Most migratory sharks need to move to keep breathing, but the white-tip reef shark uses an ancient technique to rest during the day and save energy for hunting at night.

There are two main ways sharks go about breathing. Ancient shark species breathed through a method called buccal pumping, where muscles around the sharks’ mouths actively pull water in, sending it over their gill membranes and out the gill slits. The sharks absorb oxygen from the water as it passes by. Lots of sharks and rays that have adapted to bottom feeding use this method.

As sharks evolved to faster, stronger predators, many modern sharks have developed to breathe through a technique called ram ventilation. By swimming fast, these sharks actively force water into their mouths for processing.

Usually, sharks that get their oxygen through ram ventilation can also change techniques if they need to. But the largest and most successful predators in the open ocean have lost this ability entirely. The so called obligate ram ventilators — or obligate ram breathers — these sharks are the ones to have to swim constantly to stay alive. These include: the great white shark, the tiger shark, the bull shark, and the mako shark.

The white-tip reef shark belongs to the same family as these obligate ram breathers – the requiem sharks. It is the only species of requiem shark that is able to switch to buccal pumping to gain oxygen. This is used during the day, when this shark rests in a cave or under a coral ledge. That relaxation time pays off at night, when it hunts, chasing after its prey at great speeds.
But this species has not only adapted its breathing method to night-time hunting, their elongated body and posterior location of the first dorsal fin allow them to force their way into crevices and holes to extract hidden prey. Feeding primarily on bottom-dwelling octopus, lobsters, crabs and bony fish, it often chases its prey into a crevice before jamming its body in after it, sealing the exit. The white-tip reef shark usually hunts alone, but is non-territorial and will occasionally work in cooperation with others in the pursuit of prey.

« »