Guest post by David Middleton
What rapidly wiped out Madagascar’s megafauna between 700 and 1000 AD?
Climate change? Meteors? Over-hunting? President Donald J. Trump? Nope. It appears that agriculture may have killed the beasts…
Last of the giants: What killed off Madagascar’s megafauna a thousand years ago?
March 29, 2019
Giant 10-foot-tall elephant birds, with eggs eight times larger than an ostrich’s. Sloth lemurs bigger than a panda, weighing in at 350 pounds. A puma-like predator called the giant fosa.
They sound like characters in a child’s fantasy book, but along with dozens of other species, they once really roamed the landscape of Madagascar. Then, after millions of years of evolution in the middle of the Indian Ocean, the populations crashed in just a couple of centuries.
Scientists know that over the past 40,000 years, most of Earth’s megafauna – that is, animals human-size or larger – have gone extinct. Woolly mammoths, sabre tooth tigers and countless others no longer roam the planet.
What’s remarkable about the megafaunal crash in Madagascar is that it occurred not tens of thousands of years ago but just over 1,000 years ago, between A.D. 700 and 1000. And while some small populations survived a while longer, the damage was done in a relatively short amount of time. Why?
Over the last three years, new investigations into climate and land use patterns, human genetic diversity on the island and the dating of hundreds of fossils have fundamentally changed scientists’ understanding of the human and natural history of Madagascar. As two paleoclimatologists and a paleontologist, we brought together this research with new evidence of megafaunal butchery. In doing so we’ve created a new theory of how, why and when these Malagasy megafauna went extinct.
If there was no obvious climate shift and humans lived alongside and sustainably hunted the megafauna for up to 9,000 years, what could have triggered the population crash?
The abrupt land use change might hold some clues.
Evidence for simultaneous increases in grassland, fires, and cows and other domesticated animals points to a sudden change in Malagasy lifestyle: the introduction of cattle husbandry and slash-and-burn agriculture known locally as Tavy. Here, forests are cut down to make space for rice paddies, and grassland burned to promote the growth of nutritious seedlings for cow fodder.
This move away from foraging and hunting toward farming meant the land could support more people. The result was a rapid rise in the size of the human population – and that’s what we conclude spelled disaster for the megafauna.
Here lies the contradiction of the situation: Hunting megafauna for survival became less important as people could rely on their agriculture and livestock. But cut marks on fossil bones indicate that hunting didn’t altogether stop just because people had other food sources. It turns out that the impact on the megafauna of larger human populations hunting just to supplement their diet was greater than the impact of smaller human populations relying more heavily on the native animals as a vital food source.
Aepyornis titan (the “elephant bird”) was one of Madagascar’s more noteworthy Late Quaternary megafauna. It looked like something out of the movie, Mysterious Island…
You would think that Aepyornis might have been hunted into extinction… With drumsticks bigger than a bundle of Louisville Sluggers, a bucket of the Colonel’s fried elephant bird would have easily fed a family of four… dozen. However, it appears that human predation was mostly limited to “egg-poaching”… I imagine it would have taken several hours to poach an egg 160 times the volume of a chicken egg.
Setting aside the idiotic comment about the current “mass extinctions,” Yale anthropology grad student Kristina Guild Douglass had an interesting discussion of the giant elephant bird in this Yale University article…
“As the world enters into a new wave of mass extinctions, which is starting to announce itself with the precarious status of species like the black rhino, it is very important to understand how human action is linked to ecology, evolution, and climate change,” says Kristina.
One focus of her dissertation project is the interaction between people and the now-extinct giant elephant bird, Aepyornis, the largest of which stood over 10 feet tall, weighed up to 800 pounds, and laid eggs 160 times the volume of a chicken egg. The National Geographic Society in Washington has an intact subfossilized egg that contains an embryonic skeleton of the unborn bird.
“When they died out is a central question of my research,” she says. “There may have been five or more species of these birds in Madagascar, and each species likely had a distinct extinction trajectory.” The last historical sighting of an Aepyornis was in the 17th century, and most of the radiocarbon-dated remains hover around the 12th century or earlier, but Kristina has found a specimen that may be much younger – in fact, if she can confirm the date, it would be the youngest elephant bird remains ever discovered.
“Why they died out is also a complex question, but the answer is somewhere in the combination of climate change, changes in vegetation patterns, and human predation,” she says. “From my excavations, however, human predation seems to be limited to egg-poaching. I have not found any evidence that people hunted adult birds, which was one of the major drivers of extinction for giant flightless birds elsewhere, like the moa in New Zealand.”Yale GSAS
I wonder if there’s any evidence that Aepyornis might have been the predator rather than the prey?
Apparently not. Fortunately for Madagascar’s early human settlers, Aepyornis most likely subsisted on low-hanging fruit (literally)…
07 of 10
The Elephant Bird Was Slightly Shorter than the Thunder Bird
There’s little doubt that Aepyornis was the heaviest bird that ever lived, but it wasn’t necessarily the tallest–that honor goes to Dromornis, the “Thunder Bird” of Australia, some individuals of which measured nearly 12 feet tall. (Dromornis was much more slenderly built, however, only weighing about 500 pounds.) By the way, one species of Dromornis may yet wind up being assigned to the genus Bullockornis, otherwise known as the “Demon Duck of Doom.”
08 of 10
The Elephant Bird Probably Subsisted on Fruits
You might think a ratite as fierce and feathery as the Elephant Bird would spend its time preying on the smaller animals of Pleistocene Madagascar, notably its tree-dwelling lemurs. As far as paleontologists can tell, however, Aepyornis contented itself with picking off low-lying fruit, which grew in abundance in this tropical climate. (This conclusion is supported by studies of a smaller extant ratite, the cassowary of Australia and New Guinea, which is well-adapted to a fruit diet).
09 of 10
The Elephant Bird Was Doomed to Extinction by Human Settlers
10 of 10
It May Be Possible to “De-Extinct” the Elephant Bird
[…]ThoughtCo. 10 Facts About the Elephant Bird
It’s amazing that humans seem to be responsible for every species extinction since humans evolved. It makes one wonder how species were ever able to go extinct without our help… Is it time for George Carlin? Warning: Lots of F-bombs…
Arcane American Pop Culture References
A bucket of the Colonel’s fried
elephant bird chicken.