92 Animals that Start with O: List and Fun Facts

Ever wonder what unique creatures are hiding just beyond the letter O?

Those moments when you think you know animals, but then something completely unexpected comes along? The animal kingdom is packed with surprises that most of us never see.

From the eight-armed wonder of the ocean to the mysterious olm living in underground caves, the O-named animals are anything but ordinary.

Imagine a world where fish can glow, birds dive from incredible heights, and tiny mammals live lives we can barely imagine.

These aren’t just random animals. They’re nature’s masterpieces—each with a story that’s more incredible than the last.

Ready to explore a world of extraordinary creatures that prove just how wild and wonderful our planet can be? Let’s get into the wonderful universe of O-named animals together.

Common Animals Names Starting with “O”

1. Octopus

The octopus is a fascinating and highly intelligent marine animal with eight flexible arms. Each arm is equipped with numerous suckers, enabling the octopus to grasp objects and perform complex tasks.

Known for its exceptional ability to change color and texture, the octopus can camouflage seamlessly with its environment to avoid predators. It is also an excellent hunter, capturing prey with precision and skill.

Origin: Found in oceans worldwide, particularly in temperate and tropical regions.

Scientific Name: Octopus vulgaris

Habitat: Coral reefs, Ocean floor, Caves and crevices, Deep-sea environments

Fun Facts:

• Octopuses have three hearts and blue blood.
• Some species can squeeze through openings as small as a coin.
• They are known to use tools, such as coconut shells, for shelter.

2. Ocelot

The ocelot is a wild cat known for its beautiful coat patterned with rosettes and stripes. These nocturnal predators are agile and stealthy hunters, capable of climbing trees and swimming.

Ocelots feed on a variety of prey, including small mammals, birds, and reptiles. Their elusive nature and keen senses make them expert hunters in the wild.

Origin: Native to Central and South America.

Scientific Name: Leopardus pardalis

Habitat: Tropical forests, Grasslands, Rainforests

Fun Facts:

• Ocelots are excellent climbers and swimmers.
• They communicate with distinctive vocalizations like growls, roars, and meows.
• Ocelots have been bred in captivity for their beautiful fur, though they remain wild animals.

3. Ostrich

The ostrich is the largest living bird, known for its long neck, legs, and inability to fly. Despite its size, it is an incredibly fast runner, reaching speeds of up to 60 miles per hour.

Ostriches are omnivores, feeding on plants, seeds, and small insects. Their large eggs are the biggest among all land animals.

Origin: Native to Africa.

Scientific Name: Struthio camelus

Habitat: Savannas, Deserts, Open woodlands

Fun Facts:

• Ostriches can run faster than any other bird.
• They lay the largest eggs of any living land animal.
• An ostrich’s eyes are larger than its brain.

4. Otter

Otters are playful aquatic mammals known for their curious nature and dexterous skills. They are skilled hunters, using tools to crack open shellfish and other hard foods.

With their thick fur, otters stay warm in cold water, often floating on their backs to eat or rest. Their playful antics in the water are a delight to observe.

Origin: Found in oceans and freshwater bodies worldwide.

Scientific Name: Lutra lutra (European Otter), Enhydra lutris (Sea Otter)

Habitat: Rivers, Lakes, Coastal waters, Wetlands

Fun Facts:

• Otters use rocks as tools to crack open shells.
• They hold hands while sleeping to prevent drifting apart.
• Otters have a high metabolism and must eat 20-30% of their body weight daily.

5. Owl

Owls are nocturnal birds of prey, easily recognizable by their large eyes, round faces, and silent flight. They have exceptional hearing and are skilled hunters, using their sharp talons to catch small mammals, birds, and insects.

Owls can rotate their heads almost 270 degrees to spot prey in the dark.

Origin: Found worldwide, except for Antarctica.

Scientific Name: Strigidae (family)

Habitat: Forests, Grasslands, Deserts, Woodlands

Fun Facts:

• Owls can rotate their heads up to 270 degrees.
• They have a specialized facial disc that helps them capture sound.
• Some species of owls can fly silently due to special feather adaptations.

6. Orangutan

Orangutans are large primates with long, reddish-brown hair and a gentle demeanor. Native to the rainforests of Southeast Asia, they spend most of their lives in trees, where they build nests and forage for fruit.

