104 Sharks: The Animal Answer Guide
documented large trevally singly or in pairs repeatedly head-butting reef
species such as Blacktip Sharks and even Tiger Sharks. The trevally fo-
cus their ramming attacks on the sides and gill region of the shark. The
shark often defends itself by trying—unsuccessfully—to bite its more agile
attacker. Sometimes, a shark will attempt to flee to deeper water but be
forced back into the shallows by the attacking trevally. The trevally ignore
their own injuries, such as multiple cuts on their heads where they contact
the sharks, and keep ramming. After repeated high-speed rammings, the
shark, bleeding from its gills, sinks to the bottom and dies. Dissections
of victimized sharks indicate damage to several internal organs that were
probably the result of the rammings. Interestingly, trevally may ram more
than just sharks. A Hawaiian spear fisherman was rammed by a large Giant
Trevally, suffering three broken ribs.
How do sharks avoid predators?
Sharks avoid or deter predators in four major ways: (1) by running
away; (2) by hiding, either in a hole or in plain view but with camouflage
coloration; (3) by defending themselves with teeth, spines, toxins, or other
structures and chemicals; or (4) by being hard to chew or swallow. Chon-
drichthyan fishes do all four.
By Running Away. Running away can mean just trying to outswim
your predator, or it can mean moving to a safer locale. It all depends on
whether you are faster or more maneuverable than your pursuer. Juvenile
Lemon Sharks in the Bahamas take advantage of an incoming tide to move
into shallow areas around mangroves that larger, faster Lemon Sharks—
one of their main predators—avoid. Young Largetooth Sawfishes spend
their early lives in similar habitat.
Knowing when to run away is obviously important because getting
a head start can make all the difference. Some stingrays improve their
chances of detecting a predator and fleeing by associating with other sting-
ray species that are better at keeping a watchful eye for predators. Cowtail
Stingrays (Pastinachus sephen) in western Australia rest during the day on
sandy bottoms. When doing so, they prefer to rest near another species
of dasyatid ray, the Reticulate Whipray, rather than with other Cowtail
Stingrays. Reticulate Whiprays have a quicker flight response than Cow-
tails when a predator or a boat with researchers approaches.
It’s not just small sharks that run away from predators. Killer whales
are known to attack and eat White Sharks. Researchers studying White
Sharks at the Farallon Islands off California noticed that their study ani-
mals became scarce after one shark was eaten by a killer whale. One tagged
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