Sharks The Animal Answer Guide

28 Sharks: The Animal Answer Guide

Horn Sharks (Heterodontus—literally, “different teeth”) get their scien-

tific name from the different teeth in different parts of their jaws. Teeth

grade from sharp, cone-shaped teeth for grabbing and piercing at the front

margin to broad, rounded pads for crushing and grinding towards the back,

a good arrangement for impaling soft prey or picking up slippery snails and

clams and passing them to the back of the jaws for crushing. Bonnethead

Sharks, Sphyrna tiburo, small members of the hammerhead shark family

Sphyrnidae, also feed on hard-bodied prey and have pointy anterior teeth

for grasping and flatter posterior crushing teeth. Wolf-eels—bony fishes of

the northern Pacific and Atlantic oceans—feed on crabs, sea urchins, and

other hard-bodied prey and have a similar pointy-in-the-front, rounded-

in-the-back dental arrangement.

A few other oddities deserve mention. Selachian saw sharks (Pristio-

phoridae) and batoid sawfishes (Pristidae) are thought to feed in part by

slashing through schools of baitfish and then picking up the wounded.

Their functional “teeth” are on the outside edges of their elongate snouts

and are sharp, stout, smooth, and rounded, an effective tool for maiming

fish. Their jaw teeth are much less impressive, consisting of 10 to 12 rows

or bands of small rounded teeth with a slightly sharpened face on the back

edge. Being bitten by a sawfish would be much less traumatic than being

smacked by one.

Some of the biggest sharks have the smallest teeth, and in fact, teeth

may be basically nonfunctional (vestigial) in such megasharks as the Whale

Shark, the Basking Shark, and the Megamouth Shark. These sharks eat

Sharks and rays that feed on hard-bodied prey have rounded, flat, or pavement-like teeth good for crushing. (Left)
Upper and lower jaws of a Cownose Ray, Rhinoptera bonasus, a predator on clams, showing the flattened, pavement-
like dentition typical of many rays. (Right) Lower jaw of the Zebra Bullhead Shark, Heterodontus zebra. Heterodontid
sharks eat crabs, sea urchins, clams, and mussels. Their sharp anterior teeth seize items that are then passed back to
the stouter, rounder posterior teeth for crushing. Left, photo courtesy of Samantha Mulvany, used with permission; right, photo courtesy
of Phil Motta, used with permission

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