* Dolphins: These are closely related to whales, and are also found in the ocean.
* Porpoises: Similar to dolphins, but with a more stout body and smaller dorsal fin.
* Sea lions and seals: These are pinnipeds, which means they have flippers for swimming and spend time both in and out of the water.
* Walruses: Large pinnipeds with tusks, found in Arctic waters.
* Manatees and dugongs: These are herbivorous marine mammals found in tropical waters.
* Sea otters: The smallest marine mammal, they are found in the Pacific Ocean.
* Polar bears: While they spend a lot of time on land, they are excellent swimmers and rely on the sea for food.
So, while whales are certainly a prominent group of water mammals, they are not the only ones!