LSM1303 Animal Behaviour

I love animals. I love them most when they are furry and warm, with whiskers and cute paws and small legs. Who can resist a bunny rabbit hopping around your legs begging you for food? Or a kitty cat snuggling into your arms for a rest? They’re simply irresistible. To do a write up about these cute animals, I might as well be setting up a website like cuteoverload.com, with pictures of baby rabbits, puppies and puggles. So on the contrary, I have decided to do a write up on the most disgusting creature I came across. This creature is by far the most heinous and repulsive, in all aspects, from its physical appearance, to its feeding habits, reproduction and most of all its defence mechanism! I present to you, the Atlantic Hagfish, also known scientifically as Myxine Glutinosa

The hagfish looks like an eel. In fact, it is very often mistaken for an eel and scientists have even debated whether or not it belonged to the fish family or the lampreys. It is the only animal with a skull but no backbone. Picture it as an underwater snake, if you will, with barbels (whisker like organ) instead of fins and a single nostril. Its colour ranges from grey to pink or brown, depending on the species and is found at a depth of 4000 feet underwater, making it a deep sea creature. The Atlantic Hagfish, as its name might suggest, is found on both sides of the North Atlantic Ocean and can go as far up as Norway.

If its appearance is not enough to repulse you, it’s feeding habits might. Albeit relatively small (16 -32 inches), the hagfish possesses a very barbaric and monstrous way of feeding. The hagfish starts off by attaching itself to another healthy fish. Unlike the Remora, the Hagfish does not stay at the sides or underneath its host, feeding on its remains, but bores its way into the host fish. The hagfish then feed on the host fish’s flesh with its tongue, literally eating its host inside out. There are instances where deep-sea fishermen found thousands of hagfish (instead of flesh) inside their catch! Be careful the next time you’re eating a Cod.

Sex with the Hagfish can be confusing. This is because some are hermaphrodites. Yes, they have both male and female sexual organs. A study conducted by Scott I. Kavanagh et Al in 2004 revealed that the production of gonadotropin-releasing hormone is highly seasonal and differs in relation to its size class and stage of gonadal development: “In the medium and large class hagfish, there was an increase in GnRH concentrations during April and May that correlated with male and female gonadal maturity. Also in these size classes of female hagfish, there was a similar rise in GnRH in November and then again in January that preceded the highest incidence of large eggs.”

What is known is that the hagfish’s eggs attach together and the Hagfish will curl itself around the eggs but it is not known if they are taking care of the eggs.Sexual Reproduction in the Hagfish is rarely documented and further study is much needed to those who can withstand its slime and grime.

Yes, the most disgusting fact about the Hagfish? Aside from its confused sexual orientation, its beastly eating habits and its unsightly appearance, the Hagfish is known for its defence mechanism. The slime. When provoked, the Hagfish excretes a whitish substance that, when in contact with water, will develop into a thick, slimy substance that reminds you of your own mucus! A Study by S.Subramanian et Al., discovered that a major constituent of the hagfish extruded slime are trypsin-like proteases. They found that stress induced slime of the Hagfish contains “various innate immune parameters in comparison to its epidermal mucus”. The slime excreted from the hagfish not only protects it from its predators (thickness of the slime clogs predators’ gills), but also from other diseases and micro organisms that might cause infection! Interestingly, the hagfish escapes from its own slime by knotting itself up and pushing this knot through its body.

The video below shows a scientist and his research animal: the hagfish.

If the video doesn’t load, click here to view: Hagfish Slime

Look at how just a teeny bit of excretion did to a beaker of distilled water! Do not underestimate the power of slime.

References:

Scott I. Kavanagh, Mickie L. Powell, Stacia A. Sower, (2005) “Seasonal Changes of Gonadotropin-releasing Hormone in the Atlantic Hagfish Myxine Glutinosa” General and Comparative Endocrinology, Volume 140, Pages 136-143.