Orangutans are highly intelligent, known for using tools and exhibiting problem-solving abilities.

Origin: Southeast Asia (Borneo and Sumatra).

Scientific Name: Pongo pygmaeus (Bornean), Pongo abelii (Sumatran)

Habitat: Tropical rainforests, Forests

Fun Facts:

• Orangutans share about 97% of their DNA with humans.
• They are the largest tree-dwelling mammal.
• Orangutans are critically endangered due to habitat loss and poaching.

7. Opossum

Opossums are marsupials found primarily in North and Central America. Known for their unique defense mechanism, they “play dead” when threatened, a behavior called “playing possum.”

They are nocturnal omnivores, feeding on a wide variety of food, from fruits and insects to small animals.

Origin: North and Central America.

Scientific Name: Didelphis virginiana

Habitat: Woodlands, Forests, Urban areas

Fun Facts:

• Opossums have prehensile tails, which they use to grasp branches.
• They have a resistance to snake venom.
• Opossums can carry over 13 different parasites in their bodies.

8. Okapi

The okapi is a unique herbivorous mammal closely related to the giraffe, though it resembles a horse with zebra-like markings on its legs.

Native to the rainforests of Central Africa, it is a solitary, elusive animal that is often hard to spot due to its camouflage. Okapis primarily feed on leaves, fruits, and fungi.

Origin: Central Africa (mainly the Democratic Republic of the Congo).

Scientific Name: Okapia johnstoni

Habitat: Tropical rainforests

Fun Facts:

• Okapis have a long, prehensile tongue that helps them pull leaves from trees.
• They are related to giraffes, despite their smaller size.
• Okapis are known to have a strong sense of smell.

9. Ox

Oxen are large, strong domesticated animals commonly used as draft animals in agriculture and transport. They are typically castrated male cattle trained for heavy work, such as plowing fields and pulling carts.

Oxen are known for their strength and endurance, making them invaluable in farming and rural areas around the world.

Origin: Domestic, derived from wild ancestors in Europe, Asia, and Africa.

Scientific Name: Bos taurus

Habitat: Farmlands, Grasslands, Rural areas

Fun Facts:

• Oxen can pull heavy loads for hours without tiring.
• They have a gentle and patient nature, making them ideal for work animals.
• Oxen have been used for centuries in farming, with evidence of their use going back over 4,000 years.

10. Oystercatcher

Oystercatchers are coastal birds known for their long, bright orange bills and black-and-white plumage. These birds are skilled at hunting shellfish, using their bills to pry open oysters and other mollusks.

They are often found along sandy shores and rocky coastlines, where they forage for food.

Origin: Coastal regions of Europe, Africa, and the Americas.

Scientific Name: Haematopus ostralegus

Habitat: Coastal shores, Mudflats, Rocky beaches

Fun Facts:

• Oystercatchers can crack open mollusks with their strong beaks.
• They are known to be highly territorial and aggressive towards other birds.
• Oystercatchers have excellent vision, helping them spot prey from great distances.

11. Olive Ridley Turtle

The Olive Ridley turtle is a small species of sea turtle known for its olive-colored shell.

These turtles are primarily found in tropical and subtropical waters, where they are famous for their mass nesting events, called arribada, where thousands of females come ashore to lay eggs.

Origin: Tropical and subtropical oceans worldwide.

Scientific Name: Lepidochelys olivacea

Habitat: Coastal waters, Beaches for nesting

Fun Facts:

• Olive Ridley turtles are the smallest of the sea turtles.
• They engage in mass nesting events, with thousands of turtles coming ashore at the same time.
• These turtles can live up to 50 years in the wild.

12. Onager

The onager is a wild donkey species found in Asia. It has a short, upright mane and a body built for speed, enabling it to outrun predators in its natural habitat.

Onagers are typically solitary animals but are also known to form small herds. They feed on grasses and shrubs in the wild.

Origin: Central Asia, Iran, and parts of the Middle East.

Scientific Name: Equus hemionus

Habitat: Deserts, Grasslands, Rocky regions

Fun Facts:

• Onagers are known for their speed, capable of running at over 40 miles per hour.
• They are very vocal animals, using calls to communicate with each other.
• The onager is critically endangered due to habitat loss and hunting.

