3): 521-528.

“Superb Lyrebird (Menura novaehollandiae),” by kookr. Flickr, August 29 2009. URL: http://www.flickr.com/photos/kookr/3866749339/ (accessed 4 April 2010.)

Filed under: Uncategorized — u0701839 at 12:14 pm on Friday, April 9, 2010

When i was young, i often questioned why dogs hump. As i grew older, the answer *ahem* became rather obvious. However, one fine day, approximately 3 years ago, I noticed that my dogs were humping each other. Yes, you’ve heard it right. However, the most amazing thing is, all 3 of them are girls! They certainly do not do it with mating in mind, so why did this behavior occur so frequently? That was a question that plagued me till i bothered to find some articles on their behavior.

Well, a little bit on my girls. The first Otto, is a mongrel who my family adopted from SPCA. She’s been with me for about 14 yrs now. Then there was Lucky the poodle, who unlike what his name suggests, wasn’t so and passed away about 2 years ago. The next dog we got was Akita the Siberian Husky, who we actually bought off someone. Apart from her tearing apart birds like kingfishers on a weekly basis, she’s actually much fun being around the house. And finally, Joy Joy, my golden retriever who i picked up from SPCA while i was working there approximately 3 years ago. Mind you, apart from the first 2, the rest were adopted without parental consent. LOL.

Anyway, that’s besides the point. I first observed them actually humping each other after Akita hit her first sexual maturity. Initially, I questioned; Was it some sort of sexual behavior? It was intriguing as this used to happen a lot during play time especially between Joy (the GR) and Akita (Husky). It actually disturbed me quite a lot and i actually questioned if my dogs were lesbians. This was heightened by the fact that they used to reject the advances of Lucky, the only male dog in the house.

Well, it  turns out, as usual, the internet has all the answers.

1. The first reason why they hump is due to, irritation or itching in the genital area. Its probably a response to the physical irritation they find in that area. (Kathy Diamond Davis) However, I have long since ruled this one out due to the fact the vet “inspecting” their areas, and the all clear was given.

2. Spaying. Spaying a female dog will sometimes result in an increase in testosterone influence, if they produce androgenic (testosterone-like) hormones at  higher levels than most females and then the suppressing effect of estrogen is removed due to spaying. (Mike Richards) Well, this is another possibility, but the only spayed dog in my family is Otto and we’ve never really encountered such behavior from her. Maybe because she’s so much smaller than both the husky and the GR.

3. Dominance. It has been explained that humping is also used as a method to express dominance over another dog. While Otto might have been the first around, Akita, being a playful husky, has somehow managed to express her dominance over the rest. Firstly, physically, she’s a pretty huge husky, approaching the size of an Alaskan Malamute. The fact that it is usually her doing the humping acts as evidence as well. Through this behavior, she has managed to claim the role of the Alpha Female in the family, despite the irritation and annoyance of Otto, who sees herself as queen right from the start.

So next time, when you see dogs humping, don’t automatically assume its for mating reasons! And though it might seem strange, it is actually relatively normal behavior unless it does get so prevalent that you have to consider an obsessive/compulsive or anxiety based cause. (Mike Richards)

References

Mike Richards, DMV “Behavior – Mounting and Humping” http://www.vetinfo.com/dhump.html accessed on 9 April 2010

Kathy Diamond Davis “Humping: Is it all about sex? – Veterinary Partner.com http://www.veterinarypartner.com/Content.plx?P=A&A=1498

Kathy Diamond Davis, Therapy Dogs: Training Your Dog to Reach Others, Dogwise Publishing, Direct Book Service Inc. p. 127-130

Photos

photos are the poster’s own.

Dogs and humans are of equal importance??

Filed under: Uncategorized — u0601701 at 11:59 am on Friday, April 9, 2010  Tagged ,

A Korean show “TV Animal Farm” showed a weary family because of the aggressiveness of their dog towards their 16-month-old daughter, Sienna. The 4-year-old half-breed dog, Tobby appears as if it had two personalities: a cheerful and gentle dog to everyone including strangers and kids; a fierce dog which always growls or barks at Sienna when she is around. Although Tobby responds to Sienna when she calls it, it will start growling as it approaches Sienna, and following her while growling. Luckily, Tobby have not bitten Sienna before. Tobby also showed a strong jealousy when Sienna is playing with her daddy, Jamie.

