Bite Club

Saturday 2 April 2005

Researchers have discovered that the marsupial lion Thylacoleo carnifex, which roamed Australia during the ice age, had the strongest bite force for its size of any large carnivorous mammal.

In a paper published (online) in the Proceedings of the Royal Society Series, Mr Colin McHenry from the Faculty of Science and Information Technology, University of Newcastle, Dr Stephen Wroe, University of Sydney and Professor Jeffrey Thomason, University of Guelph, Ontario, investigated the bite force of living and extinct carnivores, from the Tasmanian Devil, lions and hyaenas to the sabre-toothed 'tiger' and marsupial lion, in order to establish the relationship between bite force and relative prey size.

Colin says bite force is an important aspect of carnivore ecology and can assist in understanding the evolution of community structure and prey size of extinct species.

"We compared skull mechanics and jaw muscle size in nearly 50 species," says Colin. "This allowed us to calculate and compare bite force in existing and extinct species in relation to body mass and head size."

"Among living species the Tasmanian devil takes the honours, easily outstripping the bone-cracking spotted hyaena on a weight adjusted scale."

"Maximum prey size is an important component of a predator's ecology, and since the jaws and teeth are the business end of a carnivore we hypothesised that maximum prey size is set by the biomechanical limits of its skull. We found that bite force predicts the maximum size of prey relative to the predator's own body size."

"This is very useful for palaeontologists who wish to reconstruct life-style in extinct carnivores. Results indicate that relative to body mass, the bite force of marsupial carnivores is considerably higher than in predators of the cat and dog families."

"In the case of the marsupial lion, its calculated bite force was equivalent to that of an African lion nearly three times its size. This suggests that Thylacoleo carnifex could take prey much larger than itself," says Colin.

Related to wombats and koalas, Thylacoleo carnifex is referred to as the Marsupial lion because of its robust, cat like appearance. It averaged around 100kg and was capable of grasping its prey with strong semi-opposable thumb claws.

Combined with its powerful jaws and large incisor teeth the Marsupial Lion was the largest mammalian predator in Australia during the Pleistocene period and became extinct sometime within the last 45,000 years.

The team are now working with the Newcastle Mater Hospital and mechanical engineers at the University of Newcastle to investigate the structural mechanics of the skull in carnivorous mammals such as the marsupial lion, using computational engineering techniques and mechanical simulations.

For media interviews contact Colin McHenry, University of Newcastle, on (02) 4921 5404.