* Streamlined body shape: This reduces drag and makes swimming more efficient. Think of dolphins, seals, and whales.
* Flippers or webbed feet: These act as paddles for propulsion through the water.
* Thick layer of blubber or fur: Provides insulation against cold water temperatures.
* Nostrils located on top of the head: Allows the animal to breathe while keeping most of its body submerged.
* Ability to hold their breath for extended periods: Necessary for diving and foraging in deep water.
* Modified lungs: Some aquatic mammals have lungs that can collapse to minimize buoyancy.
* Salt glands: These help to excrete excess salt that is ingested from seawater.
* Flukes or tails: Powerful tails used for propulsion in some aquatic mammals.
These are just a few examples, and the specific adaptations will vary depending on the species and the specific environment it inhabits.