A big, plain, streamlined shark reaching over 4 m (13 ft) and 350 kg (770 lb), gray-bronze above with faintly dusky fin tips, a short rounded snout and long sickle pectoral fins. There is no single field mark: it is identified by proportion, and by the ridge of skin between its dorsal fins.
It is one of the slowest-living sharks in the sea. Females mature at about twenty years old, carry their pups for 22 to 24 months - a gestation matched among vertebrates only by elephants and a few deep-water sharks - and then rest a full year before breeding again. That is a three-year cycle producing perhaps ten pups, from an animal that has to survive two decades to start.
Do the arithmetic and the conservation story writes itself. A population fished at even a modest rate cannot replace itself, and recovery, once collapsed, takes generations rather than years: stocks in the western Atlantic protected since the 1990s are still measured in fractions of their former size. The species is Endangered.
Adults range from the coast out over the shelf and down to 400 m (1,300 ft), migrating with temperature, eating almost anything, including other sharks. Encounters with divers are uncommon and usually well offshore.
- short rounded snout and long sickle-shaped pectoral fins
- ridge of skin between the dorsal fins
- faintly dusky fin tips, otherwise plain
- large and heavy-bodied, over 4 m