S. Subramanian, N.W. Ross, S.L. MacKinnon, (2008) “Comparison of the biochemical composition of normal epidermal mucus and extruded slime of Hagfish (Myxine Glutinosa)” Fish & Shellfish Immunology, Volume 28, Pages 625 – 632

http://www.seasky.org/deep-sea/atlantic-hagfish.html

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

It is widely known that the only way to get a sex change is to have a surgical operation, but for chickens, they change their sex naturally, saving the cost for an operation! However, the known occurences are extremely rare, happening only in 1 out of 10,000 cases. “Every once in a while you hear a story about a hen that changed into a rooster. Such stories are often meet with skepticism, but sex reversals do, in fact, occur, although not very frequently,” says a 2000 report published by the University of Florida’s Institute of Food and Agricultural Sciences.

In an egg-laying barns where no roosters are present, a common behaviour arising from the hens are one of them will start crowing like a rooster. Generally, the hens only have one functional ovary, the left one, hence, once it is damaged, testorone will soar and regeneration occurs in the right gonad hypertrophies, which then regenerates as an ovotestis which consists tissues of either the testes or ovary, or both. This change is known as a spontaneous sex reversal and is extremely rare, usually happening only in barns which have a lack of roosters. The sex reversal will also occur when a rooster dies off and there is no rooster or a drastically small number of roosters left in the barn.

It is interesting to note that the hen will develop the behavioural and physical characteristics of the rooster as well. It will stop laying eggs, grow new plumage, a wattle and comb and starts the crowing behaviour. The sexually altered rooster will also try to mate with their old female mates. Although there are reports of the ovotestes producing semen and is able to reproduce, most however, are unable to reproduce.

Chicken run: George (1st in the photo) with some of the females he used to look like. The bird has become bossy since he swapped sexes and became a male Source: Daily Mail Reporter (http://www.dailymail.co.uk/news/worldnews/article-1080049/Pictured-The-sex-swap-chicken-called-Georgina-turned-cockerel-named-George.html)

Although majority of the sexually altered roosters are unable to generate semen to reproduce, the occurrence of this phenomenon is most probably to ensure a sexual balance in the brood or perhaps to maintain the need for a ‘boss’ figure in a brood of hens. However, it is intriguing to note that there are reports of these ovotestes having the ability to reproduce and another possible reason for the sexual change is to ensure reproduction is possible with non or few roosters in the brood to ensure continuation of its species.

Freaky- The sexually altered rooster

  Source: Bristol Evening Post

 (http://i7.photobucket.com/albums/y286/helena_the_chicken_lady/eveningPostChickenSexChange.jpg)

References:

1. Jacob, J and F. Ben Mather, 2000. Sex Reversal in Chickens. Department of Animal Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, FACTSHEET PS-53.
2. “The Sex-Swap Chicken Called Georgina that Turned into a Cockerel Named George,” by Daily Mail Reporter. Daily Mail Online, 23 October 2008.
3. “Letters: Sex-Change Chicken,” by M. A. Crooks. New Scientist, 16 May 1992.
4. “Strutting Super-Rooster is a Real Gender Bender,” by Geoff Bennett. Europe Intelligence Wire, 18 April 2006.

Hyena at the Ngorongoro Crater in Tanzania. (Credit: iStockphoto/Sebastien Burel)

Unlike most mammals, the social organisation of the spotted hyena is a matriarchy. The leader of the pack is a dominant female. And this dominance is encouraged and even heightened, argues zoologist Kay Holekamp, by both biological and sociological reasons.

According to Holekamp, the “length of time it takes for the massive skulls and jaws of hyenas to mature in youngsters” and ”feeding competition typical of hyena clans” cause the females to develop dominant behaviour and compensate for their youngs’ inadequacies. It also does not help that the males, as like most mammals, do not contribute to the rearing of their offspring.

A mother spotted hyena and cub. (Credit: Courtesy of Kay Holekamp)

Developing aggression as a favoured trait is further encouraged by the findings that higher ranking hyena females pass certain hormones that make their cubs more aggressive and sexually vigorous. This enables them to survive and thrive compared to their peers.

Besides these biological traits, hyenas also inherit their social status. If you watch the 1992 Production by National Geographics Eternal Enemies: Lions and Hyenas, this social structure is clearly evident. The role of the matriarch in establishing the order, however, is even clearer when she dies (not surprisingly from an attack by a lion). A small portion was captured on youtube.

