Why did the ancient lazy the size of the elephants become – then it disappeared

A giant lazy with the claws of the edge of the edge and large like elephants of the Asian bull that wandered once on the floor, and a snack on the leaves on the tops of the trees with the pre -gene tongue.

Now, scientists have discovered the reason they were very huge – and why this huge lazy did not abide – with a new study published in sciences.

Today, two types of lazy in Central and southern America are inhabited. But long ago, dozens of lazy types had copied the Americas, along the way from Argentina to Canada. Like modern lazy, it was the younger species. But the larger lazy?

“They seemed like gray bears, but they are five times larger,” Rachel Narduchi, director of the vertebrate fossil science group at the Florida Museum of Natural History and the Claus, in A. statement.

The larger lazy did not do much tree climbing, at risk of falling until their death. Instead, they survived through the terrifying; The largest lazy had a long and sharp claws used to sculpt their own caves from rocky land and rocks. But exactly why they got very large remaining a mystery.

To find out how this lazy became very huge, the researchers analyzed the ancient DNA and compared more than 400 hugs of natural history museums to create a laziness tree. The researchers followed the origin of the lazy to 35 million years. Because scientists were particularly interested in how the lazy obtained its size, they estimated their weight by taking fossil measurements.

The researchers concluded that the previous climate of the Earth was a great factor. Thirty -five million years ago, the modern lazy predecessor, who lived in what Argentina now knew the size of a large dog was almost the size of a large dog. The lazy barely changed in size for 20 million years, and lived on the ground. Then, during the warming period about 16 million years ago, the lazy was adapted to the development of smaller physics because of their need to keep cold.

After that, when the ground cools again – which he was doing and turning off over the past fifty years – the hole began greater and greater. They also started immigration, and they come out of Argentina throughout North and South America, and even Alaska and Canada.

These new habitats have presented challenges faced by the lazy, partly, through forgery. This new size also helped them keep warm and stay safe from predators.

“This would have allowed them to maintain energy, water and travel more efficiently through limited resources,” said Naruchi. “And if you are in the open herbal land, you need protection, and to be the largest providing some of it.”

They reached their fullest size during the ice Ice ages, which spanned nearly 3 million to 12,000 years before their disappearance.

Scientists are not completely sure of the cause of lazy extinction, but they have some guesses. The first people immigrated to the Americas about 20,000 years ago. The oldest larger than the land is likely to become a major and delicious target for the first humans, and the presence on the ground has become a responsibility.

The larger lazy was the first to go, but the lazy trees did not escape safely. Over time, more and more kind of poor lazy trees also became extinct. Two types survived the Caribbean Sea, up to about 4,500 years – until humans wiped them. Now, the lazy in Central and South America maintains, but fortunately it is no longer on the list.