Page 334 - (DK) Ocean - The Definitive Visual Guide

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ORDER CARCHARHINIFORMES
Blue Shark

Prionace glauca
LENGTH
Up to 13 ft (4 m)
WEIGHT
Up to 450 lb (200 kg)
DEPTH
0–1,150 ft (0–350 m)
DISTRIBUTION Temperate and tropical waters
worldwide

A true ocean wanderer, the
blue shark makes seasonal
trans-ocean crossings in search
of food. It is streamlined and
elegant, with a long, pointed snout,
and characteristic white-rimmed
black eyes. On long journeys, it may
use its winglike pectoral fins to help it
glide on ocean currents. On the way,
it makes frequent, deep dives, possibly
to help it get its magnetic bearings.
When chasing fish, this shark may
reach speeds of 43 mph (70 km/h). It
has been known to harass swimmers
and has caused a few human fatalities.
Although one of the most common
sharks, it is also the most exploited
and its populations are declining.

ORDER CARCHARHINIFORMES species, the front of the head has three
notches, which produces the scalloped
Scalloped shape from which it takes its name.
The eyes are located at the sides of the
Hammerhead Shark head. Hunting near the seabed, the
shark swings its head from side to side,
looking for prey such as fish, other
Sphyrna lewini
LENGTH sharks, octopus, and crustaceans, and
Up to 14 ft (4.3 m)
using sensory pits on its head to detect
WEIGHT the electrical fields of buried prey
Up to 330 lb (150 kg)
such as rays. The head may also
DEPTH function as an airfoil, giving the shark
0–3,230 ft (0–1,000 m)
lift and helping it to twist and turn as
ORDER CARCHARHINIFORMES with serrated teeth that have the DISTRIBUTION Tropical and warm temperate waters it chases its prey.
worldwide
characteristic shape of a cockscomb. Scalloped hammerheads may be
Tiger Shark One reason it is so dangerous is that it seen in large shoals of over a hundred
prefers coastal waters and is also found Along with the seven other known individuals. They give birth to live
Galeocerdo cuvier in river estuaries and harbors, and so it species of hammerhead sharks, the young in shallow bays and estuaries,
LENGTH frequently comes into contact with scalloped hammerhead has a strange, where the skin of the young darkens
Up to at least 18 ft (5.5 m) humans. It is reputed to eat almost flattened, T-shaped head. In this to give protection against sunlight.
WEIGHT anything—as well as eating smaller
Up to 1,750 lb (800 kg) sharks, including young tiger sharks,
DEPTH other fish, marine mammals, turtles,
0–459 ft (0–140 m) and birds, it is an inveterate scavenger,
DISTRIBUTION Tropical and warm temperate waters and a huge variety of garbage has
worldwide been found in tiger shark stomachs.
The young, born live after hatching
The tiger shark is the second most from eggs inside the mother,
dangerous shark to humans, after the begin life marked with blotches,
white shark (see p.331). It is huge and which become “tiger stripes” in
has a heavy head and a mouth filled juveniles and fade by adulthood.

One of the sharks most often
ORDER CARCHARHINIFORMES
seen by divers is the whitetip reef
Whitetip Reef Shark shark, which during the day may
be found around coral reefs resting
in caves and gullies, often in groups.
Triaenodon obesus 1 The tip of its first dorsal fin and the
OCEAN LIFE DISTRIBUTION Tropical waters of the Indian Ocean contrast to its grayish brown back.
LENGTH Up to 6 / 2 ft (2 m)
upper tip of its tail are white, in
WEIGHT Up to 37 lb
(18 kg)
At night, the whitetip comes out to
DEPTH Typically 25–130 ft
hunt reef fish, octopus, lobsters, and
(8–40 m), recorded at
crabs hidden among the coral. Packs
1,080 ft (330 m)
sometimes hunt together, sniffing out
the prey and bumping and banging
and Pacific
the coral to get at them.