A companion-dog etiquette educator* visited Sienna’s family and figured the reason behind the misbehavior of Tobby. Tobby was threatening Sienna—growling because it perceived as it has a higher rank in the family than Sienna. The reason behind the confusion of this hierarchy order was because the owner of Tobby, Jamie greets Tobby first when he came back from work. From Jamie’s point of view, he was greeting Tobby first because it greeted him first, where Sienna greeted him after Tobby did. It seems that Tobby and Sienna is in the same rank in Jamie’s mind, and the thought has been creating the tension of the family. As Jamie greeted Sienna first when he came back home, and after few trials of operant conditioning to view Sienna as a pleasing person, Tobby showed less aggressiveness towards Sienna.

In Chinese philosophy, there is a great debate whether humans are kind or evil in nature. Despite of the nature, the environment an individual grew up shapes her personality and behavior. I believe the same applies to the animals. Nowadays, many of the people perceive their pets as companion of life. Somehow, the importance of pet and human has become equal, and this was the reason of misbehavior in Tobby. If Jamie thought that Sienna was more important, he would have greeted Sienna first despite of who greeted him first, won’t him? Studies by Unshelm (1997) highlights that  dog management of the owner has a clear impact on dogs bahavior. Thus, rearing an obedient and nice dog is a responsibility of the owners and not that the dogs should be born with pleasing traits. It is not wrong to love pets, but we have to be aware that as pets become more and more important in human world, the significance of human to care for each other in the community might become more and more  less important. This trend can be due to the chaotic society where humans find no hope and no one to trust, but I still think that although dogs can be close friend of humans, humans should and would gain more effective help from humans. Are dogs as important as humans? Though dogs can be loyal friends of humans, humans are of utmost importance in the whole ecology, because humans shape the world. And to be frank, dogs especially the pets are products of sophisticated technology and science. 

 *Companion-Dog Etiquette Educator: (In Korea) A profession usually attended by veterinarians to educate etiquette’s of dogs. This profession also helps the owners to understand their dogs.

** Companion-Dog:  The perception towards pet dogs have changed in Korea recently. Pet dogs were previously called 애완견 (愛玩犬), meaning a dog you love such that you want to play with it and stay together. But nowadays, there are called 반려견 (伴侶犬), meaning a dog like a close friend of life, a companion of life. This shows that the view of Korean society regarding dogs have changed: from thinking the dogs are toys and an object to please ownself, to thinking that dogs are very important in daily life and thus adding humane trait to it–communicate with it and view it as a close friend.  

References:

“TV Animal Farm-Tobby-SBS” by SBS. Tudou 04 April 2010. URL:http://so.tudou.com/isearch/%E5%8A%A8%E7%89%A9%E5%86%9C%E5%9C%BA%20100404/

A. Roll, J. Unshelm, 1997. Aggressive conflicts amongst dogs and factors
affecting them. Applied Animal Behaviour Science, 52: 229-242.

How do dogs count??

Filed under: Uncategorized — u0900920 at 11:58 am on Friday, April 9, 2010  Tagged

Many have brought forward their pet dogs to the media with claims that their dog can count. It often involved certain reactions to specific questions posed by strangers to the dogs – usually based on simple mathematics. Slowly, people started debunking these attention-churning acts, with evidence that the owner was actually giving secret actions or secret hidden commands in his phrasing of words for his dog to follow.

The video below shows that dogs can count (somehow or rather)! Even without secret coded signals from the owner. The video is taken from the Animal Planet channel variety show, Pet Star. The show allows pet owners to flaunt the skills of their pet. Here we see that the judge, Debra, could not seem to find any secret signals between the two.

This raises the question. HOW IN THE WORLD DO DOGS COUNT???

I started to wonder if the body language of pet owners actually made a difference in their pets’ reactions. And in this case, if Maggie’s owner’s body language actually made Maggie know how many times to tap her paw.

