Scientists have estimated that there are 8.7 million animal species on Earth. Some of these are fierce ... varieties of stick ...

The earliest humans emerged about 300,000 years ago. While many of Earth’s earliest life forms have long since gone extinct, some animals have stood the test of time–surviving through mass ...

The class of animals that we refer to as “reptiles ... the most famous of which are the dinosaurs which disappeared from Earth approximately 65 million years ago. Setting dinosaurs aside ...