Forelimb Bones Give Away Predation Style of Carnivorous Mammals

Forelimb bone data obtained by two paleobiologists help predict the predation style of a wide variety of carnivorous mammals, particularly the extinct marsupial thylacine, as described in a study published in the Journal of Morphology.

These scientists wanted to determine the hunting style of the marsupial called thylacine - also referred to as the "marsupial wolf" or the "Tasmanian tiger." Their research showed that this Australian dog- and cat-like animal was uniquely unspecialized, and led to the development of a predator classification system simply based off of forelimb bones.

"We realized what we are also doing was providing a dataset or a framework whereby people could look at extinct animals because it provides a good categorization of extant forms," lead author Christine Janis explained in a news release.

For instance, after comparing the scapulas, or shoulder blades, of leopards versus cheetahs, the scientists found that cheetahs are more closely related to predators that evolved for chasing their prey, whereas leopards are more closely related to other cats that evolved for grappling (usually other big cats).

"The main differences in the forelimbs really reflect adaptations for strength versus adaptations for speed," Janis added.

In all, Janis and her co-author Borja Figueirido of the Universidad de Malaga in Spain made 44 measurements on five forelimb bones of 37 species ranging from the Arctic fox to the thylacine. The results allowed them to accurately discern ambush predators from pursuit predators to pouncing predators. Even if they only had one bone available to draw conclusions from, 70 percent of the time their classification was correct.

As for the thylacine, Janis and Figueirido still could not reach a consensus. Some data indicated they were pursuers while others suggested ambushers. However, Janis notes that given their lack of competition there wasn't a real need to be specialized as a certain type of predator.

But for other distinct predators, this new technique can provide a framework for other paleobiologists trying to classify different species