Tongue Lures Fish

large snapping turtle with pointed shell stands in an aquarium display

Biological Strategy

Alligator snapping turtle

AskNature Team

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Capture, Absorb, or Filter Organisms

Many living systems must secure organisms for food. But just as one living system must capture its prey to survive, its prey must escape to survive. This results in capture and avoidance strategies that include trickery, speed, poisons, constructed traps, and more. For example, a carnivorous plant called the pitcher plant has leaves formed into a tube that collect water. Long, slippery hairs within the tube face downward. When insects enter the tube seeking nectar, they lose their footing and slide inside, unable to climb out and escape being eaten and digested by the plant.

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Reptiles

Class Reptilia (“creeping”): Lizards, crocodiles, turtles, snakes

Reptiles retain some of the key characteristics that first enabled vertebrates to live permanently on land. They have dry skin covered in scales made of keratin that help prevent water loss. (Amphibians still need to stick close to water to keep their skin moist.) Many reptiles reproduce by laying eggs that are watertight and have a yolk, so eggs can develop on land while staying moist and nourished. Reptiles are also ectotherms, meaning they don’t produce their own body heat. This means they burn through energy much more slowly than “warm blooded” creatures of the same size. It also means that they need to keep warm to keep active, which is why you might see them spending a seemingly inordinate amount of time simply basking in the sun.

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The tongue of an alligator snapping turtle aids fish capture via a worm-like lure.

“An alligator snapping turtle lies in wait for a passing fish, well camouflaged against the muddy river bed. Like all turtles and tortoises, it has no teeth, but its jaws are covered in a sharp-edged horny beak suitable for shearing flesh. On the floor of its mouth is a fleshy pink worm-like lure, which the turtle waggles to attract fish. Eager to seize the ‘worm’, a fish may swim right in the turtle’s gaping mouth.” (Foy and Oxford Scientific Films 1982:142)

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Last Updated August 18, 2016

References

Book

The grand design: Form and colour in animals

26/02/1983 | Sally Foy

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Reference

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