Why did such a formidable predator suddenly die out, more than 2.5 million years ago?

Given their fearsome size, the giant turtles might have been formidable predators themselves.

The protohumans living in the forests had to adapt to living on hostile open plains, where they would have been easy prey for formidable predators such as big cats.

This group became known as the terror birds, and were formidable predators.

These huge animals were clearly formidable predators.