How do they reproduce?
The grey nurse shark uses oophagy and intra-uterine cannibalism to reproduce. This results in a maximum of two young per litter. Embryos hatch into the uterus at about 5.5 cm long. At lengths of around 10 cm they develop teeth and consume other embryos in the uterus. The single remaining embryo in each uterus (there are two) then feeds on unfertilised eggs as the female continues to produce them. The shark pups measure about 1 metre long at birth. Gestation is between 9–12 months and females only reproduce once every two years.
The timing of mating and pupping in Australian waters is unknown, but it appears that these sharks give birth at select pupping grounds. Many sharks with bite marks gained during mating, have been observed at Pimpernel Rock, New South Wales, during the months of March and April.
The age at maturity might be around 9–10 years. The average life span of a grey nurse is unknown although it is probably more than 16 years.