Given this shark's relative notoriety, particularly among anglers, surprisingly little is known of its biology (9). Reproductive knowledge of this solitary species is sparse, largely because pregnant females usually abort embryos upon capture, making study difficult (3). Reproduction is ovoviviparous, with embryos being nourished in the uterus by a yolk sac rather than placenta. Once the young have hatched, uterine cannibalism known as oophagy occurs, in which the growing young feed on unfertilised or less-developed eggs (3). Litters of between 4 and 25 live young are born in the late winter and early spring, after a 15 to 18 month gestation period. This is followed by an initial relatively fast growth rate (2) (5) (7). Females are believed to rest for 18 months after birth before conceiving again (7). Females appear to become sexually mature at around 17 to 19 years of age and males mature around 7 to 9 years. The maximum known age of a shortfin mako is 32 years (8). The shortfin mako primarily feeds on a wide variety of fishes, such as swordfish, tuna, mackerel, cod, sea bass, and even other sharks, including blue sharks (Prionace), grey sharks (Carcharhinus) and hammerheads (Sphyrna). However, squid, sea turtle heads, and a 'porpoise' (probably a pelagic dolphin) have also been found in the stomachs of these sharks (9).