a platypus
michael phelps!
The dolphin
The largest mammal in the world is the Blue Whale and it is found swimming in oceans.
A manatee is a large swimming mammal that is hunted for food and blubber.
whale
Achtharius, it means mammal swimming as a fish.
The Orca. It can reach speeds of up to 55.5km ph! (34mph)
The Martians
Polar bear is definitely a mammal. Many scientists and zoos classify them as a marine mammal due to the amount of time they spend in the water swimming from ice flow to ice flow looking for seals, but they are mammals who nurse their young like any other mammal.
dolphin
try whales, dolphins, otters, humans, penguins to name but a few....
A poo
No, a Horse is a mammal.