Life History / Reproduction!
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Text Box: The Great White Shark and all elasmobranchs reproduce via internal fertilization. This is when the female sharks ingest the unfertilized eggs (oophagy) and hold them until they are fully developed. Elasmobranchs benefit from internal fertilization because this protects the eggs from being eaten by other organisms. Also, ingesting the eggs increases the efficiency of fertilization and decreases the amount of sperm wasted. Elasmobranchs can give birth via egg laying (oviparous), or live-bearing (viviparous). Specifically, Great Whites are viviparous, which means that they hold the embryos inside until they are completely developed, and born as moderately large, active sharks (CRC Press, 2004). While the embryos are still in the female shark’s uterus, white sharks are known to swallow sets of their own teeth that they have shed. They do this to re-use the calcium and other minerals that reside in the shark’s teeth (Martins, 2008).

Photo by Linda Reese
Text Box: The time that the female Great White holds the embryos has not been confirmed, but it is believed to be about a year. Birth of the embryos is believed to occur during the spring to late summer in temperate shelf waters. The female also gives birth in shallow waters so the risk of potential predators is greatly decreased. Once all the embryos are born, the litter size of the Great White Shark ranges from five to ten, and the baby sharks are usually between 120 and 150cm (47-59 in) long. Once the female has completed the birth process, it is believed that she will mate again very soon. Mating of Great Whites has unfortunately not been observed, so there is plenty of research to still do on the topic of reproduction (Green, 2005).

Photo by Linda Reese