[This was written by Fran Siebrits and published online by Wild Magazine http://www.wildcard.co.za/, 2011]

According to a new study published in the Journal of Biomechanics, the jaws of adolescent great white sharks (Carcharodon carcharias) may be too weak to capture and kill large marine mammals.

Thanks to a unique jaw muscle arrangement, among other factors, sharks are among the most successful predators. An international team of scientists found that, unlike mammals, sharks can maintain high bite forces no matter how wide their jaws are open.

The study is the first of its kind to use sophisticated three dimensional computer models to show how different sharks hunt and kill their prey. These techniques where used to examine the bites of two different shark species. It revealed that the jaws of great whites are better suited for a powerful bite on different sized prey ranging from small fish to large marine mammals. This differed from the jaws of the grey nurse (or sand tiger) sharks, also tested in the study, which are spring-loaded for rapid bite action on small, fast-moving fish.

Even though the teeth and jaws of the adolescent great white shark look the part, the jaws themselves do not seem to be able to handle the stress associated with big bites on large sized prey. The muscles are there to drive a forceful bite, but are not yet operating at their full potential.

The study essentially shows that although young great whites have threatening teeth, they are unable to deliver a powerful bite. This paradox can be explained in their stage of development. The jaws of sub-adult great white sharks that have not yet reached about three metres do not have enough stiff mineralised cartilage. This lack of hard jaw-cartilage results in a weak force in the biting action.

The study also suggests that most great white attacks that are aborted after a single bite may be from juvenile great whites. One bite is all they can handle before jaw injury at that age and they are therefore not persistent in an attack on large prey. Even though a shark just under three metres would have most of us believe it has a jaw we would not like to encounter, they are actually rather vulnerable with awkward bites that cannot hunt large prey very effectively.

Great white sharks are not born as expert hunters. Like anything that needs to be perfected, they take years to become super-predators. The trick is being able to identify a three metre sub-adult from a powerfully practiced adult. I do not know of many creatures, human or non-human, who would hang around to find out though.

ScienceDaily, December 2, 2010