In a 100 mile race. what mammal would win the race

All mammals would be in their element.

Bats, since flying is the fastest way to go from point A to point B.

In the ocean, it is probably the dolphin.

On land, it would probably be the kangaroo, since their mode of locomotion is very efficient and fast at the same time.

You didn't say which animals would be taking part in this race... And a hundred miles is a long way to go for any animal...