13. Ochre Sea Star

The ochre sea star is a marine invertebrate known for its striking appearance with vibrant purple, orange, or red colors. These starfish are carnivorous, feeding primarily on mollusks, such as clams and mussels.

They can regenerate lost limbs and are a common sight in tidal pools and shallow ocean waters.

Origin: Found along the Pacific coast of North America.

Scientific Name: Pisaster ochraceus

Habitat: Rocky shores, Tide pools, Shallow ocean waters

Fun Facts:

• Ochre sea stars can regenerate lost arms.
• They have tube feet that help them pry open shells to access prey.
• The ochre sea star is a keystone species in its ecosystem, maintaining balance by controlling mollusk populations.

14. Old English Sheepdog

The Old English Sheepdog is a large, furry breed with a distinctive shaggy coat. Known for their herding abilities, these dogs are intelligent, loyal, and protective of their families.

Despite their rough appearance, they are often gentle and friendly, making them great companions.

Origin: United Kingdom.

Scientific Name: Canis lupus familiaris (dog family)

Habitat: Homes, Farms, Open fields

Fun Facts:

• Old English Sheepdogs are known for their distinctive “bobtail” (short tail).
• They were originally bred to herd sheep and cattle.
• They are great with children and make excellent family pets.

15. Ocean Sunfish

The ocean sunfish is one of the heaviest bony fish in the world. With a flattened, disc-shaped body and large dorsal and anal fins, it is an unusual-looking fish.

Despite its size, the sunfish is known for its slow swimming and tendency to bask in the sun near the surface of the ocean, often flipping onto its side.

Origin: Found in oceans worldwide, particularly in temperate and tropical waters.

Scientific Name: Mola mola

Habitat: Open ocean, Coastal waters

Fun Facts:

• Ocean sunfish can grow up to 10 feet in length and weigh over 2,000 pounds.
• They are known to breach out of the water, jumping in a vertical position.
• Sunfish feed on jellyfish, which makes up the majority of their diet.

16. Oyster

Oysters are marine bivalve mollusks with rough, irregular shells. Known for their ability to filter water, oysters play an important role in maintaining healthy ecosystems.

They are also prized as a delicacy and are often eaten raw. Some oysters produce pearls, which are highly valued in jewellery making.

Origin: Native to both the Atlantic and Pacific Oceans.

Scientific Name: Ostrea (various species)

Habitat: Shallow coastal waters, Muddy or sandy bottoms

Fun Facts:

• Oysters are filter feeders, filtering up to 50 gallons of water a day.
• Some oysters can live for up to 20 years.
• Oysters can change sex multiple times throughout their life.

17. Oxpecker

The oxpecker is a small bird often seen riding on the backs of large herbivores like buffalo, giraffes, and rhinoceroses.

These birds feed on ticks, dead skin, and parasites found on the animals, which provides a mutual benefit to both the oxpecker and its host.

Origin: Sub-Saharan Africa.

Scientific Name: Buphagus (various species)

Habitat: Savannas, Grasslands, Woodlands

Fun Facts:

• Oxpeckers have a distinctive call that sounds like a high-pitched whistle.
• They are known to sometimes peck at their host animals’ wounds to drink blood, which is not always mutually beneficial.
• Oxpeckers are highly social and live in large flocks.

18. Opah

The opah, also known as the moonfish, is a large, brightly colored fish found in deep ocean waters. It has a round body with silver, red, and orange hues.

The opah is unique among fish for its ability to regulate its body temperature, allowing it to hunt in colder waters than most other fish.

Origin: Found in temperate and tropical oceans worldwide.

Scientific Name: Lampris guttatus

Habitat: Deep ocean waters, Coastal areas

Fun Facts:

• Opahs can swim in both cold and warm water due to their ability to regulate body temperature.
• They have large, round eyes that help them detect prey in dark waters.
• Opahs are sometimes called “moonfish” due to their round, silvery shape.

19. Oriole

Orioles are brightly colored songbirds with striking orange and black plumage, though some species also feature yellow and brown colors.

Known for their beautiful songs, orioles build intricate, hanging nests from twigs and fibers. They are typically found in forests and woodlands, where they feed on fruits, nectar, and insects.

Origin: North and South America, Eurasia, Africa.

