100+ Animals that start with O
Last Updated on November 22, 2021 by
Looking for the best animals that start with O?
Which O animals comes to mind first? Is it Octopus or Orca? In this article we’ll review the top 100 animals that start with the letter O. We’ll cover all the outstanding O animals around.
The letter O includes some of the most interesting creatures in the world!
Have you heard of the Oarfish, Orangutan and Opossum? I bet there are a few O animals you haven’t heard of before!
Discover more of them by studying the various creatures that start with the letter ‘O’ below:
The 15 Outstanding Animals that Start with the Letter ‘O’
Be prepared to be bewildered as you learn more about these 15 animals that are outstanding not only in their kindred but also in the animal kingdom.
This sea creature is one of the longest invertebrates, especially among all fish species. However, they live in the deep parts of the Atlantic Ocean, where sunlight can’t reach them. Surprisingly, the massive and most elongated oarfish ever recorded by the Guinness World Records is 26 feet in length. Oarfish has an orange-crested body, silverish scales covered with dark blotches. Despite its gigantic body, oarfish loves to feed on planktons.
The ocean sunfish is best known for its humongous size and exotic physical features. Its body is oval-shaped with big dorsal and anal fins but has no tail fin, giving the ocean sunfish a flat appearance. You will also notice a bumpy snout and its wide mouth, which even contribute to its peculiarity. It is also named after its routine of basking in the sun when it swims up the surface.
The octopus lives up to its name as it is considered one of the most unique and most intelligent aquatic creatures. It has three hearts that pump blue blood and eight brains that make this marine critter an intelligent being. An octopus also has eight arms with suckers that act as mini suction cups for grasping, traveling, and sensing. Not only that but every appendage is also surrounded by hundreds of millions of neurons, making its eight arms an extension of its central nervous system.
These large bird species are endemic to the northern parts of South America and have been given a unique name due to a tradition of boiling young oilbirds for oil extraction. Oilbirds have medium-length tail feathers, and their bodies are covered with reddish-brown feathers. Since oilbirds are nocturnal beings, they rely on echolocation to forage food and detect predators.
Olive Sea Snake
Some snakes also dominate the underwater world, like the olive sea snake characterized by its smooth pale olive-colored skin. It is a dangerous aquatic critter that hunts its prey along the Australian reefs. Olive sea snakes have distinguishable habits like hiding their tails from light and breathing underwater for up to two hours.
Opossums are medium-to-large marsupials covered with pointed snouts, shaggy hair, and round ears. Most of them live in the woods, staying underneath dug tunnels. Mother opossums also carry their babies in their pouches for five months before allowing them to venture on their own as adult opossums. They may look untamed due to their hissing stance, but they’re non-aggressive creatures.
Another animal that starts with the letter ‘O’ is also one of the most intelligent creatures on earth, and it is no other than the orangutan. This primate has a massive body covered with long reddish-brown hair. However, fewer hair strands grow on their broad forehead and protruding muzzle. They have four strong limbs used for climbing and swinging on trees in the rainforests of Borneo and Sumatra.
Orcas, or commonly known as killer whales, are not whales but are actually dolphins. They have massive bodies of black-and-white skin that helps them blend with the ocean’s color. Meanwhile, each eye is located beside the white slanted speck on their faces. Despite their killer auras, orcas neither attack nor feed on humans.
While orcas are underwater predators, ospreys are large seahawks that prey on fish. They have dark brown feathers covering their back and a white-feathered frontal area. Not only that, but they are migratory birds that can fly from Canada to South America and vice versa every winter.
The tallest and most massive living flightless bird is the ostrich, with a long S-shaped neck, large brown- or black-feathered bodies, and two bendable legs used for running. In fact, a fully-grown ostrich can speed up to 70 kilometers per hour, which is fast enough to race with a car. Ostriches also hold the record of having the largest egg, which is equivalent to 24 chicken eggs.
Otters are small-sized mammals with elongated pale brown-furred bodies and tiny rounded ears. They live near bodies of water since they love to swim and hunt fish. Otters also have long muscular tails used for paddling on the water and defending themselves against predators.
