Just a few centuries ago, Madagascar was home to a monstrous creature called the elephant bird. It towered as high as nine feet. Weighing as much as 600 pounds, it was the heaviest bird known to science. You’d need 160 chicken eggs to equal the volume of a single elephant bird egg.

The only feature of the elephant bird that wasn’t gigantic was its wings, which were useless, shriveled arms. Instead of flying, the elephant bird kept its head down much of the time, grazing on plants.

Scientists aren’t precisely sure when this strange creature became extinct, but it probably endured well into our human-dominated age.

In the Middle Ages, Marco Polo heard tales of a huge bird that stalked Madagascar. A French colonial governor of Madagascar wrote in 1658 about a giant bird that lived in the remote parts of the island. Today, scientists are trying to determine when the elephant bird became extinct by estimating the age of its youngest remains. It’s possible the birds were still thundering across Madagascar in the 1800s.