Mary Ellen Marino, age 10, of Niagara‑on‑ the‑Lake, Ont., Canada, for her question:

WHICH WAS THE FIERCEST PREHISTORIC ANIMAL?

Most experts agree that he was a mighty dinosaur. They named him Tyrannosaurus, which means the cruel tyrant. His fossil bones have been found in North America. Here, 100 million years ago, he strode around on his gigantic hind legs, trailing his gigantic tail. Larger animals and maybe fiercer have lived in the sea. But as far as we know, Tyrannosaurus was the largest meat‑eating animal that lived on the land.

He stood up, dangling his smallish arms, to a height of 20 feet, taller than our skyscraper giraffe. His body, including his enormous tail, was 50 feet long and he weighed 10 tons. His huge boxy head was four feet long and his jaws were filled with terrible teeth, as sharp as daggers and six inches long. Tyrannosaurus was famished and fierce. He could run fast, grab and claw, and most of his victims were other dinosaurs, large and small. So far as we know, he was the most ferocious of all the prehistoric animals. Thank goodness he departed from the earth more than 70 million years ago.