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Sharks: Their Hunt for Food.

By: Jon El Kordi-Hubbard BIO 003 03L

Cafferey

Scientists’ Prior Belief

Used to be thought that the concentration of the smell entering the nostrils was compared by sharks and used as a navigation tool.

Overview of Hunting Habits

Sharks are “scent hunters” Use noses to seek out prey

Distinguish which nostril the smell enters first Then swim in that direction Eddy Chemotaxis

Sharks entire bodies function as a giant nose Able to pick up the “shape of the smell”

Odor Plumes

Boston University Odor Experiment

Scientists ran a stream of squid odor through a circulating H20 tank and noted the sharks ability to find the source.

1. With no eddies or plumes the shark almost always failed

2. Then they placed a brick behind the scent, thereby jumbling the flow of the scent, the shark fared much better.

Hunting Habits cont.

On the sides of the sharks nerve-packed stripes called lateral lines.

These lines can detect vibrations made by other organisms in H20.

Foraging Strategies

Sharks use timing to orient themselves in the right direction

“Timing is a better tool because scents can travel through water in random, chaotic, patterns” Jayne Gardiner.

Other Foraging Strategies

“Levy walks” are done by sharks Long wanders in specific locations (based off

instinct). Sharks use math to hunt

They do not move randomly

Sharks make free decisions…

“Organisms, when allowed to make free decisions, seem to end up obeying some kind of mathematical law.” Gandhimohan Viswanathan (University of Glascow)

(DVM) Diel Vertical Migration

Large movements by predatory fish (i.e. benthic shark) to highly concentrated areas of food

Instinctive decisions Evolutionary trait

Energy conservation (easier to hunt in large concentrated areas of prey rather than small).

Conclusions

Sharks hunt using scent Attack success is directly related to prey density Use full body nose to detect movements of prey Instinctive creatures that do not move randomly DVM v. Eddy Chemotaxis are both used by sharks

Work Cited

Bhanoo, Sindyan N. "In Hunt for Food, Sharks Have a Sense of Timing." The New York Times 14 June 2010: D3+. Print.

Heat, By Body. "Great White Sharks Hunt Like Serial Killers : Discovery News." Discovery Channel : Science, History, Space, Tech, Sharks, News. Web. 30 Nov. 2010. <http://dsc.discovery.com/news/2009/06/22/shark-attacks.html>.

Sims, David W., and Victoria J. Wearmouth. "Hunt Warm, Rest Cool: Bioenergetic Strategy Underlying Diel Vertical Migration of a Benthic Shark." Journal of Animal Ecology 75 (2006): 176-90. Ebsco Host. Web. 22 Nov. 2010.

Witze, Alexandra. "Sharks Use Math to Hunt Their Prey: Marine Predators Cruise the Seas Using Fractal Principles." Science News 3 July 2010. Print.