There’s a huge number of animals in the world for your students to discover, so we’ve narrowed the list down to animals that start with the letter “O”. I’m sure your kids have heard of the common ones like octopus and orangutan, but do they know the onager or the oryx? This list of quirky animals will surely fascinate your learners! From blind salamanders like the olm that can live to be 100 years, to the oceanic whitetip, the most endangered shark species- your kids will learn endless facts about all these creatures. So jump into this thorough list of animals that start with “O” that we’ve made for your curious students!
1. Oak Toad
The oak toad is the smallest in North America; it only reaches up to 33 millimeters! This toad species is on the verge of extinction and is highly threatened by habitat loss.
Learn More: Virginia Herpetological Society
2. Oarfish
The oarfish is a giant fish that is the world’s largest bony fish. It can grow up to 5.5 kg and weigh a whopping 272 kilograms! Although they are extremely large, they are not dangerous and are often eaten if caught. They are also known to predict earthquakes, demonstrating their predictions by washing up on the shore.
Learn More: National Geographic
3. Ocelot
The ocelot looks very similar to other big cats, such as the cheetah and leopard. However, it has many differences. The ocelot is found in the United States, Mexico, as well as Central and South America. This nocturnal mammal is also known as the painted leopard but is generally very small- just a bit bigger than the average house cat.
Learn More: National Geographic
4. Octopus
Octopi have eight tentacles and are extremely intelligent! They have three hearts, but their tentacles have a mind of their own. If you cut off an arm, it will react even though it is not connected to the rest of the body. They also have blue blood and are incredibly flexible and can maneuver through tiny spaces. They also make for a great snack!
Learn More: Smithsonian Magazine
5. Oilbird
Oilbirds are native to South America. They are nocturnal and feed off of various fruits and nuts. They are similar to bats in that they use echolocation to navigate through the night and find their way back to their nests. Their chirps are also unable to be heard by humans!
Learn More: Britannica
6. Okapi
Okapi lives in the rainforests of Congo. These endangered animals are on the verge of being extinct due to habitat loss and human environmental impacts. They are the only relative of a giraffe but are considered to look like a mix of deer and zebras.
Learn More: National Geographic
7. Olive Ridley Sea Turtle
The Oliver Ridley sea turtle is an endangered species that is being rehabilitated and protected by the Endangered Species Act. Their shell has an olive green hue, and they lay their eggs in deep holes in the sand of beaches. Mother sea turtles never see their babies, as they leave once they lay their eggs in the sand and the babies navigate their way to the ocean once hatched.
Learn More: NWF
8. Olm
Olms are amphibians that are classified as salamanders. They are most often found in caves across Europe, but are entirely aquatic and spend most of their time underwater or underground. Olms lack the sense of sight and navigate their surroundings through the use of ultrasonic hearing, smell, and electrosensitivity.
Learn More: Britannica
9. Onager
The onager is a herbivore native to Iran and other parts of Asia. They are also known as the Persian Zebra. They look similar to donkeys but are distinguishable by their sandy coat and brown dorsal stripe. They are often found in mountain steppes or desert-like areas around Saudi Arabia but can be found in places far North, such as Russia, or far East, like Mongolia.
Learn More: Smithsonian National Zoo
10. Opaleye Fish
Opaleye fish are similar to many other fish, but their distinct eyes classify them. Their eyes are big and have a blue-green color, but the rest of their body has a dark olive-green coloring. They are often found in shallow, rocky areas and are caught by local fishermen to be cooked and eaten!
Learn More: Pier Fishing
11. Openbill Stork
The open-bill stork has glossy black wings and a tail that appears to be purple or green. They can only grow to be around 83 cm tall and are coming close to becoming endangered as their population decreases. They live in wetland habitats and are often found in flood fields in Asia.
Learn More: Animalia
12. Opossum
Opossums are omnivores that eat many different plants and animals; most of the time feeding on dead animals and plants. They are great for farmers as they kill tills and are the only marsupial in North America! Opossums play dead when they are scared and only live up to 2 years.
Learn More: National Geographic
13. Orangutan
Orangutans are a type of ape that sleep and live in large trees. These mammals climb up high and build nests; making them the only mammals that live off of the ground! They have extremely large arms and often eat with their feet! They can be found in tropical rainforests, but are facing a crisis of deforestation- putting them on the endangered species list.
Learn More: World Wildlife Organization
14. Orb Weaver
The orb weaver is a nocturnal arachnid that lives in warmer parts of the world. They can be identified by their bright color, large abdomen, and incredibly large webs that can reach up to 1 meter wide. These spiders are not aggressive so there is no need to be afraid of a spider bite if you spot one.
Learn More: Wildlife Heritage
15. Orca
Orcas look like a type of whale, but they are actually part of the dolphin family. Another common name for the orca is the killer whale. They are extremely intelligent and can live to be 80 years old. These dolphins are the world’s strongest predators and can be recognized by their black bodies and white eyes. They hunt animals such as seals, penguins, squid, and other marine animals.
