Whale Shark
The
Whale Shark (Rhincodon typus), the sole living member
of its family, is the biggest shark and the biggest fish.
It is NOT a whale. It has a huge mouth which can be up to
4 feet (1.4 m) wide. Its mouth is at the very front of its
head (not on the underside of the head like in most sharks).
It has a wide, flat head, a rounded snout, small eyes, 5 very
large gill slits, 2 dorsal fins (on its back) and 2 pectoral
fins (on its sides). The spiracle (a vestigial first gill
slit used for breathing when the shark is resting on the sea
floor) is located just behind the shark's eye. Its tail has
a top fin much larger than the lower fin.
The whale shark is up to 46 feet (14 m), weighing up to 15
tons. The average size is 25 feet (7.6 m) long. Females are
larger than males (like most sharks).
It has been estimated that whale sharks may live up to 100
- 150 years.
The whale shark has distinctive light-yellow markings (random
stripes and dots) on its very thick dark gray skin. Its skin
is up to 4 inches (10 cm) thick. There are three prominent
ridges running along each side of the shark's body.
This enormous shark is a filter feeder and sieves enormous
amounts of plankton to eat through its gills as it swims.
It was well-developed internal spongy filters at the gill
arches, which help to retain small prey within its huge mouth.
This mechanism may impede the flow of water through the mouth
during swimming, which limits the amount of plankton the shark
can strain. So, as well as filter feeding, it can also pump
water into its mouth to feed on concentrated patches of plankton.
Whale sharks are found worldwide in the warm oceans from
the equator to about ±30-40° latitude in all tropical
and subtropical oceans, along coastal regions, and enters
lagoons on tropical islands.. They are not, however, found
in the Mediterranean Sea. It is mostly seen on the surface
were divers and snorkelers can swim with this gentle, curious
creature.
The whale shark ranges throughout the western and eastern
Atlantic Ocean, the Indo-West, central, and eastern Pacific
Ocean.
|