The shortfin mako (Isurus oxyrinchus) is
believed to be the fastest-swimming of all sharks, thought to be
capable of attaining bursts of speed of up to 35 kilometres per hour,
and famed for making spectacular leaps of up to six metres out of the
water. The shortfin makos’ high tail produces maximum thrust to propel
the shark rapidly forward, both in extreme bursts of speed, and for
sustained, long-distance travel. The shortfin mako also has a heat
exchange circulatory system that enables the body to be warmer than
surrounding water, and thus maintain a high level of activity. This
large, stream-lined shark has a distinctively crescent-shaped caudal
fin, a long, conical snout, large black eyes and razor-sharp, blade-like
teeth. The upper body is a brilliant metallic blue, while the underside
is snow-white, with older, larger specimens tending to be darker with
reduced white areas. Juveniles are therefore generally paler than
adults, and also differ by possessing a clear black mark on the tip of
their snout. The shortfin mako can be distinguished from the only other
mako shark, the longfin mako (Isurus paucus), not only by having shorter
pectoral fins, but also by the white colouration on the underside of
the snout and around the mouth, which is darkly pigmented in the longfin
mako.