During the Neogene Period sea levels were low a lot because of the effect of constant collisions involving land masses. Later The Polar Ice Caps started to take up more space in the ocean and new mountains traps water as snow and ice. The amount of ice formation caused the sea levels to drop even more.
Many forests were changing into grasslands to suit the cool climate, also animals were having to
start adapting to changes with their food sources. Animals soon developed new ways to digest and take in food, and animals started to evolve more and became faster.
Near the end of the Neogene, Period Earth was locked into an Ice Age.