Evolution Diary

Humans, not climate change, were responsible for the extinction of giant “kangaroos” and other massive marsupials in Tasmania more than 40,000 years ago, according to new research.

The 1,000-pound (500-kilogram) prehistoric ground-sloth-like marsupial depicted here—Palorchestes azael—was among a handful of Tasmanian megafauna species driven to extinction by human activity more than 40,000 years ago, new research says.

Hunting on the Australian island exterminated several prehistoric animals, including the kangaroo-like beasts, marsupial “hippopotamuses,” and leopard-like cats, a team of scientists announced.

The giant kangaroo-like Protemnon anak, a long-necked leaf browser, survived on Tasmania until at least 41,000 years ago—much later than previously believed and up to 2,000 years after the first human settlers are believed to have arrived—according to new radiocarbon and luminescence dating of fossils, some of which were accidentally found by cavers.

Previous studies had concluded that Tasmania’s giant beasts had already disappeared by the time humans crossed a temporary land bridge to the island 43,000 years ago. These studies blamed the extinctions on climate change—including the last ice age—instead.

The new findings appear this week in the journal Proceedings of the National Academy of Sciences.

Marsupial Menagerie

Six other giant prehistoric Tasmanian species survived the climate change of the time and likely existed until the arrival of humans, although the animals’ remains were not specifically dated to the time humans are believed to have been on the island, according to the study.

The other species include “three kangaroos that would have been in the 220-pound (100-kilogram) size range,” said team member Tim Flannery of Australia’s Macquarie University.

“There was a marsupial leopard, which was probably 100 to 220 pounds [50 to 100 kilograms] in weight,” he said.

“There was also what I would call a marsupial ground sloth that weighed several hundred kilograms at least, and perhaps in excess of 1,000 pounds (500 kilogram).

“And then a thing that you might want to call a marsupial hippopotamus, or a marsupial tapir, which would have weighed about 1,000 pounds (500 kilograms).”

Studies have found that Tasmania and present-day Victoria state, on the nearby Australian mainland, shared a similar climate back then, Flannery said

About 90 percent of mainland Australian megafauna disappeared about 46,000 years ago, soon after humans first settled the continent, studies have found.

Flannery said these extinctions were mirrored in Tasmania 3,000 years later, when the “Bass Strait dried up and a land bridge formed between Victoria and Tasmania, allowing [people] in.”

Extinctions of large animals were “one of the key signatures, if you like, of the arrival of humans,” he said, naming other places the phenomenon likely occurred.

“In the Americas 13,000 years ago, the same thing happened. In Madagascar 2,000 years ago, the same thing. New Zealand 1,000 years ago, the same thing.”

On Caribbean islands, he said, “giant sloths survived for about another 6,000 or 8,000 years after their extinction date on the mainland. Why? Because people hadn’t gotten to those islands. Now we are seeing the same thing with Tasmania.”

Easy Prey

Evidence points to a rapid extermination that may have occurred within a thousand years, Flannery said.

“We have no evidence of any sort of specialized hunting technology at all. It’s quite likely that these things didn’t recognize humans as a threat, so perhaps a wooden spear or a club was enough to kill them.”

Gavin Prideaux, a paleontologist at Flinders University in Australia, said that, while Aboriginal people weren’t known to have used stone spear tips until around 5,000 to 6,000 years ago, they used fire to toughen several species of Australian hardwoods to make formidable spears.

“This is a first major step towards understanding what happened in Tasmania,” Prideaux said.

However, only the giant, kangaroo-like Protemnon has been shown conclusively to have co-existed with people, he said.

“There may very well be others, but at the moment, that’s where it stands.”

Prideaux added that many more megafauna fossils are likely to be found on Tasmania, “because there has been so little exploration. We need to find those, get them dated, and build up a picture.”News from National Geographic

The 1,000-pound (500-kilogram) prehistoric ground-sloth-like marsupial depicted here—Palorchestes azael—was among a handful of Tasmanian megafauna species driven to extinction by human activity more than 40,000 years ago, new research says.

Hunting on the Australian island exterminated several prehistoric animals, including the kangaroo-like beasts, marsupial “hippopotamuses,” and leopard-like cats, a team of scientists announced.

The giant kangaroo-like Protemnon anak, a long-necked leaf browser, survived on Tasmania until at least 41,000 years ago—much later than previously believed and up to 2,000 years after the first human settlers are believed to have arrived—according to new radiocarbon and luminescence dating of fossils, some of which were accidentally found by cavers.

Previous studies had concluded that Tasmania’s giant beasts had already disappeared by the time humans crossed a temporary land bridge to the island 43,000 years ago. These studies blamed the extinctions on climate change—including the last ice age—instead.

The new findings appear this week in the journal Proceedings of the National Academy of Sciences.

Marsupial Menagerie

Six other giant prehistoric Tasmanian species survived the climate change of the time and likely existed until the arrival of humans, although the animals’ remains were not specifically dated to the time humans are believed to have been on the island, according to the study.

The other species include “three kangaroos that would have been in the 220-pound (100-kilogram) size range,” said team member Tim Flannery of Australia’s Macquarie University.

“There was a marsupial leopard, which was probably 100 to 220 pounds [50 to 100 kilograms] in weight,” he said.

“There was also what I would call a marsupial ground sloth that weighed several hundred kilograms at least, and perhaps in excess of 1,000 pounds (500 kilogram).

“And then a thing that you might want to call a marsupial hippopotamus, or a marsupial tapir, which would have weighed about 1,000 pounds (500 kilograms).”

Studies have found that Tasmania and present-day Victoria state, on the nearby Australian mainland, shared a similar climate back then, Flannery said

About 90 percent of mainland Australian megafauna disappeared about 46,000 years ago, soon after humans first settled the continent, studies have found.

Flannery said these extinctions were mirrored in Tasmania 3,000 years later, when the “Bass Strait dried up and a land bridge formed between Victoria and Tasmania, allowing [people] in.”

Extinctions of large animals were “one of the key signatures, if you like, of the arrival of humans,” he said, naming other places the phenomenon likely occurred.

“In the Americas 13,000 years ago, the same thing happened. In Madagascar 2,000 years ago, the same thing. New Zealand 1,000 years ago, the same thing.”

On Caribbean islands, he said, “giant sloths survived for about another 6,000 or 8,000 years after their extinction date on the mainland. Why? Because people hadn’t gotten to those islands. Now we are seeing the same thing with Tasmania.”

Easy Prey

Evidence points to a rapid extermination that may have occurred within a thousand years, Flannery said.

“We have no evidence of any sort of specialized hunting technology at all. It’s quite likely that these things didn’t recognize humans as a threat, so perhaps a wooden spear or a club was enough to kill them.”

Gavin Prideaux, a paleontologist at Flinders University in Australia, said that, while Aboriginal people weren’t known to have used stone spear tips until around 5,000 to 6,000 years ago, they used fire to toughen several species of Australian hardwoods to make formidable spears.

“This is a first major step towards understanding what happened in Tasmania,” Prideaux said.

However, only the giant, kangaroo-like Protemnon has been shown conclusively to have co-existed with people, he said.

“There may very well be others, but at the moment, that’s where it stands.”

Prideaux added that many more megafauna fossils are likely to be found on Tasmania, “because there has been so little exploration. We need to find those, get them dated, and build up a picture.”