Foods and Feeding 153
strength of the bite is greater in durophages than in feeders on softer-
bodied prey. Horn Sharks and Spotted Ratfish have higher bite forces for
their body size than do fish- and squid-eating sharks such as Velvet Belly
Lantern Sharks and Spiny Dogfish. Cownose Rays generate bite forces 20
times greater than what is needed to crush the clams they eat. Such force
could damage the jaws if it weren’t for special adaptations in the jawbones.
The myliobatid Bat and Cownose rays have calcified struts in their jaw-
bones lined up with the crushing plates. These hardened struts keep their
jaws from twisting or collapsing when they are biting down on hard items.
Bull Sharks and White Sharks have the strongest bite force at any given
body size, probably because they feed on tough-bodied marine mammals
and turtles. Larger jaw muscles, increased leverage between upper and
lower jaws, dentition specialized for crushing, and mineralized jawbones
and struts—taken together, these features provide durophagous chondrich-
thyans with the feeding equipment necessary for handling prey defended
by toughness.
Do sharks store their food?
It is highly unlikely that sharks store food any place other than in their
stomachs. Water is a poor medium for food storage because it carries odors
so well. This makes it nearly impossible to hide a food item from scaven-
gers. It’s likely that there are other sharks around who, with their extremely
The sequence of head and jaw
movements that go into the bite of
a White Shark. (A) Normal resting
position; (B) snout is lifted and lower
jaw is dropped, achieving maximum
mouth opening; (C) lower jaw is
lifted forward and upward, and up-
per jaw is rotated forward and down-
ward, closing the jaws—the actions
that constitute the bite; (D) snout is
dropped back down and upper jaw is
pulled back to resting position. The
bite (component C) occurs quickly, in
about 0. 8 second. From T. C. Tricas and
J. E. McCosker, “Predatory behavior of the
White Shark (Carcharodon carcharias), with
notes on its biology,” Proceedings of the Cali-
fornia Academy of Sciences 43 ( 1984 ): 221 – 38 ;
used with permission