Scientific Name: Icterus (New World orioles), Oriolus (Old World orioles)

Habitat: Woodlands, Forests, Urban areas with trees

Fun Facts:

• Orioles are known for their beautiful, complex songs.
• They are among the few bird species that can extract nectar from flowers using their specialized bills.
• Some species of orioles migrate long distances between breeding and wintering grounds.

20. Omura’s Whale

Omura’s whale is a recently discovered species of baleen whale known for its small size and distinct markings on its body.

Unlike other baleen whales, Omura’s whale has a more slender build and is often found in deep ocean waters. Little is known about its behavior, as it remains elusive and rarely seen.

Origin: Primarily found in the Indian and Pacific Oceans.

Scientific Name: Balaenoptera omurai

Habitat: Open ocean, Deep-sea environments

Fun Facts:

• Omura’s whale was only officially recognized as a separate species in 2003.
• They are among the smaller baleen whales, with some growing up to 40 feet long.
• Their unique markings and asymmetrical coloration help distinguish them from other baleen whales.

21. Olingo

The olingo is a small, arboreal mammal native to Central and South America. It belongs to the raccoon family and is closely related to the kinkajou.

Olingos have long, prehensile tails that help them navigate the treetops, where they feed on fruit, nectar, and insects.

Origin: Central and South America (mainly rainforests).

Scientific Name: Bassaricyon gabbii

Habitat: Tropical rainforests, Wooded areas

Fun Facts:

• Olingos are nocturnal and are often seen only at night.
• Their long tail is used for balance as they move through the trees.
• Olingos are closely related to the kinkajou, both having similar behaviors and physical traits.

22. Ornate Box Turtle

The ornate box turtle is a small, land-dwelling turtle known for its beautifully patterned shell. With yellow lines on a dark brown or black background, it is easily recognizable.

These turtles are known for their ability to close their shells completely, offering protection from predators. 

Origin: Native to central United States.

Scientific Name: Terrapene ornata

Habitat: Grasslands, Prairie regions, Open woodlands

Fun Facts:

• The ornate box turtle can completely close its shell for protection.
• It is one of the longest-living species of turtles, with some individuals reaching over 100 years.
• These turtles have a slow metabolism and can survive for weeks without food.

23. Otterhound

The otterhound is a large, strong scent hound known for its distinctive rough coat and long ears. Originally bred to hunt otters, these dogs are excellent swimmers and have an exceptional sense of smell.

Otterhounds are friendly and playful, making them great family pets, although they require plenty of exercise to stay healthy.

Origin: United Kingdom, specifically in England.

Scientific Name: Canis lupus familiaris (dog family)

Habitat: Woodlands, Marshes, Riversides

Fun Facts:

• Otterhounds have an excellent sense of smell and are often used in scent tracking.
• Their rough coat helps protect them from cold, wet environments.
• Otterhounds are known to be very friendly and social dogs.

24. Osprey

The osprey is a large bird of prey known for its striking white head and dark eyes. They are excellent fish hunters, using their strong talons to grab fish from the water while flying.

Ospreys build large nests in tall trees or on man-made structures near water, where they can catch their prey.

Origin: Found on every continent except Antarctica.

Scientific Name: Pandion haliaetus

Habitat: Coastal areas, Rivers, Lakes, Wetlands

Fun Facts:

• Ospreys are sometimes called “fish hawks” due to their diet.
• They have reversible outer toes that allow them to grasp fish securely.
• Ospreys can dive from great heights to catch fish in the water.

25. Olm

The olm is a blind, aquatic salamander native to caves in the Balkans. Known for its pale, almost translucent skin, it spends its entire life in the dark, subterranean waters.

The olm has a unique ability to survive without food for extended periods and is an example of extreme adaptation to cave life.

Origin: Cave systems in the Balkans (Slovenia, Croatia, and surrounding areas).

Scientific Name: Proteus anguinus

Habitat: Cave streams, Underground lakes

Fun Facts:

• Olms can live for up to 100 years.
• They can survive for long periods without food, sometimes fasting for years.
• Olms are also known as “human fish” due to their pale, translucent skin.

26. Onychodus

Onychodus was an extinct genus of predatory fish from the Devonian period. These creatures had a shark-like appearance and were considered to be an important part of the ecosystem in ancient seas.

