List of mammals of Guam

This is a list of the mammal species recorded in Guam. There are fifteen mammal species in and around Guam, of which two are endangered and one is considered to be extinct.

The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature:

Order: Chiroptera (bats)
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.


 * Family: Pteropodidae (flying foxes, Old World fruit bats)
 * Subfamily: Pteropodinae
 * Genus: Pteropus
 * Mariana fruit bat, Pteropus mariannus
 * Guam flying fox, Pteropus tokudae
 * Family: Emballonuridae
 * Genus: Emballonura
 * Polynesian sheath-tailed bat, Emballonura semicaudata (extirpated from Guam)

Order: Cetacea (whales)
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, forelimbs, and tails modified to provide propulsion underwater.


 * Suborder: Mysticeti
 * Family: Balaenopteridae
 * Subfamily: Balaenopterinae
 * Genus: Balaenoptera
 * Sei whale, Balaenoptera borealis
 * Bryde's whale, Balaenoptera edeni
 * Subfamily: Megapterinae
 * Genus: Megaptera
 * Humpback whale, Megaptera novaeangliae
 * Suborder: Odontoceti
 * Family: Physeteridae
 * Genus: Physeter
 * Sperm whale, Physeter macrocephalus
 * Superfamily: Platanistoidea
 * Family: Kogiidae
 * Genus: Kogia
 * Dwarf sperm whale, Kogia sima
 * Family: Ziphidae
 * Subfamily: Hyperoodontinae
 * Genus: Mesoplodon
 * Blainville's beaked whale, Mesoplodon densirostris
 * Family: Delphinidae (marine dolphins)
 * Genus: Lagenodelphis
 * Fraser's dolphin, Lagenodelphis hosei
 * Genus: Peponocephala
 * Melon-headed whale, Peponocephala electra
 * Genus: Feresa
 * Pygmy killer whale, Feresa attenuata
 * Genus: Pseudorca
 * False killer whale, Pseudorca crassidens
 * Genus: Globicephala
 * Short-finned pilot whale, Globicephala macrorhynchus
 * Genus: Orcinus
 * Orca, Orcinus orca