Bull Shark
Appearance: Stocky to very heavy-bodied species. Very short and broadly rounded snout. Small, circular eyes. First dorsal fin large and broadly triangular to somewhat falcate. Origin of the first dorsal fin usually over or just behind the insertions of the pectoral fins. No interdorsal ridge.
Coloration: Pale to dark grey. Fin tips are dusky, but not strikingly marked. An inconspicuous white band on the flanks.
Distribution: Widespread along the continental coasts of all tropical and subtropical seas. Travels far up warm rivers (the Mississippi, the Alabama). Western Atlantic: Massachusetts to southern Brazil, Gulf of Mexico, Caribbean Sea, Bahamas.
Biology: Found close inshore in water less than 90 ft. deep and occasionally less than a meter deep, but ranging down to 450 ft. It is the only shark that penetrates far into fresh water and apparently is able to exist there, though bull sharks are not able to maintain an entire life cycle in fresh water. In marine habitats this species commonly occurs in hypo- and hypersaline lagoons and bays.
Feeding: Opportunistic feeder, with a very broad food spectrum. Favoured food includes bony fishes and elasmobranchs (rays and other sharks, sometimes even other bull sharks) but feeds on sea turtles, birds, and dolphins.
Size: Maximum about 11 ft. (females); males reach about 10 ft.
Reproduction: Viviparous, with a yolksac-placenta. Gestation period is between 10 and 11 months. 1 to 13 pups per litter. Size at birth between 1.8 and 2.5 ft. Pups show a very slow growth rate. Males mature between 5 and 7.5 ft., females mature between 6 and 7.5 ft. Expected life span at least about 15 years.
Similar species: None.
Danger to humans: Probably the most dangerous shark species of tropical and subtropical waters. Bull sharks are one of the three most dangerous species, beside the white shark and tiger shark.
