It is almost impossible to tell exactly how long dinosaurs lived, but educated guesses can be made by studying the lifespans of their descendants. This group includes modern alligators, tortoises, fish and birds. Scienti... More » History Prehistory

Dinosaurs existed during the Mesozoic Era, first appearing around 230 million years ago and dying out about 65 million years ago. However, scientists largely agree that birds are the direct descendants of dinosaurs. If s... More »

Dinosaurs lived on Earth for about 175 million years, until they were entirely wiped out by the K-T extinction event at the end of the Cretaceous Period. They lived during the Mesozoic Era, and examples of dinosaurs can ... More »

Major events during the Jurassic included the further breakup of the supercontinent Pangaea, the development of subtropical conditions and larger dinosaurs. The earliest bird also took flight during the late Jurassic, an... More »

Cavemen lived as far back as 3.7 million years ago. These early ancestors of humans date back to the Tertiary period. More » History Prehistory

The caveman, or homo neanderthalensis, lived in nuclear families during the Pleistocene Epoch in Eurasia around 200,000 to 300,000 years ago, taking shelter in caves and living a rudimentary existence. Fossilized remains... More »

Australopithecus lived between 2.95 and 3.85 million years ago in East Africa, approximately where Tanzania, Kenya and Ethiopia exist today. It is believed that Australopithecus survived as a species for approximately 90... More »