Owls are some of the most vicious predators, especially at nighttime. They don’t have eyeballs because they have two cylindrical-shaped eyes. Despite their immobile eyes, they can still see their surrounding by turning their heads 270 degrees in any direction. Owls can also hunt amidst the darkness due to the tapetum lucidum. This flimsy tissue behind each retina helps reflect light which improves their night vision.
Hamlyn’s monkey or the owl-faced monkey got its name for its face’s uncanny resemblance to an owl. Its elliptical-shaped face and the long white vertical line in the middle of its face contribute to this monkey’s owl-like appearance. This primate’s body and two-thirds of its face are also covered in gray fur with a tinge of green. Unfortunately, their population is vulnerable in Eastern Congo.
Oxen (plural of ox) are large-sized male bovines known for their stocky bodies and muscular strength. However, they are usually castrated to make them docile enough for transporting goods and plowing the field. Oxen also have two large curvy horns that grow inward or outward. Some oxen are hairy, while others have a coat that sticks on their skin.
Oysters are mollusks that have an asymmetrical-shaped and pale grey exoskeleton with a porcelain surface on the inside. Not only are oysters considered popular seafood, but they are also cultivated for their pearls. When a parasite, debris, or irritant penetrates the shell, it crystallizes calcium carbonate into pearls. So, where can you find oysters? They inhabit shallow coastal areas and bays where you can spot them easily in these areas, especially during low tide.
Animals with Not-so Ordinary Names that Start with the Letter ‘O’
Their odd names will surely help you remember them as you get to discover multiple animal species.
- Ocellated Frogfish
- Ollalla’s Titi
- Ocellate Soapfish
- Olympic Torrent Salamander
- Oliver’s Warty Pig
- Ouachita Dusky Salamander
- Ota’s Wolf Snake
- Oaxacan Patchnose Snake
- Obi Woodcock
- Oriental Hobby
The Oddballs: Peculiar Animals that Start with the Letter ‘O’
Their appearances and habits may seem incomprehensible, but you will definitely be engaged in learning about these odd animals.
- Orb Weaver
- Old World Porcupine
- Owlet Moth
- Otter Civet
- Olive Colobus
- Orange Leaf-nosed Bat
- Owl-faced Monkey
- Orchid Mantis
- Ornate Spiny Lizard
- Oak Toad
- Orange-bellied Frog
- Oriental Bell Toad
- Orange Ibis
- Orange Roughy
Overloaded with Cuteness: Attractive Animals that Start with the Letter ‘O’
Satisfy your craving for something cute by these animals oozing with cuteness.
- Old World Harvest Mouse
- Orange-tip Butterfly
- Old World Flycatcher
- Oriole Finch
- Ojos Azules
- Omilteme Cottontail
- Oldfield Mouse
- Olive-backed Sunbird
- Occidental Gerbil
- Oasis Hummingbird
- Osgood’s Leaf-eared Mouse
Small but Terrific: Tiny Creatures that Start with the Letter ‘O’
These little beings have charms, skills, and strength that will astound you no matter how small they are.
- Ord’s Kangaroo Rat
- Ornate Shrew
- Obbes’ Catfish
- Orange Beetle
- Orange Sulfur Butterfly
- Orange Ladybug
- Ornamental Snake
- Ornate Hawk-eagle
- Oregon Spotted Frog
- Olive-backed pocket mouse
- Oriental Reed Warbler
- Orange-thighed Frog
Oversized Creatures: 15 Large Animals that Start with the Letter ‘O’
Check out these massive creatures that will shake the lands, waters, and air on earth with their size.
- One-spot Moray Eel
- Old English Mastiff
- Orca (Killer Whale)
- Oceanic Whitetip Shark
- Orinoco River Dolphin
- Oriental Honey Buzzard
- Ongole Cattle
- Oriental White Stork
- Ocean Sunfish
- Olive Ridley Turtle
Over-the-top Charms: Adorable Animals that Start with the Letter ‘O’
Get stunned by these animals and their inordinate appeal that will make you squeal in joy.
- Old English Sheepdog
- Oriental Pipit
- Opossum Rat
- Oriental Scops Owl
- Okinawa Rail
- Oriental Bicolour
- Oriental Longhair
- Oriental Shorthair
- Ogilby’s Duiker
- Ogilvie mountain Collared Lemming
- Olive Bulbul