The most ferocious biters among mammals aren't lions, tigers, or wolves, but meat-eating marsupials, a new study says.

　　Scientists in Australia estimated, for the first time, the bite force of a wide range of mammalian carnivores. The researchers found that, pound for pound, the Tasmanian devil is the most powerful biter alive today.

　　Studying fossils, the researchers reached a similar verdict for extinct meat-eaters, noting that marsupial lions scored the highest overall bite force. The 200-plus-pound (100-plus-kilogram) creatures last roamed Australia about 30,000 years ago.

　　The study team adds that these "hypercarnivores" were once the dominant predators on the continent, occupying a similar niche filled by saber-toothed cats in North and South America.

　　Researchers analyzed the skulls of 39 living and extinct species to calculate the bite force delivered by the canine teeth of mammalian carnivores. Each animal's bite strength was then adjusted for its estimated body mass to give a relative value that could be compared between species.

　　The scientists published their findings last week in the London-based science journal, Proceedings of the Royal Society (Series B).

　　Stephen Wroe, a paleontologist and mammal expert at the University of Sydney in Australia, led the study. "The predatory capabilities of the [Tasmanian] devil are often underrated," he said.

　　"A 6-kilogram [13-pound] devil can kill a 30-kilogram [66-pound] wombat."

　　Similarly, the study suggests that pouched predators that roamed Australia until around 30,000 years ago delivered a bite almost as powerful as modern lions nearly three times their size.

　　"A marsupial lion averaging around 100 kilograms [220 pounds] could develop a bite force approaching that of the biggest living lion at around 250 kilograms [550 pounds]," Wroe said.

　　Placental mammals (mammals whose young develop in the womb) also claim some vice-jawed super-killers. They include African hunting dogs, jaguars, and clouded leopards.

　　Among this group, the extinct dire wolf (a giant relative of living wolves) claimed the most powerful bite force relative to its size. The ancient wolf had a relatively broader, shorter head than the modern-day gray wolf. Along with bigger teeth and a studier body, the dire wolf also had a smaller braincase.

　　Wroe and his colleagues noted similar adaptations in Australia's extinct marsupial lion.

　　Previous studies indicate that expanded brain volume in predatory mammals leaves less room for jaw muscles. So does a smaller brain signal a stronger bite force? "As a generality, this is what our findings suggest," Wroe said. "But we need to do more work before we can be sure."

　　The paleontologist says the brain volume of placental carnivores is about two and a half times larger, on average, than that of pouched carnivores. This may help explain why many marsupials register so high on the study's relative bite scale.

　　The study lends further weight to Wroe's claim that marsupial lions were far more fearsome than many scientists previously thought.