146 Sharks: The Animal Answer Guide
tles, dugongs, sea snakes, other sharks, and bony fishes. Despite their repu-
tation for ferocity, they seldom chase after prey, preferring instead to sneak
up on it. As described earlier in this chapter (“What do sharks eat?”), if the
prey detects the approaching shark, the shark veers off. The Tiger Shark’s
overall foraging strategy is largely one of stalk and surprise. Spear fisher-
men in Hawaii say that you don’t have to worry about a Tiger Shark that
you’ve seen; it’s the ones you don’t see that are likely to attack. We’re not
sure that’s comforting.
Classic ambush predators, those that lie concealed on the bottom and
explode upwards to snag prey, exist among both rays and sharks. For ex-
ample, a South African butterfly ray species, the Diamond Ray (Gymnura
natalensis), lies on sandy bottoms, where its light coloration helps camou-
flage it. When a spawning squid approaches closely, the ray lunges out and
engulfs it.
The best-known ambushers among sharks are the squatinid angel
sharks, a crossover group that is a shark with the body of a skate. (The
giveaway clue is that angel sharks have gill openings on the sides of their
body rather than underneath, and the pectoral fins are not attached to the
head as in batoids.) Angel sharks typically find an ambush site near a reef,
lightly cover themselves with sand, and wait. If a prey fish or a squid swims
by close enough (no farther than 15 cm, or 6 in), the angel shark erupts
from the bottom at an upward angle, rapidly opening its mouth, which
creates tremendous suction pressure. At the same time, it protrudes its
jaws, thereby inhaling and impaling its prey, facilitated by extremely sharp,
pointed conical teeth and strong jaws. An entire strike sequence takes less
than one-tenth of a second.
The electricity-generating torpedo rays are good examples of sharks
whose hunting behavior varies with circumstance. During daylight, tor-
pedo rays lie in wait in the sand in the fashion of an angel shark. When prey
wander nearby, the ray leaps up and over the prey, cups its pectoral fins
(where the electric organs are located) around the prey, discharges its elec-
tricity, and then swallows the disabled victim headfirst. Output from the
electric organs can reach 45 volts and one kilowatt at a rate of 150 to 200
pulses per second. But at night torpedoes swim or drift slowly through the
water in search of prey that rest just above the bottom. When a prey fish
is encountered, the ray approaches to within 5 cm (2 in), lunges forward,
and wraps its pectoral fins around the fish. It then discharges its electric
organ, stunning the prey, sometimes breaking the prey’s spinal column by
the force of the electric shock. The immobilized prey is then grasped in the
mouth or forced to the bottom and consumed.
One other type of ambush predator is known, or at least hypothesized,
among sharks. These are the frequently mentioned 50-cm (20-in) dalatiid
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