Learn More: National Geographic
16. Oribi
Oribis are found in Africa. They have many predators, including eagles, wild dogs, hyenas, and lions. These herbivores are threatened by habitat destruction due to human populations and expansion.
Learn More: Britannica
17. Oriental Cuckoo
The Oriental Cuckoo can be found in the Himalayan mountains throughout China, Korea, and Japan. They also are native to New Zealand. Their shape resembles a falcon, but they are quite small. They have smooth wings and a long dark grey tail.
Learn More: NZ Birds Online
18. Oriole
Orioles are beautifully bright orange birds common to North America. They migrate in the Winter to survive and are quite easy to identify in your backyard or the open woodlands. They are attracted to feeders with nectar and fruits.
Learn More: EBird
19. Ornate Chorus Frog
Ornate chorus frogs are relatively small frogs with extremely colorful coats. They can be gray, green, and reddish brown, which a black stripe across their eyes. These frogs are found across wetlands in North America, such as the South Carolina Coastal Plain. These amphibians breed in shallow bodies of water and live near open grassy areas with water.
Learn More: Savannah River Ecology Laboratory
20. Oryx
The oryx is an antelope found only in Africa and the Middle East. They have long horns and grey bodies that make them easy to identify. However, these hooved mammals are severely endangered and only live in their native habitat.
Learn More: African Wildlife Foundation
21. Osprey
The Osprey is often known as a sea hawk because they feed off of fish. Ospreys live on every continent with the exception of Antarctica. They have a wingspan that can reach up to 6 feet, and they grow to be around 23 inches long.
Learn More: Scottish Wildlife Trust
22. Ostracod
Ostracods are marine animals that produce bioluminescence. They are one of the oldest species in the world, even older than oysters in which they have been found in history for over 500 million years. Ostracods are omnivores, but most often eat algae and dead plants or animals.
Learn More: Lake Biwa Museum
23. Ostrich
Ostriches are giant birds that can run, but can’t fly! They are the fasted birds in the world that can run up to 43 mph. They are found in the savannas of Africa and in many zoos across the world. They eat mostly plants but sometimes crave small insects and reptiles.
Learn More: Smithsonian National Zoo
24. Otter
Otters are marine animals that lack a layer of blubber. They have thousands of water-resistant hair follicles that keep them warm while they are in the water. There are over 13 species of otter in the world, including the giant otter and the giant river otter. 90% of them live in Alaska!
Learn More: U.S. Department of the Interior
25. Outstalet’s Chameleon
Chameleons are interesting animals as they can change their color to camouflage their surroundings or even show their mood! The outstalet’s chameleon is the world’s largest chameleon and can grow up to 2 feet in length. They are native to Madagascar but can be found in various other parts of the world.
Learn More: Reptiles Magazine
26. Oxen
Oxen are also known as male bulls. They have been domesticated and are used as mules for farm work. They are extremely strong animals and have large horns. You can find oxen in all countries except for South America and Australia.
Learn More: Britannica
27. Oxford Sheep
Oxford sheep are often killed and used for creating fleece. The rams weigh around 300 pounds, and their ewes average about 200 pounds. They are native to the United Kindom in Oxford Country and can be found among farms and grasslands.
Learn More: The Livestock Conservancy
28. Oxpecker
Oxpeckers do exactly what their name says; they peck the bugs and parasites off of oxen, zebra, and other mammals. They can be identified by their big, round yellow eyes and bright red beak. They are most commonly found in Africa in the savannah or grasslands where larger mammals are found.
Learn More: Hluhluwe
29. Oyster
Oysters are one of the oldest animals on the planet. They have been around for over 14 million years! They have gills similar to fish, but instead of using them for breathing, they use them for eating algae and plants! They are also able to change their sex depending on their environment; meaning one could start as a male and transition into a female!
Learn More: A-Z Animals
30. Oyster Catcher
Oystercatchers live near the ocean and are black and white wading birds with long orange bills. They only eat shellfish–especially oysters! They are found in temperate and tropical parts of the world and prefer to walk rather than fly.
Learn More: Britannica
31. Olive Sea Snake
The olive sea snake is a fascinating animal living in the tropical waters of Australia. These venomous predators spend their whole lives at sea hunting fish and crustaceans among the coral reefs. Watch out if you go scuba diving; these giants can grow up to 6.5 feet!
Learn More: Oceana
32. Ornate Box Turtle
The ornate box turtle has a fitting name; its beautiful shell is decorated with bright yellow lines against a brown base. Their range stretches from the eastern to midwestern parts of the United States. These guys are omnivorous animals, meaning that they’ll eat anything from slugs to salamanders to flowers.
Learn More: Racine Zoo
33. Olympic Marmot
Olympic marmots are rare creatures found only in the alpine meadows of the Olympic Peninsula in Washington. These social animals form groups consisting of a male, several females, and their young. If they discover you hiking in their territory, you’ll hear them whistling to one another- warning each other that intruders are coming!
Learn More: National Park Service
34. Ornate Bichir
The ornate bichir, a spotted, slender fish, is long like an eel, which means that fish owners need a large tank to keep these exotic animals happy! Their natural habitat is found in the rivers and lakes of Central Africa, where they hunt for invertebrates at night.
