How Sharks Hunt for Food
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Transcript of How Sharks Hunt for Food
S
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.