Animals That Start With O

24 animals Animals and nature Checked 9 Oct 2026

Here are 24 animals that start with O, each with a one-line description so you can tell what it is. The best-known ones come first, then the full list in A to Z order.

O gives 24 animals, and most children can name owl, octopus and ostrich right away. Otter, ox and orangutan are also familiar from storybooks.

The rest of the page holds real curiosities. The okapi looks part zebra but is related to the giraffe, and the olm is a pale cave salamander. The oarfish is a long, ribbon-shaped ocean fish. Several names start with oyster, including the oyster crab and oyster catcher. The ocelot is a spotted wild cat of the Americas.

Animals starting with O: 24
Best known: owl, oyster
Longest name: oriental cockroach
Most are: mammals

Best-known animals that start with O

The ones most people will recognise, good for school lists, quizzes and games.

owl
oyster
ox
octopus
otter
ostrich
orca
osprey
orangutan
oryx
opossum
oriole
ocelot
oarfish
okapi
olm
orb weaver
oxpecker

All animals that start with O

#	Name	What it is	Type
1	oarfish	very long silvery deep-sea fish with a red fin	fish
2	ocean perch	large fish of northern Atlantic coasts of America and Europe	fish
3	ocelot	nocturnal wildcat of Central America and South America having a dark-spotted buff-brown coat	mammal
4	octopus	bottom-living cephalopod having a soft oval body with eight long tentacles	mollusc
5	oil beetle	any of various beetles that exude an oily substance from the leg joints that deters enemies	insect
6	okapi	African forest animal related to the giraffe with striped legs	mammal
7	olive ridley	olive-colored sea turtle of tropical Pacific and Indian and the southern Atlantic oceans	reptile
8	olm	blind pale salamander living in European caves	amphibian
9	opossum	nocturnal arboreal marsupial having a naked prehensile tail found from southern North America to northern South America	mammal
10	orangutan	large long-armed ape of Borneo and Sumatra having arboreal habits	mammal
11	orb weaver	spider that spins round wheel-shaped webs	other
12	orca	predatory black-and-white toothed whale with large dorsal fin; common in cold seas	mammal
13	oriental cockroach	dark brown cockroach originally from orient now nearly cosmopolitan in distribution	insect
14	oriole	mostly tropical songbird; the male is usually bright orange and black	bird
15	oryx	large African antelope with long straight nearly upright horns	mammal
16	osprey	large harmless hawk found worldwide that feeds on fish and builds a bulky nest often occupied for years	bird
17	ostrich	fast-running African flightless bird with two-toed feet; largest living bird	bird
18	otter	freshwater carnivorous mammal having webbed and clawed feet and dark brown fur	mammal
19	owl	nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes	bird
20	ox	an adult castrated bull of the genus Bos; especially Bos taurus	mammal
21	oxpecker	African bird that eats ticks off large animals	other
22	oyster	marine mollusks having a rough irregular shell; found on the sea bed mostly in coastal waters	mollusc
23	oyster catcher	black-and-white shorebird with stout legs and bill; feed on oysters etc.	bird
24	oyster crab	tiny soft-bodied crab living within the mantle cavity of oysters	crustacean

Mammals that start with O

ox
otter
orca
orangutan
oryx
opossum
ocelot
okapi

Birds that start with O

owl
ostrich
osprey
oriole
oyster catcher

Fish that start with O

oarfish
ocean perch

Insects that start with O

oil beetle
oriental cockroach

Molluscs that start with O

oyster
octopus

Other animals that start with O

orb weaver
oxpecker

Questions people ask

How many animals start with O?

This list has 24 animals starting with O, from well-known ones like owl, oyster, ox to rarer kinds.

What animals start with O?

Well-known examples are owl, oyster, ox, octopus, otter, ostrich, orca, osprey.

What mammals start with O?

ox, otter, orca, orangutan, oryx.

What birds start with O?

owl, ostrich, osprey, oriole, oyster catcher.

What fish start with O?

oarfish, ocean perch.

Source: Princeton WordNet, a public dictionary database, reviewed by our editors to keep only clear, real members of the list. Meanings are short dictionary glosses.

See every letter on one page: animals A to Z