Eternal Enemies: Lions and Hyena

Paul Ehrlich, David Dobkin & Darryl Wheye, 1988. “Cooperative Breeding” in The Birder’s Handbook: A Field Guide to the Natural History of North American Birds Including All Species That Regularly Breed North of Mexico. Simon and Schuster, New York.

Photo by Flickr user Jim Earle

They discuss the larger context of several species beginning with the Florida scrub jay which was highlighted in the lecture; excerpt:

“Scrub jays in Florida represent a group of populations that probably were once in contact with the widespread western populations but are now totally isolated. Only in Florida are Scrub jays cooperative breeders, and there they reside in permanent, group-defended territories.

Although pairing and breeding can occur after one year spent as a helper, birds often spend several years as nonbreeding auxiliaries. Males may remain in this subsidiary role for up to six years; females generally disperse and pair after one or two years of helping. Helpers participate in all nonsexual activities except nest construction, egg laying, and incubation. Pairs with helpers are more successful — they fledge one and a half times more young than pairs without helpers.

All available habitat [oak scrub] is occupied, and populations appear to be stable from year to year, which means young birds are unlikely to find vacant space to set up territories of their own. In contrast, Western Scrub-Jays generally are not space-limited, and the probability of a young bird leaving home and finding a territory in which to breed is high.”

The essay is hosted on “Birds of Stanford” webpage. They provide an excellent summary of cooperative breeding including aspects from: Glen E. Woolfenden, John W. Fitzpatrick, 1984. The Florida Scrub Jay: Demography of a Cooperative-Breeding Bird. Princeton University Press, N. J., USA. 406pp. Look under “Essays” and click the link for “Alphabetical order” to find “Cooperative Breeding”.

Click to see the BBC Video with a breathless David Attenborough getting quite close to a Beachmaster!

“There are slightly more than a dozen Oriental Pied Hornbills (Anthracoceros albirostris) in Singapore’s offshore island of Pulau Ubin. There they breed regularly, nesting in cavities found high up along the trunks of old trees.”

See “Oriental Pied Hornbill – breeding,” by Wee Yeow Chin with Jonathan Cheah. Bird Ecology Study Group, 05 Feb 2007.

Related links:

• “Oriental Pied Hornbills partying at Pulau Ubin,” by Angie Ng & R Subaraj. Bird Ecology Study Group, 07 Feb 2008.
• “Artificial nesting cavities for hornbills,” by Wee Yeow Chin with Angie Ng and Pilai Poonswad. Bird Ecology Study Group, 20 Dec 2008.

Bednarz, J. C., 1988. Cooperative Hunting Harris’ Hawks (Parabuteo unicinctus). Science, 239(4847): 1525 – 1527.

Abstract – Coordinated hunting by several individuals directed toward the capture and sharing of one Large prey animal has been documented convincingly only for a few mammalian carnivores. In New Mexico, Harris’ hawks formed hunting parties of two to six individuals in the nonbreeding season. This behavior improved capture success and the average energy available per individual enabled hawks to dispatch prey larger than themselves. These patterns suggest that cooperation is important to understanding the evolution of complex social behavior in higher vertebrates and, specifically, that benefits derived from team hunting a key factor in the social living of Harris’ hawks.

“Hawks stoop with a group to increase hunting success – cooperative hunting techniques,” by Christopher Vaughan. Science News, 02 April 1988.

Tag team competition extends beyond the professional wrestling arena. Groups of Harris’ hawks in New Mexico use a variety of cooperative hunting techniques, including a “relay attack,” to capture rabbits and hares.

Cooperative hunting, in which many animals team up to capture and share one large prey, has long been observed in a small collection of mammalian species including lions, hyenas and wolves. But this is the first documented observation of such coordinated hunting behavior in birds, reports James Bednarz in the March 25 issue of SCIENCE. “There have been reports of pairs of falcons hunting together during mating season, but the pairs weren’t very cooperative or successful,” says Bednarz, who did the work while at the University of New Mexico in Albuquerque and is now a staff member of the Hawk Mountain Sanctuary Association in Kempton, Pa.

