The Top Three Most Bizarre Animal Teeth

Not all teeth are simple dentin and enamel. The infinite variation of evolution has resulted in teeth being modified for all sorts of specialized purposes, from eating tools to complicated sensory and navigational aids. Check out our top three strangest teeth adaptations in the animal kingdom.

The "Prism Teeth" of the Ardvark (image)
The aardvark — a small, insectivorous creature found throughout Africa, is in possession of one of the strangest sets of masticatory teeth found in mammals. The aardvark is nocturnal, spending most of its time raiding ant and termite nests for food, using its sticky tongue to capture prey. Strangely, the aardvark has one other food — a single type of cucumber that grows underground.

To eat these foods, the aardvark possesses an usual tooth set composed of pure dentin — more than 1,000 columns of vertically-oriented dentin prisms form columnar teeth which grow continuously over the course of the animal's lifetime. The order name Tubulidentata in the creature's scientific classification refers to this unusual dentition.

The Sensory Sword of the Narwhal (image)
Once thought to be an aquatic variant of the mythical unicorn, the narwhal is a close relative to belugas and possesses a single canine tooth which projects outward. This tusk, formerly thought to be a weapon or mating display, is actually an incredibly sensory organ that informs the animal about its surroundings. The tusk is hollow, and innervated with millions of sensory nerves that relay information about the ocean environment to the animal's brain.

This new information has changed researchers' interpretations of many narwhal behaviors, including "tusking," where males rub their tusks together in groups. Rather than a dominance display, research indicates this behavior may in fact be communication. Information about water chemistry and the oceans the animal has been in could be shared through microchannels in the tusk.

The Toxic Harpoon of the Cone Snail (image)
Perhaps the most frightening and unusual teeth on this list belong to the cone snail, a large mollusk in the Conus genus. This predatory snail lacks a traditional radula — a ribbon of tissue studded with teeth used for scraping algae off of rocks. Instead, the cone snail's teeth take the form of a hypodermic harpoon it uses to spear and paralyze its prey through delivery of a neurotoxic peptide.

These harpoons are manufactured continuously from an organ called the radular sac, located behind the animal's proboscis. The harpoon-teeth are not permanently anchored to the snail's mouthparts. Instead, they are held by muscles in the proboscis, which extrude the structure as necessary, and jettison spent harpoons after the prey has been paralyzed. This unique adaption ensures the snail always has a fresh harpoon readied for any potential prey that might come along.

These animals demonstrate how versatile teeth can be, adapted from the most basic of eating structures to complex sensory, defensive and predatory applications as diverse as they are strange.

Sources:
Conus Californicus. Retrieved April 25, 2016, from http://www.asnailsodyssey.com/LEARNABOUT/WHELK/whelCali.php

Orycteropus afer (aardvark). Retrieved April 18, 2016, from http://animaldiversity.org/accounts/Orycteropus_afer/specimens/collections/contributors/anatomical_images/family_pages/tubulidentata/tubulidentata

The Biology and Ecology of Narwhals. Retrieved April 25, 2016, from http://oceanexplorer.noaa.gov/explorations/06arctic/background/biology/biology.