Learn More: Aquadiction
35. Ochre-breasted antpitta
The ochre-breasted antpitta is a tiny and brightly colored bird species that lives throughout Central America and the northwestern region of South America. These small creatures often perch on branches close to the ground and can be seen swaying from side to side while at rest.
Learn More: eBird
36. Olive Python
The olive python is named for its coloring; these snakes have an unusually large number of green scales and a white stomach. They are one of the continent’s largest species of snake, growing up to 16 feet long! Watch out for them in the wild- they’re often found curled up in logs and dark caves; it’s not the surprise encounter you want!
Learn More: Perth Zoo
37. Owl
While over 250 species of owls inhabit the earth, their diverse members actually have quite a lot in common. These birds of prey tend to be nocturnal, have deep, far-reaching calls, and are skilled hunters. Most of them are also solitary animals who roost alone, outside of breeding season.
Learn More: Owl Research Institute
38. Oldfield Mouse
The oldfield mouse is also known as the beach mouse because they make their home along coastal areas. These mice dig complex burrows underground, where they store seasonal seeds to keep them fed through the year. They, themselves, are food for many small predators too, such as foxes and skunks.
Learn More: Outdoor Alabama
39. Olive Baboon
The olive baboon is a powerful, sometimes ferocious monkey living throughout the African savanna and its nearby forests. These social animals live in massive troops of up to 100 members with a complex hierarchy. They defend themselves from predators using their giant canines and galloping run, so approach with care!
Learn More: Toronto Zoo
40. Otterhound
Originally bred for hunting otters (hence the name), otterhounds are natural swimmers with shaggy, water-resistant coats. Nowadays, these cute bearded pups make lively pets, best suited to areas with open spaces for them to get plenty of exercise, and are best suited for pet owners with lots of time and patience.
Learn More: Purina
41. Oregon Spotted Frog
The Oregon spotted frog is named for its habitat in the Pacific Northwest with most species being found in, you guessed it, Oregon! This aquatic animal spends almost all of its time lying in wetlands and ponds, patiently waiting for its catch of the day. These guys don’t really like change and are known for being quite unadaptable to changes in their environment.
Learn More: Oregon Wild
42. Oviraptor
The oviraptor was a small, thieving dinosaur that stole eggs from the nests of other species. These creatures once lived in what is now Mongolia, during the Late Cretaceous Period. While this animal may be extinct, it was far too remarkable not to include it in our list of O animals!
Learn More: Natural History Museum
43. Oceanic Whitetip Shark
Oceanic whitetip sharks may not carry the same notorious reputation as some of their cousins, but they’re still massive and ferocious hunters. What’s more, these sharks are found in waters all over the world, and yet they’re one of the most endangered sharks you’ll meet These ocean animals must swim constantly to breathe. How exhausting!
Learn More: Ocean Conservancy
44. Orange-Throated Tanager
For birdwatchers, spotting one of these exotic animals is a rare treat! The orange-throated tanager is an elusive type of bird found only in certain parts of Peru and Ecuador. The tanager plays a key part in maintaining the forests there, as they make vital contributions to seed dispersal.
Learn More: Nature & Culture International
45. Ornate Hawk-Eagle
The ornate hawk-eagle is known for its perky crest, bright yellow eyes, and striped feathers, all of which make its name quite fitting. The hawk-eagle is a bird of prey found throughout Central and South America, where they hunt other birds and mammals amongst the rainforest trees.
Learn More: Peregrine Fund
46. Owl Butterfly
Owl butterflies have distinctive markings resembling the eyes of an owl; it is thought that these eyes ward off predators by sheer confusion! Their caterpillar form is equally as interesting with each having horns and black spikes along its back. These guys love to eat fermented fruits, and they especially love bananas!
Learn More: Natural History Museum
47. Orange-Winged Amazon
The orange-winged Amazon is the largest bird of its kind living throughout the Amazon rainforest of South America. These beautiful birds not only have, as their name suggests, orange wings but also a striking blue-yellow face. They frequently announce their arrival to a communal roost with a loud screech- making them not so easy to ignore!
Learn More: Animalia
48. Ozark Big-Eared Bat
You’ll only be able to see the Ozark big-eared bat at dusk when they emerge from their caves to forage. This particular bat makes its home in Oklahoma and Arkansas, returning each year to a specific cave to give birth to their young and hibernate.
Learn More: U.S. Fish & Wildlife Service
49. Ocean Sunfish
The ocean sunfish, also known as a mola, is a type of bony fish with silvery-gray coloring and a very flat body. These whoppers can weigh up to 5,000 pounds and have a special tail fin called a clavus, which they use to steer as they swim. I’ve never seen anything like it!
Learn More: Monterey Bay Aquarium
50. Olm
Perhaps the most astounding member of this list of animals is the olm; a blind, cave-dwelling, aquatic salamander found in southeastern Europe. These remarkable animals are blind from living in dark caves their whole lives which can be as long as 100 years. Scientists aren’t quite sure how these slender, pale creatures live so long, but they have no natural predators, which certainly helps!
Learn More: National Geographic
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