There are quite a few iconic, and all very interesting, animals that start with letter O for you to browse through but let’s kick things off with some cool facts! There’s a creature here who can’t exactly be put into a box, and you know it as the eerie and fascinating Octopus.

Each of the animals you see below will have their Genus⁽¹⁾ and Species⁽²⁾ listed underneath their classification (Amphibians, Birds, Mammals, etc.) but the Octopus doesn’t fall into any of those. It belongs to the Cephalopoda class, which is where other invertebrate animals are such as Squids. ⁽⁴⁾

Now that we’ve got some scientific stuff out of the way, let’s hear the cool facts. The Octopus truly knows a thing or two (or how about eight!) about multitasking, for their suction cup arms can fend for themselves! While the Octopus’s brain is on one task, one of its arms can be doing something entirely different without consulting the brain. ⁽⁵⁾ Imagine how much we could get done if we had that kind of ability!

Shall we keep the fun rolling? Keep an eye out for Animals that are highlighted and click on them for free coloring pages!

Amphibians that Start with the letter O

There’s a few hopping critters on our ist of amphibians that start with the letter O, but one is quite the curiosity to look at and that is the Olm. This salamander creature can be found European caves as it thrives in this climate and the water. Although their eyes are not reliable for sight and are small, their storage for food and energy is not. The Olm can store up so much within it’s liver and tail that it doesn’t have to move for years without eating. ⁽⁶⁾ How crazy is that?!

• Oak Toad (Anaxyrus quercicus)
• Olm (Proteus anguinus)
• Orange Thighed Tree Frog (Litoria xanthomera)
• Oregon Spotted Frog (Rana pretiosa)
• Oriental Fire-Bellied Toad (Bombina orientalis)
• Ornate Chorus Frog (Pseudacris ornata)
• Ornate Cloud Frog (Aromobates ornatissimus)
• Osorio’s Spiny Reed Frog (Afrixalus osorioi)

Birds that Start with the letter O

We can’t approach a list of birds that start with the letter O and not bring forth the legendary Ostrich! We all know that this is winged fella is the largest bird in the world and their eggs are no joke either, but did you know there is a big misconception about them?

Rather its comics or cartoons you may have seen some kind of joke about an Ostrich sticking its head in the sand, and this is where the misconception lies. Ostriches do in fact bring their heads low to the ground while using their body color and feathers to attempt to blend into their surroundings, but their head doesn’t physically get buried into the sand. ⁽⁷⁾ Now you know some fun piece of Ostrich trivia, you’ll be the life of the party!

• Oak Titmouse (Baeolophus inornatus)
• Oasis Hummingbird (Rhodopis vesper)
• Oaxaca Hummingbird (Eupherusa cyanophrys)
• Oaxaca Sparrow (Aimophila notosticta)
• Obbia Lark (Spizocorys obbiensis)
• Oberholser’s Fruit Dove (Ptilinopus gularis)
• Oberländer’s Ground Thrush (Zoothera oberlaenderi)
• Obi Paradise-crow (Lycocorax obiensis)
• Obscure Berrypecker (Melanocharis arfakiana)
• Obscure Honeyeater (Lichenostomus obscurus)
• Oceanic Flycatcher (Myiagra oceanica)
• Ochre Oriole (Icterus spurius)
• Oilbird (Steatornis caripensis)
• Okarito Kiwi (Apteryx rowi)
• Okinawa Rail (Gallirallus okinawae)
• Okinawa Woodpecker (Dendrocopos noguchii)
• Oleaginous Hemispingus (Hemispingus frontalis)
• Olivaceous Elaenia (Elaenia mesoleuca)
• Olivaceous Flatbill (Rhynchocyclus olivaceus)
• Olivaceous Flycatcher (Muscicapa olivascens)
• Olivaceous Greenlet (Hylophilus olivaceus)
• Olivaceous Piculet (Picumnus olivaceus)
• Olivaceous Piha (Snowornis cryptolophus)
• Olivaceous Siskin (Spinus olivacea)
• Olivaceous Thornbill (Chalcostigma olivaceum)
• Olivaceous Woodcreeper (Sittasomus griseicapillus)
• Olive Bee-eater (Merops superciliosus)
• Olive-backed Pipit (Anthus hodgsoni)
• Olive-sided Flycatcher (Contopus cooperi)
• Olomaʻo (Myadestes lanaiensis)
• Olrog’s Cinclodes (Cinclodes olrogi)
• Olrog’s Gull (Larus atlanticus)
• Olson’s Petrel (Bulweria bifax)
• Omani Owl (Strix butleri)
• ʻŌmaʻo (Myadestes obscurus)
• One-colored Becard (Pachyramphus homochrous)
• Opal-crowned Manakin (Lepidothrix iris)
• Opal-crowned Tanager (Tangara callophrys)
• Opal-rumped Tanager (Tangara velia)
• Opalton Grasswren (Amytornis rowleyi)
• Orange Bullfinch (Pyrrhula aurantiaca)
• Orange Chat (Epthianura aurifrons)
• Orange Fruit Dove (Ptilinopus victor)
• Orange-crowned Warbler (Oreothlypis celata)
• Oriole (Icterus)
• Orchard Oriole (Icterus spurius)
• Oriental Turtle-Dove (Streptopelia orientalis)
• Ornate Hawk-Eagle (Spizaetus ornatus)
• Ortolan Bunting (Emberiza hortulana)
• Osprey (Pandion haliastus)
• Ostrich (Struthio camelus)
• Oustalet’s Sunbird (Nectarinia oustaleti)
• Oustalet’s Tyrannulet (Phylloscartes oustaleti)
• Outcrop Sabrewing (Campylopterus calcirupicola)
• Ouvea Parakeet (Eunymphicus uvaeensis)
• Ouzel (Turdus torquatus)
• Ovambo Sparrowhawk (Accipiter ovampensis)
• Ovenbird (Seiurus aurocapilla)
• Owston’s Tit (Sittiparus owstoni)
• Oxpecker (Buphagus)

