Thylacine hunted more like a cat than a dog

The enigmatic thylacine hunted more like a tiger than a wolf, new research suggests.

THE NOW-EXTINCT THYLACINE was the largest carnivorous marsupial to roam Australia in modern times. Its pouch, its dog-like head, and its unusual stripes, earned it nicknames such as 'marsupial wolf' and 'Tasmanian tiger', and its scientific name Thylacinus cynocephalus is Greek for 'dog-headed pouched one'.

But Dr Borja Figueirido and Dr Christine Janis, palaeontologists from Brown University in the US, believe that despite its wolf-like appearance, the thylacine may have hunted more like a cat. "I'd always used the term 'marsupial wolf', but when it became apparent that it really wasn't all that wolf-like, the other vernacular name [Tasmanian tiger] seemed more appropriate," says Christine.

In a paper published in Biology Letters this week, the researchers argue the thylacine's elbow joint provides new insights into how the animal hunted and handled its prey.  "We looked at the elbow because that piece of anatomy had already been established as being distinctive between carnivores of different hunting styles," Christine says.

While wolves often hunt in packs, chasing down their prey over large distances, the thylacine's bones suggest it used stealth, surprise and short bursts of speed, like a large cat, to catch its meals.

The skeleton key

Borja and Christine compared eight thylacine elbows with those of 32 other carnivores such as jackals, wolves, Tasmanian devils, pumas, hyenas and panthers. They noticed the thylacine elbow had more in common with the bones in ambushing predators, and was not at all suited to sustained chases.
 
"It's an emblematic animal that is often compared to living wolves today," Borja says. "But living wolves are fast-running predators and by looking at the Tasmanian tiger's bones, it is probable they weren't like that."

Instead, the thylacine elbow joint allowed it to twist its arm in different directions, making it easier to wrestle and kill prey at close range or in a surprise attack. The arms of dog-like species, such as dingoes or wolves, are far less flexible and are usually fixed in a palm-down position, making it easier to run long distances to wear down a target.

"I think with our study we filled an empty space in the knowledge about the hunting behaviour of this animal," says Borja. The researchers also suggest thylacines would have needed flexible arms to crawl into their mother's pouch as babies, preventing them from ever becoming pursuit predators.

Dr Stephen Wroe, a biomechanist from UNSW, says the new research is a significant contribution to existing knowledge about the thylacine's hunting habits. "You can tell a lot about an animal when you look at that sort of [anatomical] detail; it's very specific," he says.

Competing for survival

Humans carry most of the blame for the thylacine's extinction, but there is still debate about the role dingoes played in driving them from the Australian mainland. Stephen believes the thylacine's specialised hunting habits, in competition with the more adaptable dingo, could have been one of the factors leading to its extinction.  
 
But Christine and Borja emphasise more research needs to be done. "We think that the issue of the reasons for extinction in Australia, and the role of the dingo, need to be re-examined in light of the fact that it probably wasn't direct competitive replacement," says Christine.

The pair is hopeful their results will spur more research and help conserve large carnivore species that are still around. The last known thylacine died in captivity in Hobart zoo in 1936. Many sightings of the animal have been reported since, however none have been confirmed.

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