There are eight mammal species in the United States territory of American Samoa, of which one is endangered and two are vulnerable.[1] Four of the species found in American Samoa are bats, two are whales, and two are dolphins.
The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature:
| EX | Extinct | No reasonable doubt that the last individual has died. | |
| EW | Extinct in the wild | Known only to survive in captivity or as a naturalized populations well outside its previous range. | |
| CR | Critically endangered | The species is in imminent risk of extinction in the wild. | |
| EN | Endangered | The species is facing an extremely high risk of extinction in the wild. | |
| VU | Vulnerable | The species is facing a high risk of extinction in the wild. | |
| NT | Near threatened | The species does not meet any of the criteria that would categorise it as risking extinction but it is likely to do so in the future. | |
| LC | Least concern | There are no current identifiable risks to the species. | |
| DD | Data deficient | There is inadequate information to make an assessment of the risks to this species. |
The bats' most distinguishing feature is that their forelimbs are developed as wings, making them the only mammals capable of flight. Bat species account for about 20% of all mammals.
The order Cetacea includes whales, dolphins and porpoises. They are the mammals most fully adapted to aquatic life with a spindle-shaped nearly hairless body, protected by a thick layer of blubber, and forelimbs and tail modified to provide propulsion underwater.