LSM1303 Animal Behaviour Student Blog : defense mechanism

Inhuman Doctors: Zoopharmacognosy and Self Medicating Animals

Vigneshwaran Shunmugam — Fri, 21 Mar 2008 15:15:00 GMT

Many major cultures around the globe have developed some form of medical science. The Indians have Ayurveda, the Chinese have TCM and of course there is Western medicine. What these fields have in common is that they are derived from the process of observing the effects of certain herbs or foods on the health of the imbiber and thus correlating cause and effect. While medical science and its practitioners have long been held to be at the forefront of human intellectual pursuits, we now realise that this was no great achievement at all. In fact, even monkeys do it.

Observe this Orang Utan for example.

Right. This is just a monkey opening a packet of powder. Nothing fancy. However, monkeys DO develop their own medical techniques to deal with their own health issues. This is known as Zoopharmacognosy which is basically the animal form of Medical Science. Many species of animals use various techniques to deal with their maladies.

If you have seen your dog or cat eating grass you may have been puzzled at their sudden vegetarianism. They do have good reason for doing so. Eating grass "stimulates either retching or the rapid expulsion of worms in diarrhea" (Hart and Hart 1985). Compare this with the Tamil proverb which claims that a Tiger would not eat grass, no matter how hungry.

Medicine is not a purely mammalian pursuit either.Snakes too have herbological knowledge! "According to Chinese folklore, many centuries ago a farmer in the Yunnan district found a snake near his hut. Fearful for his life, he beat it senseless with a hoe and left it for dead. A few days later, the same snake returned. Again he tried to kill it, but again it returned. After he had beaten it a third time, the farmer followed the severely wounded snake as it crawled into a clump of weeds, started feeding on them, and thereby rapidly cured the worst of its injuries. The plant in the story was Panex notoginseng, which now forms the main ingredient in the herbal formulation 'Yunnan bai yao', a white powder that cauterizes cuts and stems external bleeding immediately. It was standard issue in the Vietnam War, for use when soldiers were wounded far from conventional medical treatment. "(Reid 1987).

Our closest cousins, the Great Apes have various methods by which they keep themselves in the pink of health.

Above we see a chimpanzee(Pan troglodytes) chewing on the bitter pith of the Vernonia Amygdalina plant. Chewing on the pith allows the chimp to extract the bitter juice that is within. THe chimpanzees use this method to kill parasites in their intestinal tracts. Interestingly, chimps do not usually eat this leaf due to it being slightly toxic to them. Thus, they only eat this leaf for medicinal purposes! This paper has extensive information on this phenomenon, complete with graphs. The author Michael Huffman is an eminent figure in the field of Zoopharmacognosy.

Chimps sometimes consume the leaves of the Aspilia plant, which they got to great lengths to obtain. The leaves are covered in stiff hairs and are swallowed whole, despite the difficulty of doing so. "Huffman doesn't doubt that there is a medicative function behind leaf swallowing behavior. His theory about how it gets rid of worms revolves around the hairiness of the leaves. Huffman found live worms in chimp *** stuck "like Velcro" to leaf hairs and trapped within the folds. He speculates that worms may become attached to the leaves or somehow enticed into the folds during digestion, taking a "magic carpet ride" through the gastrointestinal tract, eventually to be excreted from the body. Chemicals in the plant may also decrease the ability of the parasites to adhere to the intestine, making it easier for them to be swept out by the leaves."

Perhaps the animal use of medicines to treat themselves is not such a surprising phenomenon. In fact post-Darwinists should have predicted it regardless of evidence. Using medical methods enables an animal to prevent its death,prolong its life, to heal faster and have a survival advantage. This is an advantage that would allow those animals who use it to be more successful than those who dont. In the abscence of a consequent negative selection pressure, animals who self-medicate would definitely outsurvive those who do not. Thus, Zoopharmacognosy is not surprisingly prevalent in the animal kingdom.

Not only do animals consume herbs and plants as medicines, but they also consume certain types of soil(geophagy) and insects for the same purpose.

Even more interesting than the fact that animals employ medical science is the fact that many of the herbs and techniques employed by animals are similarly employed by humans. This highlights the cross pollination of medical knowledge from the animal kingdom to ours.