Many of my dog owner friends shared the same sentiments that their body language and tone affected the way their dogs reacted to them. For instance, when friend A greeted his dog, A.J. with a subtle whine about how the latter had destroyed his play ball, A.J.’s initial cheery disposition turned into that of nonchalance about his owner’s return.

Similarly, could Maggie have sensed the different reactions of her owner and observers when facing the questions, and hence knew how many times to tap her paw?

This leads us to the observations of German comparative biologist and psychologist, Oskar Pfungst, who is most well known for his observations and contributing to what is now called the Clever Hans effect.Finding out about the Clever Hans effect answered almost all my questions.

First, let me explain what the Clever Hans Effect is.

It was a study starting in 1907, led by Pfungst, to investigate how Clever Hans, a horse could solve arithmetic questions. It was then concluded that, the horse would be able to answer the question if

  1. His owner could get the answer formulated in his mind
  2. The person posing the question knew the answer and was also in his sight

Keeping in sight the owner and the audience who posed the question allowed the horse to observe their reactions  and in turn know when to stop tapping his hoof in accordance to their reactions. For instance, if the answer were 4, he would tap his hoof until there was a change in tenseness amongst the audience. The change in tenseness was only natural among the (gullible if I might add) audience as they would wait in bated breath for Clever Hans’ answer, and would release their excitement gradually as he got closer to the answer.

Back to Maggie. I suppose that the reactions and expressions of the audience, the people posing the judges and her owner played a role in helping her know whe to stop tapping her paw. Judging by the way the crowd would cheer immediately after she got the answer, I have come to think that her arithmetic skills are simply more than meets the eye, but in fact a good observation of the reactions around her.

Hence, can dogs really do math? I wouldn’t rule out that possibility, but this post aims to give the general audience another take into the issue, rather than blindly believing or insisting that the dog has been trained to react to certain signals. It is clear that dogs do respond different to the body language, or expressions of those around them.

Reference:

Heini K.P. Hediger, Issue with The Clever Hans Phenomenon: communication with Horses, Whales, Apes and people. Vol. 364, 16 December 2006, Annals of the New York Academy of Sciences,

http://www.dumbassguide.info/blog.php?bid=6

http://www.sciencedaily.com/releases/2009/08/090810025241.htm

http://en.wikipedia.org/wiki/Clever_Hans

http://youtube.com

Using Elephants as Earthquake Detectors?

Filed under: Uncategorized — Wei Kit at 11:58 am on Friday, April 9, 2010  Tagged

Ever imagined having an Asian elephant (Elephas maximus) as a rather sizable earthquake detector? Well, that might not be as far-fetched as it sounds.. or does it?

The article “Did Animals Sense Tsunami Was Coming?” published by the National Geographic News, highlighted that in the recent 2004 tsunami that swept across the Indian Ocean, an estimated 150,000 people were killed in a dozen countries. Miraculously, it was noted that in places like India’s Cuddalore coast, where thousands of people died – animals like buffaloes, goats and dogs were found unharmed! At the same time, three elephants were said to have run away from the Patanangala beach at the Yala National Park about an hour before the tsunami hit.

Did the animals - specifically the elephants – have a kind of “sixth sense” that forewarned them of a major disaster before it struck?

Unfortunately, this was found to be untrue. On the day of the tsunami, the movements of these elephants were being tracked using GPS satellite collars. The empirical data strongly indicate that “the movements of these free-ranging elephants are not consistent with flight behavior or other potentially aberrant behaviors attributable to extra-sensory perception or sixth sense, or even with an early response to seismic-borne detection of the earthquake and tsunami” (Wikramanayake, Fernando and Leimgruber, 2006). Another article also documented similiar results, further warning that “in the absence of any evidence of a response of the collared elephants, the anecdotal evidence must be treated with added caution” (Garstang, 2009).

As such, the idea of utilising the elephants, as well as other animals in general, to forewarn humans of imminent natural disasters remains mere wishful thinking – at least for now.

