The largest mammal on water is a blue whale, which grows up to 108 feet in length.
The largest mammal on land is the African elephant, which grows up to 13 feet tall.
The smallest mammal on water is a sea otter, which can grow from 100-150 centimeters.
The smallest mammal on land is a Kitti's hog-nosed bat, better known as the bumblebee bat, only grows up to 1.2 inches!