This list includes 11 Mammals that start with O, from “Ocelot” to “Owston’s palm civet”. These species range from small forest-dwelling carnivores to larger nocturnal foragers across tropical and temperate regions. Use this list for quick reference, classroom activities, species identification, and general wildlife study.

Mammals that start with O are species whose common English names begin with the letter O, spanning several mammal families and ecologies. For example, the ocelot appears frequently in Mesoamerican art and folklore as a symbol of agility and stealth.

Below you’ll find the table with common name, scientific name, habitat, and average size (cm).

Common name: The everyday name used for each species, so you can quickly recognize and discuss animals without scientific terms.

Scientific name: The Latin binomial gives precise identity and helps you match the common name to global records.

Habitat: Brief habitat categories show where each mammal lives, so you can understand distribution and likely sightings.

Average size (cm): The typical adult length in centimeters helps you visualize animal scale and compare similar species.

Mammals that start with O

Common nameScientific nameHabitatAverage size (cm)
OcelotLeopardus pardalisforest, savanna78
OncillaLeopardus tigrinusforest48.5
OlinguitoBassaricyon neblinamontane forest (Andean cloud forests)38.5
Olive baboonPapio anubissavanna, woodland60
Olive colobusProcolobus verusforest48
OrcaOrcinus orcamarine700
OribiOurebia ourebisavanna, grassland100
Oldfield mousePeromyscus polionotusgrassland, dunes13.5
Ord’s kangaroo ratDipodomys ordiidesert, grassland10.5
OnagerEquus hemionusdesert, steppe250
Owston’s palm civetChrotogale owstoniforest51.5

Descriptions

Ocelot
Medium-sized spotted wild cat from the Americas, nocturnal and arboreal, found in forests and savannas; conservation concerns vary regionally.
Oncilla
Small, cryptic spotted cat of Central and South American forests; elusive and primarily nocturnal with a slender build.
Olinguito
Small, tree-dwelling carnivoran recently recognized as a distinct species; inhabits cloud forests of the northern Andes.
Olive baboon
Widespread African monkey with a dog-like face, lives in large social troops and adapts well to varied habitats.
Olive colobus
Small West African leaf-eating monkey living in dense rainforests; threatened by habitat loss and hunting.
Orca
Also called killer whale, a cosmopolitan, apex predator in oceans; lives in social pods with varied diets and strong regional cultures.
Oribi
Small, slender African antelope that favors open grasslands; known for agility and solitary or small-group behavior.
Oldfield mouse
Small North American rodent of coastal dunes and grasslands; several subspecies are regionally specialized and conservation-listed.
Ord’s kangaroo rat
Small hopping rodent of western North America, adapted to arid habitats with powerful hind legs and cheek pouches.
Onager
Wild Asian ass native to deserts and steppes; fast, hardy ungulate with declining populations due to hunting and habitat loss.
Owston’s palm civet
Rare small carnivore of Southeast Asian forests, nocturnal and shy; threatened by habitat clearance and hunting.
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