References:

i. “Did Animals Sense Tsunami Was Coming?” by Maryann Mott. National Geographic News, 4 January 2005. URL: http://news.nationalgeographic.com/news/2005/01/0104_050104_tsunami_animals.html (Accessed on 9 April 2010).

ii. Wikramanayake, E.;  Fernando, P. & Leimgruber, P., 2006. Behavioral Response of Satellite-collared Elephants to the Tsunami in Southern Sri Lanka. Biotropica,38(6):775-777.

iii. Garstang, M. 2009. Precursor Tsunami Signals Detected by Elephants. The Open Conservation Biology Journal, 3:1-3.

iv. “Photo by Elephant Country Web” by University of Wisconsin-La Crosse. URL: bioweb.uwlax.edu/bio203/s2007/shah_rach/(Accessed on 9 April 2010).

Homosexuality

Filed under: Uncategorized — u0907903 at 11:56 am on Friday, April 9, 2010  Tagged , , , , ,

That caught your attention, didn’t it?

I bought a book off Amazon years ago, not knowing entirely what it was about. It could have been partially attributed to the discovery of buying stuff over the Internet, but the title did beckon at me from my computer screen.

This is the book in question; “Biological Exuberance: Animal Homosexuality and Natural Diversity” by author Bruce Bagemihl. It touches on the topic of animal behaviour that continues to debated by many scientists. And while there is plenty of evidence, it is difficult to extrapolate this evidence because of the human tendency to anthropomorphise such behaviour. Author Bruce Bagemihl himself highlights it in his book in the introductory passages.

So what about animal homosexuality? There is no reproductive benefits for two conspecific males to be engaging in reproductive behaviour with each other, with the exception of Sea Hares (Aplysia species and related genera) that are mostly hermaphrodites. What is the purpose of animal homosexuality?

Most observed cases of animal homosexuality occurs in animal groups with some form of social structure. For example, when male lions (Panthera leo) come of age, they are chased away from the pride they grew up in and begin a nomadic lifestyles until they find their own pride. Male lions have been reported to form pair-bonds with other solitary male lions, displaying affectionate activity with each other like mutual grooming, rubbing of heads and, in some cases, sexual activity between two males occurs. The same thing can be said about female lions as well.

There is no reproductive benefit among homosexual pair-bonds, but eventually, when a nomadic male lion finally becomes a resident in a pride, they have extraordinarily high heterosexual copulations with females, and vice versa.

In 2004, two male chinstrap penguins (Pygoscelis antarcticus) at New York’s Central Park Zoo made news when they were observed to have exhibited pair-bonding behaviour with each other already for six years running. Wild birds have also been observed such activity, the most notable being swans. Black swans (Cygnus atratus) and mute swans (Cygnus olor) have know to form homosexual pair-bonds and still exercise nest-building and (in females) egg-laying behaviour (even though the eggs are infertile).

So what is the benefit of homosexuality in animals? It has been noted that homosexual pair-bonds occur most frequently in animals that are rely heavily on social interaction or in unnatural environments (for example, zoos). There may be some benefit for animals that pair-bond. Taking male nomadic lions that pair-bond as an example, nomadic lions that stick together often have a higher chance of survival compared to a nomadic lion roaming by itself. Some birds that pair-bond share duties, such as foraging for food or protecting the nest, behaviour that may normally often identified in normal heterosexual pair-bonds.

Ultimately, animal homosexuality should not be viewed as an abnormality but as an aspect of biodiversity that is just waiting to be uncovered. There are still many questions to be asked and new aspects of the diversity of the animal kingdom (and ultimately, ourselves) still left to be discovered. Until then, all we can do is to marvel at why some animals do the things they do.

