The Cenozoic Era is one of the eras in the geologic time scale.
In this Era, humans first appeared on Earth most likely as cave men (uninvolved).
It is sometimes referred to as the Age of Mammals.
Sabre-toothed cats, cave bears, and woolly rhinoceroses were some of the animals in this era.
The climate was much warmer at that time than it is today.
The Alps, Himalayas, and Rocky Mountains were formed during this era.
Without the dinosaurs, plant life flourished.
As forests thinned, grasses began to spread.