Harris’ hawks are large hawks that normally survive by eating quail and other small birds. The hawks eat much better if they can capture rabbits or hares, but it is very difficult for a single hawk to do so because the speedy rabbits outweigh the hawks by as much as 3 to 1. Bednarz found that groups of four to six hawks increased their chances of capturing rabbits by employing group hunting techniques to seek out, then tire and confuse their prey.

… Continue Reading »

Joubert, D., 2006. Hunting behaviour of lions (Panthera leo) on elephants (Loxodonta africana) in the Chobe National Park, Botswana. African Journal of Ecology, 44(2): 279–281.

Introduction – Megaherbivores like elephants and rhinos have been regarded as invulnerable to predation as adults (Owen-Smith, 1988; G. B. Schaller pers. comm.), although Guthrie (1990) suggests that lions hunted such large prey during the Pleistocene. Recently, there have been a number of observations of elephants killed by lions in northern Botswana, going as far back as 1985 (M. Slogrove pers. comm.). The hunting behaviour of lions on elephants, and the age and sex structure of the elephants killed, were observed at a waterhole in the Savute region of Chobe National Park. The first observed elephant kill was recorded in August 1991. Systematic records of elephants killed were made between 1993 and 1996.

Loveridge, A. J., J. E. Hunt, F. Murindagomo & D. W. Macdonald, 2006. Influence of drought on predation of elephant (Loxodonta africana) calves by lions (Panthera leo) in an African wooded savannah. Journal of Zoology, 270(3): 523-530.

Abstract – Data were collected on species killed by lions Panthera leo in Hwange National Park, Zimbabwe between 1998 and 2004. Lions killed predominantly large to medium-sized herbivores, concentrating on buffalo Syncerus caffer, elephant Loxodonta africana, giraffe Giraffa camelopardalis, wildebeest Connochaetes taurinus and zebra Equus burchelli. These species made up 83% of all lion kills found and 94% of the biomass of kills actually observed.

Elephant calves made up an unusually large proportion of lion prey during the study period (23% of kills recorded). All elephants killed were dependent juveniles. Elephant calves appear more vulnerable during the dry months of the year, particularly in years of below average rainfall. Elephant calves are usually well protected. However, high-density aggregations of elephants around limited water sources during the dry season may deplete local food resources, forcing elephant herds to travel large distances between water and forage. Under these circumstances, elephant calves may become lost or separated from family groups, accounting for their high incidence in lion diet.

See also “The killing fields,” by Damian Whitworth. The Times (UK), 04 Oct 2006.

Emlen, S. T. & P. H. Wrege, 2004. Size dimorphism, intrasexual competition and sexual selection in Wattled Jacana (Jacana jacana) a sex-role reversed shorebird in Panama. The Auk, Apr 2004.

Photo source: Wikipedia

Abstract – We studied sexual size dimorphism, intrasexual competition, and sexual selection in an individually marked population of Wattled Jacanas (Jacana jacana) in the Republic of Panama.

Males are the sole incubators of eggs (28-day incubation) and primary providers of chick care (50-60 days). Females were 48% heavier than, and behaviorally dominant over, males. Females also showed greater development of secondary sexual characters (fleshy facial ornamentation and wing spurs) than males.

Both sexes defended territories throughout the year against same-sex conspecifics. Competition for territorial space was intense, and many individuals of both sexes did not become breeders. Resident females further competed with one another to accumulate multiple mates, resulting in a mating system of simultaneous polyandry.

Female and male residents (territory holders) were larger, heavier, and more ornamented than adult floaters of the same sex. Larger and heavier females also had more mates than smaller females. Body size was thus a critical predictor of success in intrasexual competition for territories (both sexes) and for mates (females).

…click to read more.

See also:

• “A male’s work is never done,” by Les Line. International Wildlife, Jul-Aug, 2000.
• “Jacanas and Polyandry,” (video and background). PBS: Evolution Library.

“Mobbing of Spotted Wood Owl at Toa Payoh,” contributed by Gloria Seow. Bird Ecology Study Group, 27 Jan 2008.