References

  • Bagemihl, Bruce. Biological Exuberance. Stonewall Inn Editions, 2000. Print.
  • Meyer-Bahlburg, Heino F. L. “Sex hormones and male homosexuality in comparative perspective.” Archives of Sexual Behavior 6.4 (1977): 297-325. Web. 8 Apr 2010. <http://www.springerlink.com.libproxy1.nus.edu.sg/content/g4757213w9045228/>.
  • “Aplysiomorpha.” 2010. Web. <http://en.wikipedia.org/wiki/Aplysiomorpha>.
  • “Homosexual behavior in animals.” 2010. Web. <http://en.wikipedia.org/wiki/Homosexual_behavior_in_animals>.
  • Owen, James. “Homosexual Activity Among Animals Stirs Debate.” National Geographic News 23 July 2004: n. pag. Web. 8 Apr 2010. <http://news.nationalgeographic.com/news/2004/07/0722_040722_gayanimal.html>.
  • “Book Cover Page.” Web. 9 Apr 2010. <http://jacketupload.macmillanusa.com/jackets/high_res/jpgs/9780312253776.jpg>.
  • “Two Giraffes.” Web. 9 Apr 2010. <http://en.wikipedia.org/wiki/File:Two_Giraffes.PNG>.
  • “Black swans.” Web. 9 Apr 2010. <http://en.wikipedia.org/wiki/File:Black_Swans.jpg>.
  • “Two male mallards.” Web. 9 Apr 2010. <http://en.wikipedia.org/wiki/File:Males_Anas_platyrhynchos_2_.jpg>.

Parental Infanticide: Children for Breakfast?

Filed under: Uncategorized — u0702948 at 11:52 am on Friday, April 9, 2010  Tagged , , , ,

Eclectus parrots, Eclectus roratus, exhibit reverse sexual dichromatism which means that males and females differ in terms of colouration (see fig.1). In eclectus parrots, stark differences in colour of the beak and plumage are evident from as early as when they are nestlings. In fact it is interesting to note that till a few decades ago scientists believed that the two were different species altogether!

Male (left) and female (right) eclectus parrots perched on branch.

Fig 1: Male (left) and female (right) eclectus parrots perched on branch.

However, this reverse sexual dichromatism is not merely of aesthetic significance. The eclectus parrot is reknowned for being able to exercise extreme bias in sexual allocation. Hence, this is the reason why: “one eclectus in Chester Zoo produced 30 sons before the first daughter was produced” (Heinsohn et al., p. 1325). So what is the secret behind being able to maintain such a remarkable bias in sexual allocation?

Fig. 2: on day 3 this check is already clearly a male due to its yellow beak.

Heinsohn recognises the likelihood, yet until further study merely specualtion, of bias to occur at fertilization and probably, during ovulation (ibid., p. 1328). However, scientists also recognise that infanticide and cannibalism is likely because nestlings go missing and no remains are found. In addition, since eclectus parrots can be easily sexed after hatching, the parents job of sexing their children is made appraent at first sight. Therefore, eclectus parrots it is either ‘death or love at first sight’. Siblicide is common amongst birds when the youngest nestlings are pushed off the nest. However, parental infanticide is a less well known area of study which Heinsohn promises to look at in closer in detail in his studies to come.

Closer to home, more substantial evidence of parental infanticide and cannibalism can be found in the case of the Oriental Pied Hornbill, Anthracoceros albirostris, in Singapore (photgrpahic evidence is included). Afterall, one may have to conlcude that parental supervision may not always be the best thing for children!!!

References

R. Heinsohn, S. Legge & S. Barry, 1997. Extreme bias in sex allocation in Eclectus parrots. Proceedings of the Royal Society, Biological Sciences, 264: 1325-1329.

Ellegren H, Gustaffson L & Sheldon BC, 1996. Sex ratio adjustment in relation to paternal attractiveness in a wild bird population. Proceedings of National Academy of Science USA, 93(21):11723-11728.

Kevin J McGraw & Mary C Nogare, 2005. Distribution of unique red feather pigments in parrots. Biology Letters, 1, 38-43.

“Infanticide-cannibalismm in Oriental Pied Hornbill,” Prof Ng Soon Chye et al. Bird Ecology Study Group, 09 Apr. 2009. URL: http://besgroup.talfrynature,com/2009/04/09/infanticide-cannibalism-in- oriental-pied-hornbill/ (accessed: 9 Apr. 2010).

“Oriental Pied Hornbill: Parental infanticide,” Marc Cremades & Prof Ng Soon Chye. Bird Ecology Study Group, 07 Jun. 2007. URL: http://besgroup.talfrynature.com/2007/06/07/oriental-pied-hornbill-parental-infanticide/ (accessed: 9 Apr. 2010).

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