Distribution:
Atlantic , Indian, and Pacific
Habitat:
Marine. Temperate to tropical, continental and insular shelves and slopes.
Remarks:
Most cow sharks are deepwater inhabitants of the continental and insular shelves and slopes down to 1875 m depth. They are found all over the world in temperate to tropical seas. Six gill openings are present in Hexanchus and seven in Heptranchias and Nortorynchus. The margin of first gill is discontinuous across the throat; teeth in upper jaw are distinctive from the comb-shaped teeth in lower jaw; one dorsal fin present. Cow sharks possess a strong subterminal notch-shape caudal fin and are ovoviviparous, lacking a yolk-sac placenta.
It can reach to maximum length at 4.8 m, although all species in this family range in size from 1.4 to 4.8 m.
The family consists of three genera and four species.
References: Compagno 1984; Nelson 2006