To learn more on the exciting field of Zoopharmacognosy, this book might help.

"Really Wild Remedies—Medicinal Plant Use by Animals" by Jennifer A. Biser. Zoogoer, January/February 1998

Huffman, M.A. 2001. Self-Medicative Behavior in the African Great Apes: An Evolutionary Perspective into the Origins of Human Traditional Medicine. Bioscience, 51(8):651-661.

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The Stinging Sailor

LIAU QINGYE EILEEN — Fri, 21 Mar 2008 06:10:00 GMT

Now, what could this be?

a) An inflatable float.

b) A breathing apparatus.

c) A Jellyfish.

Answer: d) None of the above.

What this inflatable jellyfish like animal is an invertebrate, the Man- of –war. It does have a rather impressive name, but IS IT impressive?

As I have found out from this article, it is indeed extraordinary.

The Man- of – war is not exactly ONE animal, but is actually a floating hydrozoan, which consists of four types of polyps. The four different simple animals that form the Man- of – war are the float, the tentacles, the feeding zooids and the gonozooids which produce gametes for reproduction.

Click here for more information on polyps.

These different polyps work together to form an intelligence system that functions as a whole. Each polyp has a different function, which helps in the survival of the Man- of – war. For example, the float polyp helps in the locomotion of the Man- of – war. It is like a sac filled with nitrogen, and acts as a “sail” to drift the animal in the direction of the wind and tide. This is also where the Man- of – war derived its name from, as it resembles an olden day battle ship.

With all these different animals living “under the same roof”, one must wonder why they do so and how they do not feel a competition for resources.

Each polyp has different needs and functions. Other than the “sail”, one other part is for reproduction, while the remaining two parts function as the hunting and digesting tool.

Man- of – wars are hermaphrodites; each individual gonozooid consists of male and female parts. The fertilised egg develops into a planktonic larva which then reproduce in large quantity by asexual budding.

The most powerful part of this combined animal is the tentacles, not only do they contain a painful sting which can be fatal, they are also used to catch and trap small sea creatures which will then be slowly dissolved by enzymes secreted from the underside of the float.

As you can see, these four simple animals coexist as “one organism” because the benefit of doing so greatly outweighs the cost involved. Although a single animal has a function by itself, it will never be able to survive alone, as it lacks other necessary functions for survival.

I find this animal really amazing because it has managed to survive even without doing much. There’s no need to swim as the “sail” helps in drifting. Eating for this animal is also like a simple task as it simply traps and dissolves its prey; absolutely no need for foraging or stalking. In addition, there is no need for MATE- SELECTION, a process which many other animals spend alot of time and energy engaging in.

At this point, we wonder what could possibly lead any fish to swim through the deadly tentacles of the Man-of –war.

The answer?

The Nomeus gronovii.

This fish shares a symbiotic life with the Man-of-war.

Want to see the Man- of- war in action?

Man-Of-War Podcast!

Remember to look out for the Man-of –war fish, as well as the enemies of the Man-of-war.

Here's some trivia:

As compared to a jellyfish, the man-of-war is a giant.

As compared to a grown man...

it STILL is a giant!!

See also:
Man Of War Fact-file
Team Transformation Rule 2: Cultivate Team Intelligence
What to do when you get stung by a Man-Of-War??

Reference:
Websites:
Kurlansky, Mindy B. (2002). Physalia physalis. Retrieved March 20, 2008, from Animal Diversity Web Web site: http://animaldiversity.ummz.umich.edu/site/accounts/information/Physalia_physalis.html

Polyp. (2008, March 17). In Wikipedia, The Free Encyclopedia. Retrieved March 21, 2008, from http://en.wikipedia.org/w/index.php?title=Polyp&oldid=198944134

Portuguese Man-of-war. In National Geographic. Retrieved March 20, 2008, from http://animals.nationalgeographic.com/animals/invertebrates/portuguese-man-of-war.html

Pictures:
Man-of-War Fish - Nomeus gronovii. In thejump.net. Retrieved March 20, 2008, from http://www.thejump.net/id/man-of-war-fish.htm

Portuguese Man-of-war. In aloha.com. Retrieved March 21, 2008, from www.aloha.com/~lifeguards/portugue.html

Nomeus gronovii- Man-of-war fish. In FishBase. Retrieved March 21, 2008, from http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=2461

Video:
Portuguese man-of-war. In National Geographic. Retrieved March 20, 2008, from http://podcastmedia.nationalgeographic.com/ngvideos/pc62_PortugueseManowar.mp4

I will slime you if you come near me!

