Formidable kitty: Was the sabre-tooth a pack hunter?
Credit: U.S. National Park Service
SYDNEY: Sabre-tooth tigers hunted in packs, suggests research that compared fossil evidence of the extinct predators with behavioural studies of modern carnivores.
"The extinct sabre-toothed cat (Smilodon fatalis) has been something of an enigma," said British zoologist Chris Carbone from the Zoological Institute of London.
Although little is known of their behaviour, his team's research on the present-day behaviour of large African predators, now hints that sabre-tooths may have "roamed in formidable gangs, rather than as a secretive solitary animal," he said.
A window in time
Sabre-tooths were powerful predators that were stouter than modern lions but almost twice as heavy. They lived in the Americas and went extinct 10,000 years ago.
To better understand their behaviour, Carbone and his team recreated hunting scenes that bore some similarities to those around Californian tar pits where many sabre-tooth remains have been found.
In the Kruger National Park, South Africa, and the Serengeti region in Tanzania, the researchers played recordings of herbivores in distress (sometimes with sounds indicating an attack by hyena or lions) at dusk, dawn, and during the night, and recorded how modern predators responded.
Eighty-five per cent of those predators that responded were large social carnivores: lions, spotted hyenas and African wild dogs. This may be because when competing predators are involved, large groups are more successful at snatching a meal than individuals or smaller groups, the researchers said.
Better scavengers
"Social groups are generally more successful when it comes to scavenging," said Carbone, "hence, the increased proportion of social species compared to other carnivores, both in the modern day playbacks and in the historical tar seep records."
Most sabre-tooth fossils are known from individuals preserved in the La Brea tar pits, in Los Angeles. Acting like sticky flypaper, tar seeps trapped animals within the pits, and their distress calls drew predators, which frequently got stuck and perished themselves.
The predators and prey eventually sunk into the pits and were preserved in the tar, capturing a microcosm of contemporary megafauna.
Carbone and his team argue that re-interpreting these finds in light of the African experiments indicates that sabre-tooth cats occupied a niche of large social carnivore, similar to the lion today.
"Some have argued that Smilodon was solitary because most cats are, and because males and females were similar in size, which is not what we see in the social lion," said co-author Blaire Van Valkenburgh, a palaeontologist at the University of California, Los Angeles.
"Also [the sabre-tooth's] brain is somewhat smaller for its body size than might be expected for a social animal," she said.
Social cues
However, other evidence – such as the fact that sabre-tooth remains are more numerous than some social animals and that many sabre-tooths appeared to have survived serious injuries that would have impaired their ability to hunt – is stacking up in favour of the idea that they hunted in packs.
"This is an interesting piece of work and certainly does produce evidence suggesting that sabre-toothed cats may have been social," commented Hamish McCallum an expert on the marsupial carnivores at the University of Tasmania in Hobart, Australia.
McCallum speculated that if the sabre-tooths were social animals then their unusually large teeth may gave been for social or sexual signalling rather than to help them catch prey.
The study is published in the journal Biology Letters.