Fossils show that they had sharp, conical teeth and were efficient hunters.

Origin: Devonian period (around 419 to 359 million years ago).

Scientific Name: Onychodus (genus)

Habitat: Ancient seas

Fun Facts:

• Onychodus was one of the early predators in ancient marine ecosystems.
• Its teeth were conical, designed for grasping and tearing prey.
• Fossilized remains of Onychodus provide important insight into early marine life.

Uncommon Animals that Start with O

27. Olinguito (Bassaricyon neblina) – The smallest raccoon family member, discovered in 2013.
28. Okapi (Okapia johnstoni) – A rare herbivore from Central Africa, related to giraffes.
29. Omphalotus (Omphalotus olearius) – A bioluminescent mushroom that glows in the dark.
30. Osprey (Pandion haliaetus) – A fish-eating bird that dives from great heights.
31. Otocyon (Otocyon megalotis) – The bat-eared fox with large ears for insect detection.
32. Oxyuranus (Oxyuranus spp.) – Venomous snakes, including the world’s most venomous, the inland taipan.
33. Oxpecker (Buphagus spp.) – Birds that eat ticks and parasites off large herbivores.
34. Ovis (Ovis aries) – The genus of domestic sheep, raised for wool and meat.
35. Orb-weaving Spider (Araneidae spp.) – Known for spinning geometric webs to trap prey.
36. Orocopis (Orocopis spp.) – Cicadas recognized for their loud, persistent summer calls.
37. Oribi (Ourebia ourebi) – Small, agile African antelopes that evade predators quickly.
38. Okeratochilus (Okeratochilus spp.) – Freshwater fish found in tropical rivers, popular in aquariums.
39. Orange Roughy (Hoplostethus atlanticus) – Deep-sea fish known for its longevity and slow reproduction.
40. Oxalis (Oxalis spp.) – Plants with clover-like leaves and colorful flowers, also known as wood sorrels.
41. Otterhound (Lutra lutra) – Large scent hounds bred for hunting otters, excellent swimmers.
42. Opisthorchis (Opisthorchis spp.) – Parasitic flatworms causing liver diseases in mammals, including humans.
43. Oxybelis (Oxybelis spp.) – Non-venomous, tree-dwelling vine snakes with slender bodies.
44. Ornate Tree Frog (Hyla ornata) – Brightly colored tree frogs from tropical regions.
45. Osteolaemus (Osteolaemus tetraspis) – Critically endangered West African slender-snouted crocodile.
46. Ozark Hellbender (Cryptobranchus alleganiensis alleganiensis) – Large aquatic salamander from the Ozarks.
47. Oxyrhynchus (Oxyrhynchus spp.) – Extinct fish genus with long, pointed snouts.
48. Obsolete Frog (Rana obsoleta) – Rare, declining frog species due to habitat destruction.
49. Orthoptera (Orthoptera spp.) – Insect order including grasshoppers, crickets, and locusts, known for jumping and calls.
50. Ocellaris Clownfish (Amphiprion ocellaris) – Aquarium fish that forms symbiotic relationships with sea anemones.
51. Oystercatcher (Haematopus ostralegus) – Coastal bird with strong bills to open shellfish.
52. Oakhorn Beetle (Acanthocinus aedilis) – Large woodboring beetle with long antennae, often in oak forests.
53. Oriental Bay Owl (Phodilus badius) – Nocturnal Southeast Asian bird with a heart-shaped face.
54. Opah (Lampris guttatus) – Brightly colored deep-sea fish, known as moonfish.
55. Obese Sea Cucumber (Isostichopus fuscus) – Sea cucumber that inflates its body when threatened.
56. Ornate Spiny Frog (Theloderma ornate) – Tree-dwelling frog with rough, spiny texture for camouflage.
57. Overdrive Beetle (Blapstinus spp.) – Fast-moving ground beetle found in temperate regions.
58. Ostracod (Ostracoda spp.) – Tiny crustaceans with hard, hinged shells, found in marine and freshwater environments.
59. Obadiah’s Caddisfly (Obadiah obadiah) – Rare caddisfly with delicate, translucent wings and aquatic larvae.
60. Ochsner’s Hornbill (Tockus ochsneri) – Brightly colored hornbill from West Africa with a large beak.
61. Onychodactylus (Onychodactylus japonicus) – Japanese aquatic salamander adapted for underwater life.
