Here you’ll find 18 Mammals that start with O that begin with O, organized from “Ocelot” to “Owston’s palm civet”. They include carnivores, primates, and small mammals, useful for classroom lists, field guides, and quick species reference.
Mammals that start with O are species whose common English names begin with the letter O. Many are named for appearance or place, and the ocelot is a well-known cultural example.
Below you’ll find the table with Common name, Scientific name, Order, and Habitat.
Common name: The everyday English name used for each species, so you can quickly recognize or search for it.
Scientific name: The accepted Latin binomial lets you find exact species information and cross-check databases and field guides.
Order: The taxonomic order shows broader biological relationships, helping you group species by shared traits and evolution.
Habitat: A concise habitat label (forest, marine, desert, urban, etc.) helps you understand typical ecosystems where the species live.
Mammals that start with O
| Name | Scientific name | Order | Habitat |
|---|---|---|---|
| Opossum | Didelphis virginiana | Didelphimorphia | Forest |
| Orangutan | Pongo pygmaeus | Primates | Forest |
| Orca | Orcinus orca | Cetacea | Marine |
| Ocelot | Leopardus pardalis | Carnivora | Forest |
| Okapi | Okapia johnstoni | Artiodactyla | Forest |
| Olive baboon | Papio anubis | Primates | Grassland |
| Oncilla | Leopardus tigrinus | Carnivora | Forest |
| Olingo | Bassaricyon gabbii | Carnivora | Forest |
| Olinguito | Bassaricyon neblina | Carnivora | Montane |
| Oriental small-clawed otter | Aonyx cinereus | Carnivora | Freshwater |
| Otter civet | Cynogale bennettii | Carnivora | Freshwater |
| One-horned rhinoceros | Rhinoceros unicornis | Perissodactyla | Grassland |
| Onager | Equus hemionus | Perissodactyla | Desert |
| Oribi | Ourebia ourebi | Artiodactyla | Grassland |
| Oldfield mouse | Peromyscus polionotus | Rodentia | Grassland |
| Oriental giant squirrel | Ratufa bicolor | Rodentia | Forest |
| Olympic marmot | Marmota olympus | Rodentia | Montane |
| Owston’s palm civet | Chrotogale owstoni | Carnivora | Forest |
Descriptions
Opossum
North America’s only marsupial, often called “opossum.” Nocturnal omnivore known for “playing dead” and adaptability to urban areas.
Orangutan
Great ape native to Borneo, arboreal and highly intelligent, with long arms and solitary habits; critically endangered due to habitat loss.
Orca
Also called the killer whale, this large, black-and-white dolphin is a top ocean predator and lives in social pods worldwide.
Ocelot
Medium-sized spotted cat of the Americas, nocturnal and elusive; excellent climber that preys on small mammals and birds.
Okapi
A shy, forest-dwelling relative of the giraffe endemic to the Congo Basin with zebra-like leg stripes and a long, prehensile tongue.
Olive baboon
Widespread African primate that lives in large, complex troops; omnivorous and highly adaptable across savanna and woodland.
Oncilla
Tiny spotted wild cat from Central and South America, nocturnal and arboreal, often weighing under 3–4 kg.
Olingo
Nocturnal, tree-dwelling mammal related to kinkajous, found in Central and South American forests; eats fruit and insects.
Olinguito
Small, teddy-bear–like carnivore discovered in Andean cloud forests; nocturnal frugivore that lives in trees.
Oriental small-clawed otter
The world’s smallest otter, social and dexterous, living in Southeast Asian rivers, mangroves and wetlands.
Otter civet
Rare, semiaquatic civet of Southeast Asia that feeds largely on crabs and fish and is threatened by habitat loss.
One-horned rhinoceros
Also called the Indian rhino, a large grassland grazer with a single horn and thick skin folds; vulnerable but protected in reserves.
Onager
A wild Asian ass adapted to arid plains and deserts, swift and historically widespread but now fragmented and threatened.
Oribi
Small, graceful antelope of African grasslands known for its leaping escape behavior and preference for open habitats.
Oldfield mouse
Small North American mouse that lives in coastal dunes and grasslands; notable for localized subspecies and burrowing habits.
Oriental giant squirrel
Large tree squirrel of Southeast Asia with bold coloration; diurnal and mainly herbivorous in tropical forests.
Olympic marmot
Large marmot endemic to Washington’s Olympic Mountains; lives in colonies, hibernates and is a regional conservation icon.
Owston’s palm civet
Small, secretive civet from parts of Southeast Asia; nocturnal and forest-dependent, threatened by hunting and deforestation.
