This is a list of the mammal species recorded in the Cook Islands. There are seven mammal species in the Cook Islands, of which one is labelled as being a vulnerable species. 
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.
There are over 260 species of carnivorans, the majority of which feed primarily on meat. They have a characteristic skull shape and dentition.