62. Oceanic Squid (Moroteuthis spp.) – Deep-sea squid known for bioluminescence and cold-water adaptation.
63. Outrigger Crab (Tricorneia spp.) – Small marine crab found clinging to tidal pools on rocky shores.
64. Oriental Fire-bellied Toad (Bombina orientalis) – Brightly colored toad with red-orange belly markings, native to East Asia.
65. Ocean Sunfish (Mola mola) – One of the largest fish, known for its flat, disc-shaped body.
66. Otterfish (Labridae spp.) – Marine fish found in kelp forests, known for playful behavior.
67. Ochotona (Ochotona spp.) – Small mammals, or pikas, living in rocky mountain habitats.
68. Oceanic Crustacean (Decapoda spp.) – Deep-ocean crustaceans, including lobsters and shrimp.
69. Ostrich Fern (Matteuccia struthiopteris) – Fern with feathery, plume-like fronds, native to North America.
70. Onychomys (Onychomys spp.) – Predatory grasshopper mice that hunt insects and small animals.
71. Orbweaving Spider (Araneidae spp.) – Spiders skilled at spinning round, geometric webs.
72. Orokosaurus (Orokosaurus spp.) – Prehistoric reptiles related to modern crocodiles.
73. Orange-breasted Falcon (Falco deiroleucus) – Rare and fast falcon from Central and South America.
74. Outlaw Tuna (Thunnus spp.) – Large, fast swimming tuna found in the open ocean.
75. Oxystoma (Oxystoma spp.) – Territorial fish with distinct coloration in freshwater habitats.
76. Okenia (Okenia spp.) – Brightly colored sea slugs with intricate patterns on their bodies.
77. Oplurus (Oplurus spp.) – Large herbivorous lizards from Madagascar.
78. Ozark River Caddisfly (Agapetus spp.) – Freshwater insect with aquatic larvae in fast-moving streams of the Ozarks.
79. Oropendola (Psarocolius spp.) – Birds known for building elaborate hanging nests in Central and South America.
80. Oscillated Turkey (Meleagris ocellata) – Iridescent feathered turkey from the Yucatán Peninsula.
81. Omura’s Whale (Balaenoptera omurai) – Small, recently discovered baleen whale with distinctive markings.
82. Oldfield Mouse (Peromyscus polionotus) – Small nocturnal rodent found in sandy soils of the southeastern U.S.
83. Onagros (Equus hemionus) – Wild donkeys from Asia known for speed and agility in arid areas.
84. Ornithorynchus (Ornithorhynchus anatinus) – The platypus, a mammal that lays eggs and has a duck-like bill.
85. Olivella (Olivella spp.) – Small, carnivorous sea snails with glossy shells.
86. Oryzomys (Oryzomys spp.) – Rodents, or rice rats, found in North and South America.
87. Oxystomus (Oxystomus spp.) – Beetles with aggressive territorial behavior.
88. Oecomys (Oecomys spp.) – Small rodents from Central and South American rainforests.
89. Oedaleus (Oedaleus spp.) – Grasshoppers found in temperate and arid regions.
90. Oxyblepharum (Oxyblepharum spp.) – Small, colorful lizards native to the Caribbean.
91. Ozark Scorpion (Vaejovis ozarkensis) – Small scorpion from the Ozark Mountains with a potent sting.
92. Oceanic Whitetip Shark (Carcharhinus longimanus) – Open-ocean shark with long white-tipped fins.

Conclusion

From the depths of ocean waters to the highest mountain caves, these O-named animals remind us of something magical: our world is endlessly surprising.

Each creature we’ve explored tells a story of survival, adaptation, and the incredible creativity of nature.

These animals aren’t just random entries in a list. They’re living proof of life’s complexity and wonder. Some are rare, some are common.

Nature doesn’t follow our rules or expectations. It creates, adapts, and thrives in ways we can barely imagine. These O-named animals are more than just interesting facts—they’re a celebration of life’s diversity.

So the next time you think you know everything about the animal kingdom, remember: there’s always another O-mazing creature waiting to surprise you.

Keep exploring. Keep wondering. The world is full of magic.