Males outnumber females by a 2:1 ratio and multiple males will copulate with a single female. A dominance hierarchy has only been observed in captivity, with the oldest males copulating first.
Mating System: polygynandrous (promiscuous)
Mating occurs in November and October. The gestation period will take anywhere from six to nine months. Females give birth in early spring near coastal, rocky reefs. Caves inhabited by these sharks are also used as breeding grounds and, if disrupted, their breeding may be interrupted. Female sharks bear young once every two years, with a maximum of two shark pups at birth, one from each uterus. Grey nurse sharks are ovoviviparous which means that eggs develop inside of the female in each uterus. Young hatch from the eggs and are retained in the uteri until they are fully developed. Females have hundreds of eggs inside the uterus. When an egg is fertilized the shark pup begins to grow and, at 55 mm, develops a jaw and teeth. This shark then eats the other developing embryos during its 6 to 9 month gestation (intra-uterine cannibalism).
Males mature at a length of 1.95 meters, or 4-5 years in age, and females mature at 2.2 meters, or 6 years in age.
Breeding interval: Grey nurse sharks bear young once every two years.
Breeding season: Shark pups are usually born in early spring (March and April).
Range number of offspring: 1 to 2.
Average number of offspring: 1.
Range gestation period: 6 to 9 months.
Range age at sexual or reproductive maturity (female): 5 to 13 years.
Average age at sexual or reproductive maturity (female): 7-8 years.
Range age at sexual or reproductive maturity (male): 5 to 13 years.
Average age at sexual or reproductive maturity (male): 7-8 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); ovoviviparous
A pup will be born approximately 115-150 cm in length. This shark is able to fend for itself and live without parental care. Intra-uterine cannibalism ensures plenty of energy to the developing pup, resulting in a well-fed and well-developed offspring.
Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
- Carrier, J., J. Musick, M. Helithaus. 2004. Biology of Sharks and Their Relatives. Boca Raton, London, New York, Washington, D.C.: CRC Press.
- Cooper, P. 2006. "Sandtiger shark" (On-line). Ichthyology at the Florida Museum of Natural History: Biological Profiles. Accessed April 18, 2006 at http://www.flmnh.ufl.edu/fish/Gallery/Descript/Sandtiger/Sandtiger.html.
- Hamlett, W. 1999. Sharks, Skates, and Rays. Baltimore, Maryland: John Hopkins Press.
- Office of Naval Research. Sensory Biology of Sharks, Skates, and Rays. N00014-76-C-0943. Arlington, Va: U.S. Government. 1979.