The larger requiem sharks usually mature in six to 18 years, or longer, depending on the species. The maximum ages and years of reproductive life for these sharks can only be guessed. Current age research indicates that the largest individuals landed are 30 to 40 years old. Evidence suggests that certain dogfish species can live 70 years. Many of the large shark species reproduce every other year.
Many females are thin and emaciated when they reach full term.
Alternate year pupping may be required for the female to store sufficient nutrients to pass to the offspring. Some species such as the blue, hammerhead, sand tiger, and sharpnose sharks reproduce every year, as do most of the egglaying species. Male sharks are as reproductively complex as the females. Internal fertilization is accomplished using one or both claspers, which are rod-like appendages of the male's pelvic fins. Claspers are rotated and inserted into the female's vagina after a sometimes elaborate but poorly known courtship process in which the male bites the female's fins and flanks until she is receptive.