Dodos, giant tortoises and other ancient Malagasy animals were wiped out by the deadly combination of human activity and a MEGADROUGHT 1000 years ago
- Researchers studied 8,000 years of climate data from rock and soil samples
- They found evidence of repeated megadroughts on the islands during that time
- Megafauna appeared to have survived previous episodes of extended drought
- The one who finally killed them coincided with the appearance of humans
Giant creatures from Madagascar and the Mascarene Islands were killed by a deadly combination of human activity and a megadrought, a mineral sample study found.
The creatures, including dodos and giant turtles, survived through millennia of repeated droughts until humans arrived and eventually wiped them out.
Both islands suffered a ‘megafauna crash’ between 1500 and 500 years ago, when large species of animals and birds were exterminated at about the same time.
Researchers from the University of Innsbruck studied climate data and mineral deposits in Madagascar and the Mascarene Islands dating back 8,000 years.
Experts found that it was probably a ‘double whammy’ of increased human activity combined with a particularly serious ‘megadrought’ that judged the creatures.
The creatures, including dodos and giant turtles, survived for millennia with repeated droughts until humans arrived and eventually wiped them out, authors claim
Almost all of Madagascar’s megafauna – including the famous Dodo bird, gorilla-sized lemurs, giant turtles and the 9-foot-tall Elephant – disappeared.
Theories suggested that this could have been due to a changing climate, severe droughts over long periods – or from overhunting of humans when they arrived.
The Mascarene Islands, just east of Madagascar, are of particular interest because they are among the last islands on earth colonized by humans.
‘Excitingly collapsed the islands’ ‘megafauna in just a few centuries after human settlement’ according to the research group.
The large, charismatic animals that inhabited the islands managed to survive repeated breakthroughs for thousands of years – before humans arrived.
The team says a combination of hunting, deforestation and other man-made stressors may have contributed significantly to the extinction.
While both Madagascar and the Mascarene Islands are considered ‘hot spots’ for biodiversity, these islands have lost most of their endemic animals.
Lead researcher Hanying Li and colleagues reconstructed millennial-scale climate trends in calcite deposits from La Vierge Cave in Rodrigues, Mascarene Islands.
They stated that these deposits represent the region’s climatic record more broadly – rather than just for that island.
Using these proxy data, the researchers defined periods of dry and wetter conditions and observed several longer and more severe drought trends throughout the late Holocene than the period in which the megafauna died.
This suggests that the climate and severity of mega-formations had been much worse in various places in the past than when the creatures became extinct.
Researchers rule out climate change as the sole cause and instead suggest that the impact of human colonization was a major contributor.
Almost all of Madagascar’s megafauna – including the famous Dodo bird, gorilla-sized lemurs, giant turtles and the 9-foot-tall Elephant bird disappeared between 1500 and 500 years ago
The latest of drought trends in the region began about 1500 years ago at a time when archaeological and proxy records began to show definitive signs of increased human presence on the island.
Ashish Sinha, a professor of earth sciences at California State University, said they can not say for certain human activity was the ‘last straw that broke the camel’s back’, but records suggest that was the case.
This is because megafauna had shown a resilience to previous climate fluctuations, suggesting that an additional stressor contributed to their extinction.
“Many pieces are still missing to solve the mystery of the megafauna collapse in full. This study now provides an important climatic connection with several millennia for megafaunal extinction, ‘says Ny Rivao Voarintsoa from KU Leuven in Belgium.
The results are published in the journal Science Advances.
WHY THE GOOD DODO RELEASED?
Not much is known about the life of dodos despite the notoriety that comes with being one of the world’s most famous extinct species in history.
The bird gets its name from the Portuguese word for fool, after colonialists mocked its apparent lack of fear of human hunters.
The 3 meter high bird was wiped out by visiting sailors and the dogs, cats, pigs and monkeys they brought to the island in the 17th century.
Because the species lived in isolation on Mauritius for millions of years, the bird was fearless, and its inability to fly made it easy prey.
The last confirmed observation was in 1662, after Dutch sailors first discovered the species only 64 years earlier in 1598.
When it had evolved without any predators, it survived in bliss for centuries.
The arrival of human settlers to the islands meant that the number rapidly declined as it was eaten by the new species that invaded its habitat – humans.
Sailors and settlers ravaged the docile bird, and it went from a successful animal that possessed an environmental niche without predators to extinction in a single lifetime.
Other birds, such as the kakapo in New Zealand, also evolved to be equally fearless, plump and sluggish.
As humans spread throughout the world, they also decimated the number of birds in their population.
Kakapo is now an endangered species.
The dodo (left) is now extinct after an attack on hungry sailors from the 17th century destroyed the population of the docile, fearless birds. Kakapo (right) is a similar flightless, fearless bird that is now struggling to survive and is currently threatened