Squalidae is the family of dogfish shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

. They are found in the Atlantic, Pacific, and Indian oceans, from tropical equatorial climates to the Arctic and Antarctic.

Dogfishes are small to medium sized sharks, ranging from 48 centimetres (18.9 in) to 1.6 metres (5.2 ft) in adult body length. They have two dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

s, each with smooth spines, but have no anal fin. Their skin is generally rough to the touch. Unlike virtually all other shark species, dogfish possess venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...

, which coats its dorsal spines and is mildly toxic to humans.

These sharks are characterized by teeth in upper and lower jaws similar in size; caudal peduncle with lateral keels; upper precaudal pit usually present; and a caudal fin without subterminal notch.
They are carnivores and prey upon organisms smaller than themselves.

The livers and stomachs of the Squalidae contain the compound squalamine
Squalamine is a strong naturally derived broad-spectrum antibiotic that is predominantly derived from the livers of dogfish and other shark species...

, which possesses the property of reduction of small blood vessel growth in humans.
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