Teo See Ching — Wed, 19 Mar 2008 14:02:00 GMT

Many weird, creepy creatures dwell the deep sea and the Hagfish is one of them. Looking nothing like a fish, it resembles an eel with an 'alias' "Slime eel". It belongs to the group of primitive, jawless fish which includes the marine and freshwater lampreys known as Myxini.

(http://www.ryanphotographic.com/myxinidae.htm)

So it just looks a teeny bit disgusting. What makes it truly fascinating is its defense mechanism. When captured and held by the tail, it escapes by secreting the fibrous slime, which turns into a thick and sticky gel when combined with water. The slime surrounds the predator and protects the hagfish. It can even kill the predator if it comes into contact with the slime which will clog its gills (but sometimes hagfish even kill themselves with their own slime haha) When the hagfish thinks it's safe, it ties itself in knots to get rid of the excess goo. The video below will show how this slime is produced by the hagfish when disturbed; the subsequent picture is that of the glands which secrete the slime.

(http://courses.washington.edu/chordate/453photos/skin_photos/special_integument1.htm)

Other than for individual defense and for frightening humans, the slime may be used to deter predators from hagfish nest eggs. More appalling, however, is its use as a replacement for egg whites in cooking, and oils in various ointments!

Aside from its sliming mechanism, what really makes the hagfish a deep sea monster is its eating habits. It feeds by attaching itself to a passing fish, boring its way inside its unsuspecting host. Once inside, the hagfish will actually eat the fish's flesh with a specialized rasping tongue, literally eating its victim from the inside out, thus leaving a jagged hole in the hapless victim!

Nonetheless, notwithstanding its repugnant, parasite-like appearance and sliming tactics, Jean Lee (an Undergraduate of Integrative Biology, University of California, Berkeley) has contended that the hagfish are actually “useful in the study of tumours [and] the cooperation of body parts in producing slime (essentially polypeptides) is also important in examining functionality, morphology, and metabolic actions”. On top of this, the Koreans have even made it part of their gourmet!

(http://www.msnbc.msn.com/id/19336602/)

Eel.

References

Jean Lee. Hagfish Aren’t So Horrible Afterall. (2002). Journal of Young Investigators, Volume 5, Issue 7. Retrieved 19 March from http://www.jyi.org/volumes/volume5/issue7/features/lee.html

DivaBoo. 25 World’s Weirdest Animals. Retrieved 19 March from http://divaboo.info/

Ocean Link. Hagfish. Retrieved 19 March from http://oceanlink.island.net/oinfo/hagfish/hagfish.html

Hey! That's My Clone!

LIM HWEE HOON — Tue, 18 Mar 2008 21:39:00 GMT

University of Washington biologists have recently found out that sand dollar larvae created clones of themselves when being exposed to fish mucous, a cue that predators are near. In each case, the cloning process resulted in a small new larva and the original larva substantially smaller than it had been. This decrease in size can effectively make them invisible to the predatory fish, thus prevent them being killed by the predators.

So have you heard of Sand Dollar? Please don’t be mistaken it as a dollar made of sand =D.

Sand dollars (Dendraster Excentricus) are from the class of marine animals known as Echinoids, spiny skinned creatures. They are 75 mm wide to 6 mm high, light gray, brown to dark purple; disk-shaped, flat upper and lower surfaces are covered by fine, spiny tube feet; central mouth on lower surface.

I believe many of you, like me, will be very curious and unsure of what a sand dollar is. Below are some of the pictures of both adult and baby sand dollar.

Baby sand dollar in the process of cloning.

Dendraster Excentricus

Sand dollars can also be found in Chek Jawa in Singapore. The common sand dollars are Cake sand dollar and Keyhole sand dollar.

