UNDER THE SEA

 Hello ladies and gents this is the Viking telling you that today we are talking about

WHALE SHARK

The whale shark (Rhincodon typus) is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of 18.8 m (62 ft). The whale shark holds many records for size in the animal kingdom, most notably being by far the largest living nonmammalian vertebrate. It is the sole member of the genus Rhincodon and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984 it was classified as Rhiniodon into Rhinodontidae.

The whale shark is found in open waters of the tropical oceans and is rarely found in water below 21 °C (70 °F). Studies looking at vertebral growth bands and the growth rates of free-swimming sharks have estimated whale shark lifespans at 80–130 years. Whale sharks have very large mouths and are filter feeders, which is a feeding mode that occurs in only two other sharks, the megamouth shark and the basking shark. They feed almost exclusively on plankton and small fishes, and pose no threat to humans.

The species was distinguished in April 1828 after the harpooning of a 4.6 m (15 ft) specimen in Table Bay, South Africa. Andrew Smith, a military doctor associated with British troops stationed in Cape Town, described it the following year. The name "whale shark" refers to the fish's size, being as large as some species of whales, and also to its being a filter feeder like baleen whales.

Whale shark mouths can contain over 300 rows of tiny teeth and 20 filter pads which it uses to filter feed. Unlike many other sharks, whale sharks' mouths are located at the front of the head rather than on the underside of the head. A 12.1 m (39.7 ft) whale shark was reported to have a mouth 1.55 m (5.1 ft) across. The head is wide and flat with two small eyes at the front corners. The spiracles are located just behind the eyes. Whale sharks have five large pairs of gills. 

Their skin is dark grey with a white belly marked with pale grey or white spots and stripes which are unique to each individual. Its skin can be up to 15 cm thick and is very hard and rough to the touch. The whale shark has three prominent ridges along its sides, which start above and behind the head and end at the caudal peduncle. The shark has two dorsal fins set relatively far back on the body, a pair of pectoral fins, a pair of pelvic fins and a single medial anal fin. The tail has a larger upper lobe than the lower lobe (heterocercal).

Whale sharks were found to possess dermal denticles on the surface of their eyeballs which are structured differently from their body denticles. These denticles serve to protect the eye from damage, along with the whale shark's ability to retract its eye deep into its socket.

And as always have a chilled day from the Viking