Sand Tiger Shark - Reproduction

Reproduction

Males reach sexual maturity at about six to seven years old and approximately 1.8 meters (6 ft) in length. Females reach maturity when approximately 2 meters (7 ft) long at about nine to ten years of age. Mating occurs around the months of March and April in the northern hemisphere. During mating, the male sand tiger grasps the female's fins with his teeth. This can leave deep cuts that normally heal within a week. The male shark uses claspers (modified pelvic fins), to inseminate the female. The sand tiger shark has one of the lowest reproduction rates of all species of sharks, therefore, they are easily affected by population pressures. Female sharks have two uteri. During early embryonic stages the young absorb nutrients from a yolk sac and possibly consume uterine fluids. At approximately 10 centimeters (4 in) in length, developing embryos in the mother's uteri are killed and devoured by two surviving pups, a process called intrauterine cannibalism (oophagy). There are reports of biologists probing the bellies of landed females and having their fingers nipped by the cannibalistic young with their fully developed teeth. The surviving embryos (one in each uterus) continue to feed on a steady supply of yolk capsules that contain 7-23 unfertilized ova. After a lengthy labour, the female gives birth to 1 meter (3 ft) long, fully independent offspring. The gestation period is approximately eight to nine months. Hydroids grow on the mother's teeth during pregnancy because she stops feeding.