Sabretooth tigers hunted in packs

By James Morgan Science reporter, BBC News

Sabretooth "tigers" hunted in packs, sharing the spoils among themselves

Forget their ferocious fangs - sabretooth "tigers" were social animals who lived in family prides, like lions today, according to UK and US experts.

The abundance of S.fatalis fossils in Californian tar seeps suggests they were packs of scavengers, lured in by the distress calls of trapped prey.

Research in Africa found that audio playbacks of prey sounds attract social carnivores, but not solitary hunters.

This suggests S.fatalis was social too, claims the Royal Society journal study.

Jaw dropping

The so-called sabretooth tiger - Smilodon fatalis - is famous for its extremely long canine teeth, which reached up to seven inches and extended below the lower jaw.

This extinct cat was more likely to roam in formidable gangs, than as a secretive solitary animal. Dr Chris Carbone, Zoological Society of London

But although commonly called "tigers", due to their size, the species is actually part of a different subfamily, and they lived very differently.

While sabretoothed "tigers" were powerful predators, they were social beasts, rather than skulking loners, according to Dr Chris Carbone, a research fellow of the Zoological Society of London.

He said: "The extinct sabretoothed cat, Smilodon fatalis, has been something of an enigma, with almost nothing known of its behaviour.

"This research allowed us... to conclude that this cat was more likely to roam in formidable gangs, than as a secretive solitary animal."

S.fatalis - one of many sabretooth cat species - lived between 1.6 million and 10,000 years ago, in North and South America.

Many Smilodon fossils have been found in the Late Pleistocene era tar seeps at Rancho La Brea, California - apparently lured to their fate by the calls of trapped, dying herbivores.

In fact, the fossils are so numerous, many palaeontologists now believe the cats were pack hunters, who came to scavenge prey and share the spoils.

The cats lived in prides similar to modern day lions, research suggests

Cat calls

In search of further evidence, Dr Carbone and colleagues looked at the behaviour of modern day carnivores, in the Serengeti region of Tanzania and the Kruger National Park, South Africa.

Big cats were lured to sites using audio "playbacks" of prey in distress, or the sounds of lions and hyenas.

The playbacks attracted large numbers of social carnivore species. Lions and spotted hyenas made up 84% of the individuals attending. But solitary carnivores, of all sizes, were rare.

Overall, social carnivores attended the playbacks approximately 60 times more often than would be expected, based on their abundance relative to other carnivore species in the regions.

The researchers compared these to the carnivore species drawn into the tar seeps, apparently by the sounds of prey.

Again, they found that two species appear to dominate. The presumably social dire wolf (51%) and Smilodon fatalis (33%) made up 84% of the carnivores in the tar seeps.

"The striking similarities between the playbacks and the fossil record support the conclusion that Smilodon was social," said Dr Carbone.

Social animals

"[Sabretooths] were dependent on scavenging as a food source and are likely to have evolved more complicated social organisation in order to optimise their caloric intake."

Professor Alan Turner, an expert in carnivore evolution, from Liverpool John Moores University, said: "These findings make sense when you look at the full picture.

"In the tar seeps, you find so many sabretooth fossils. There is almost one predator for every prey.

"The implication is that several carnivores were attracted to each prey animal. Logically, these predators were not all coming from different territories.

"We now have a whole battery of evidence - from the fossil record to modern ecological studies - all suggesting sabretooths were social.

"We can't say the case is closed, but we have some pretty strong indications."

The research, published in The Royal Society's journal Biology Letters, involved scientists from the University of California, Tshwane University of Technology and University of Pretoria.