This lesson is perfect for English learners who want to learn more about animals starting with the letter O. You will discover a wide range of animals, including wild animals, domestic animals, sea creatures, insects, birds, and zoo animals. This vocabulary journey will help you expand your knowledge and remember new animal names more easily.
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Animals that Start with O
- Oarfish
- Ocellaris Clownfish
- Ocelot
- Octopus
- Oilbird
- Okapi
- Old English Sheepdog
- Olive Ridley Sea Turtle
- Olm
- Opossum
- Orangutan
- Orb Weaver
- Orca
- Oriole
- Ornate Chorus Frog
- Ornate Hawk-Eagle
- Oryx
- Osprey
- Ostrich
- Otter
- Owl
- Owl Butterfly
- Ox
- Oyster
- Oystercatcher
Common Animals that Start with O | Interesting Facts & Pictures
Oarfish
The world’s longest bony fish, which feeds on tiny plankton.
Ocellaris Clownfish
Clownfish are born male but can change into females. They live in reefs and lagoons near Australia and Southeast Asia.
Ocelot
A wildcat found in the forests of South America and southern North America. It hunts small mammals, birds, and reptiles.
Octopus
They have three hearts and blue blood. Because they have no bones, they can squeeze into very small spaces.
Oilbird
This bird uses echolocation to navigate inside caves where it roosts and nests, from Trinidad and Guyana to Bolivia.
Okapi
These animals belong to the giraffe family. Their tongues are long enough to clean their eyes and ears.
Old English Sheepdog
When this dog breed first came to the United States, it was a common pet among wealthy people.
Olive Ridley Sea Turtle
It is able to sleep underwater for up to two hours before coming up for air.
Olm
An aquatic salamander with translucent skin that lives in caves.
Opossum
Because of their low body temperature and strong immune systems, it is rare for them to carry rabies.
Orangutan
Orangutans are critically endangered due to deforestation. These apes eat fruit, live in trees, and are native to Indonesia and Malaysia.
Orb Weaver
There are over 3,000 species of these spiders, making them the third-largest spider family.
Orca
Also known as the killer whale, orcas are the largest members of the oceanic dolphin family and are apex predators.
Oriole
Unlike many insect-eating birds, orioles can eat spiny or hairy caterpillars.
Ornate Chorus Frog
A small frog found in the southeastern United States, especially in pine woodlands.
Ornate Hawk-Eagle
A brown-and-white eagle with a large crest that rises when the bird becomes excited.
Oryx
A large antelope that can weigh between 220 and 450 pounds.
Osprey
A bird of prey found across the Americas, Europe, Africa, Asia, and Australia.
Ostrich
The world’s largest bird and the fastest bird on land, capable of running up to 43 mph.
Otter
Sea otters have the thickest fur of any animal.
Owl
Owls can rotate their necks up to 270 degrees.
Owl Butterfly
Named for the owl-like eye markings on the underside of their wings. They live in Central and South American rainforests.
Ox
Humans have relied on these strong animals for farm work for about 6,000 years.
Oyster
Their shells consist of two hinged parts. Oysters provide benefits such as serving as food or producing pearls.
Oystercatcher
A large wading bird found along the coasts of Europe, Asia, and North Africa. These birds do not usually eat oysters. Instead, they eat cockles, mussels, and worms.
Animals Beginning with O (by Locations)
Wild Animals that Start with O
- Ocelot
- Okapi
- Orangutan
- Oryx
- Otter
- Ounce (Snow Leopard – archaic term)
- Osprey
- Ostrich
- Owl
- Orca
- Octopus
- Opossum
Related: Wild Animals in English
Domestic Animals Beginning with O
- Ox
- Ostrich
- Old English Sheepdog
- Oriental Shorthair
Related: Farm and Domestic Animals in English
Sea and Ocean Animals that Start with O
- Octopus
- Orca (Killer Whale)
- Oyster
- Ocean Sunfish
- Oceanic Whitetip Shark
- Opah (Moonfish)
- Olive Ridley Sea Turtle
- Orange Roughy
- Oceanic Dolphin
- Ocean Perch
- Ocean Triggerfish
- Ocean Quahog
- Ocean Rainbowfish
- Oceanic Pufferfish
- Oceanic Sea Spider
- Oceanic Saury
- Oceanic Barracuda
- Oceanic Lanternfish
- Oceanic Silverside
- Oceanic Squid
- Oceanic Needlefish
- Oceanic Hornetfish
- Oceanic Bonito
- Oceanic Skipjack
- Oceanic Surgeonfish
- Oceanic Kelpfish
- Oceanic Trumpeter
- Oceanic Whiptail
- Oceanic Dottyback
Related: Sea and Ocean Animals in English
Zoo Animals that Start with O
- Ocelot
- Octopus
- Okapi
- Olive Baboon
- Opossum
- Orangutan
- Oryx
- Ostrich
- Otter
- Owl
- Ox
- Ozark Hellbender
- Osprey
- Orange-winged Amazon
- Orange-headed Thrush
- Orange-bellied Parrot
- Oriental Small-clawed Otter
- Oriental Pied Hornbill
Related: Zoo Animals in English
Animals with O (by Types)
Mammals that Start with O
- Ocelot
- Olingo
- Okapi
- Olive Baboon
- Onager
- Orangutan
- Oribi
- Otter
- Ox
- Ozark Big-eared Bat
Related: Mammals in English
Insects that Start with O
- Oak gall wasp
- Oak leafroller
- Oak leaf skeletonizer
- Oak processionary moth
- Oat bug
- Oatmeal moth
- Ocellate gallinipper
- Ochre mark leafhopper
- Ochreous stink bug
- Odd-legged weevil
- Oil beetle
- Oil palm bunch moth
- Old-house borer
- Oleander aphid
- Oleander caterpillar
- Olive fruit fly
- Olive lace bug
- Olive treehopper
- Onion maggot
- Onion thrips
- Orange assassin bug
- Orange barred sulphur
- Orange bug
- Orange dog (caterpillar)
- Orange mint moth
- Orange oakleaf
- Orange-spotted tiger clearwing moth
- Orchard ermine moth
- Oriental beetle
- Oriental cockroach
- Ornate moth
- Osage orange gall
- Osmia bee
- Ostomyia moth
- Owl fly
- Ox beetle
Related: Insects in English
Birds that Start with O
- Ocellated turkey
- Ochre-breasted antpitta
- Olive-backed sunbird
- Olive-sided flycatcher
- Orange-bellied flowerpecker
- Orange-billed nightingale-thrush
- Orange-breasted bunting
- Orange-breasted green pigeon
- Orange-cheeked waxbill
- Orange-crowned warbler
- Orange-fronted parakeet
- Orange-headed thrush
- Orange-winged amazon
- Oriental bay owl
- Oriental darter
- Oriental honey-buzzard
- Oriental magpie-robin
- Oriental pied hornbill
- Osprey
- Ostrich
- Ovenbird
- Owl finch
- Owlet-nightjar
- Oxford ragwort bee-fly
Related: List of Birds in English
Animals Starting with the Letter “O” for Kindergarten
- Octopus
- Otter
- Ostrich
- Orangutan
- Owl
- Ocelot
- Osprey
- Orca
- Oyster
- Okapi