From the whale company: The thresher shark is characterized by its large upper caudal fin which may often be 50 percent of the total length of the shark. The second dorsal fin is much smaller than the first. The color of this shark varies from brown to black with metallic hues from above and irregular white markings on the underside.
It has a short snout and large eyes placed forward on the head.
The maximum size recorded for this species is 6.1 meters; however they generally are between 2 to 5 meters in length. It is a strong swimmer and can leap clear of the water.
The thresher shark eats schooling fish, such as herring, mackerel and cephalopods such as squid. The large caudal fin is used to slap the surface of the water forcing fish to form tighter schools; the tail can then be used as a whip to stun or kill the prey.