Fish
Oarfish
World's longest bony fish
Animals that start with O
There are 16 animals that start with the letter O, including the Oarfish, Ocean Sunfish, Oceanic Whitetip Shark, and more. See photos, facts, and full guides for each.
Fish
Ocean Sunfish
The heaviest bony fish
Fish
Oceanic Whitetip Shark
Critically Endangered lord of the open ocean
Mammal
Ocelot
The spotted cat of the Americas
Invertebrate
Octopus
The shape-shifting genius of the sea
Mammal
Okapi
The forest giraffe of the Congo
Mammal
Olive Baboon
Africa's adaptable monkey
Amphibian
Olm
Blind cave salamander of European karst
Mammal
Opossum
North America's only marsupial
Mammal
Orangutan
The great ape of the Southeast Asian rainforest
Mammal
Orca
The ocean's top predator
Insect
Orchid Mantis
The Southeast Asian insect that mimics a flower to lure and ambush prey
Amphibian
Oriental Fire-bellied Toad
The green toad with a warning-red belly
Bird
Osprey
The fish-hunting raptor of coasts and lakes
Bird
Ostrich
The largest and fastest bird on land
Mammal
Otter
The playful, water-loving member of the weasel family
Animals that start with O: FAQs
What animals start with the letter O?
Animals beginning with O include Oarfish, Ocean Sunfish, Oceanic Whitetip Shark, Ocelot, Octopus, and 11 more.
How many animals begin with O?
Our guide currently covers 16 animals whose names start with O.