Interesting Points to Highlight:

Studies have shown that the larvae of Echinoderms such as sea urchins and starfish clone themselves for the purpose of asexual reproduction. However, in this case, the baby sand dollars were found cloning themselves in face of danger, as a defense mechanism.
In nature, many animals do try to prevent being preyed on or scare their predators away by becoming bigger in size. Nevertheless, these baby sand dollars make themselves smaller so as to become invisible to the predators.

The baby sand dollars only clone themselves when they detect danger. The external stimuli that caused the defense mechanism in them is the chemical cues of the fish mucous emitted by the fish. Once they detect the potential threat from the predators, they will change in their shapes and clone into two. The question raised was whether these smaller larvae can survive through during their adulthood since they are obviously smaller than those which have never cloned before.

Websites:

http://www.wildsingapore.com/chekjawa/text/s620.htm

http://www.gma.org/Tidings/sanddollar.html

http://www.nwmarinelife.com/htmlswimmers/d_excentricus.html

References:

University of Washington (2008, March 14). Sand Dollar Larvae Use Cloning To 'Make Change,' Confound Predators. ScienceDaily. Retrieved March 19, 2008, from http://www.sciencedaily.com /releases/2008/03/080313143100.htm

University Of Alberta (2003, September 11). Young Sea Animals Clone Themselves—century-old Debate Halted. ScienceDaily. Retrieved March 19, 2008, from http://www.sciencedaily.com /releases/2003/09/030911072551.htm

SH*T on YOU!

CHENG WENZHANG — Sun, 16 Mar 2008 15:26:00 GMT

Do not be mistaken! This is NOT a blog attack! Instead, Fieldfares (Turdus pilaris) literally use faeces as a form of attack against predators. This form of “defensive defaecation” (Meilvang, Moksnes, Reskaft) is an effective weapon against predators, as shown in this video: Attenborough: Life of Birds: Fieldfares and Raven

A study on nest predation in Fieldfares was conducted and results showed that seventeen percent of the Fieldfares nests suffered predation and that this figure is significantly lower when Fieldfares live in colonies (Meilvang, Moksnes, Reskaft). Colonial-nesting in Fieldfares helps in early predator detection, allowing them enough time to assemble a defence force and drive the intruder away. Their actions are defensive rather than aggressive, as their aim is to distract and drive the predator away from the nest (Hogstad).

Fieldfares have a systematic way in carrying out their defence. They first raise an alarm call when a predator is detected, followed by diving and clawing at the predator and finally, defaecating on the predator. As in the case of the video, the young raven’s feathers risk getting waterlogged if it is continually defaecated upon by the Fieldfares. Once the feathers are waterlogged, the raven is unable to fly and risk being attacked by the Fieldfares. However, a point to note, the ejecting of faces on the predators by Fieldfares only works well with avian nest predators, and has little effect on mammalian predators as Hogstad has shown in his study.

Usually, animals defaecate to mark their territories rather than use it as a form of defence against predators, which is why I find the employment of such a technique in Fieldfares interesting and unique. I ran a search through the Internet and it seems like only Fieldfares eject faeces on predators. In addition, the cooperative hunting in Harris hawks (Parabuteo unicinctus) also roused my interest to blog about animals living in groups [Bednarz, J. C., 1988. Coopoerative Hunting Hawks (Parabuteo unicinctus). Science, 239(4847: 1525 - 1527.] .

Citations:
D. Meilvang, A. Moksnes and E. Reskaft. Copenhagen 1997. Nest predation, nesting characteristics and nest defence behaviour of Fieldfares and Redwings. Journal of Avian Biology 28: 331-337.

Hogstad, Olav. Nest Defence Strategies in the Fieldfare Turdus pilaris: The responses on an avian and a mammalian predator.

References:
Slagsvold, Tore. Egg predation in woodland in relation to the presence and density of breeding Fieldfares Turdus pilaris. Ornis scandinavica 11; 92-98 Copenhagen 1980.

http://www.birdsofbritain.co.uk/bird-guide/fieldfare.asp

http://www.birdguides.com/html/vidlib/species/Turdus_pilaris.htm

Image Source:
http://telbirding10.blogspot.com/2007/11/fieldfares.html