Mark Seaman, age 11, of Pittsfield, Mass., for his question:

WHEN DID THE GROUND SLOTH LIVE?

Ground sloth is the name of a huge, extinct animal of the sloth family. It lived about 1 million years ago and roamed over what is ,now North and South America.
The largest ground sloth was about 20 feet long and nearly as tall as an elephant. Scientists say it must have been able to stand on its hind legs to reach high branches and leaves. It ate only plants. Unlike present day sloths, it did not climb trees.
The animal had huge bones, heavy back legs and a strong tail. The front feet had long claws placed so that the animal must have walked on its knuckles, with only the outer edge of the foot resting on the ground.
The ancestors of the ground sloths lived in trees and used their hooked claws to hang from branches.
At first the ground sloth lived only in South America. But during the Ice Age, these animals also lived in what is now the United States. It wasn't long after this period that the ground sloth became extinct.