List of mammals of Guam
# 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:

| 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. |

## 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 EN
         * Guam flying fox, Pteropus tokudae EX
* Family: Emballonuridae
   * Genus: Emballonura
      * Polynesian sheath-tailed bat, Emballonura semicaudata EN (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 EN
            * Bryde's whale, Balaenoptera edeni DD
      * Subfamily: Megapterinae
         * Genus: Megaptera
            * Humpback whale, Megaptera novaeangliae EN
* Suborder: Odontoceti
      * Family: Physeteridae
         * Genus: Physeter
            * Sperm whale, Physeter macrocephalus VU
   * Superfamily: Platanistoidea
      * Family: Kogiidae
         * Genus: Kogia
            * Dwarf sperm whale, Kogia sima DD
      * Family: Ziphidae
         * Subfamily: Hyperoodontinae
            * Genus: Mesoplodon
               * Blainville's beaked whale, Mesoplodon densirostris DD
      * Family: Delphinidae (marine dolphins)
         * Genus: Lagenodelphis
            * Fraser's dolphin, Lagenodelphis hosei LC
         * Genus: Peponocephala
            * Melon-headed whale, Peponocephala electra LC
         * Genus: Feresa
            * Pygmy killer whale, Feresa attenuata DD
         * Genus: Pseudorca
            * False killer whale, Pseudorca crassidens DD
         * Genus: Globicephala
            * Short-finned pilot whale, Globicephala macrorhynchus DD
         * Genus: Orcinus
            * Orca, Orcinus orca DD