Dogs that Start with the letter O

You might recognize this adorable dog, amongst our dogs that start with the letter O list, from Disney classics such as The Little Mermaid and Shaggy Dog; it’s the Old English Sheepdog!

You may think with a name like Old English Sheepdog that this breed helped herd sheep, but they actually made sure that sheep and cattle made it to the market! With this big dog’s coat it could easily disguise itself amongst the sheep. ⁽⁸⁾ Talk about a dog in sheep’s clothing!

• Old Croatian Sighthound
• Old Danish Pointer
• Old English Sheepdog
• Old English Terrier
• Olde English Bulldogge
• Otterhound

Fish that Start with the letter O

Have you ever named your pet fish? Well, how about this, have you ever owned a fish that had a first name for it’s species? Meet the South American native Oscar fish, a pretty fishy that is becoming quite desirable in the aquarium community!

These stunning fish would make the eyes of any aquarium enthusiasts sparkle, but the other fish in the tank may not be as thrilled. The Oscar fish is known to be territorial and let’s just say not too nice to its roommates. In other words, this is more of a solo fish! Oscar fish can live up to 20 years and they come in a verity of beautiful colors. ⁽⁹⁾

• Oarfish (Regalecidae)
• Ocean Perch (Sebastes alutus)
• Ocean Sunfish (Mola mola)
• Oceanic Whitetip Shark (Carcharhinus longimanus)
• Ocellaris Clownfish (Amphiprion ocellaris)
• Oilfish (Ruvettus pretiosus)
• Old Wife (Enoplosus armatus)
• Old World Knifefish (Chitala ornata)
• Olive Flounder (Paralichthys olivaceus)
• Opah (Lampris)
• Opaleye (Girella nigricans)
• Orange Roughy (Hoplostethus atlanticus)
• Orange-spine Unicorn Fish (Naso lituratus)
• Orange-striped Triggerfish (Balistapus undulatus)
• Orbicular Batfish (Platax orbicularis)
• Orbicular Velvetfish (Caracanthidae)
• Oregon Chub (Oregonichthys crameri)
• Orfe (Leuciscus idus)
• Oriental Loach (Misgurnus anguillicaudatus)
• Oscar (Astronotus ocellatus)
• Owens Pupfish (Cyprinodon radiosus)

Insects & Spiders that Start with the letter O

Spiders are lumped into the critters of nightmares, but we’ve got to give these particular spiders some praise for their incredible features! The Orb Weaver Spiders can grow to be quite large, and their webs are top notch. So much, in fact, that a fisherman could use the Orb Weavers web for a fishing net! ⁽¹⁰⁾ You wouldn’t want to get caught in that sticky web!

• Ogre-faced Spider (Deinopidae)
• Orange Beetle (Harmonia axyridis)
• Orange Blister Beetle (Meloidae)
• Orange Sulfur Butterfly (Colias eurytheme)
• Orb Weaver Spiders (Araneidae)
• Orchid Mantis (Hymenopus coronatus)
• Owl Butterfly (Caligo)
• Owlfly (Ascalaphidae)

Mammals that Start with the letter O

From Orangutans to Opossums there’s quite the range of critters for mammals that start with the letter O, and one cuddly looking animal we can’t help but bring to the spotlight; the otter!

These smart and adorable creatures can be found playing and floating around almost everywhere with the exception of Antarctica and Australia. Of course their little faces are too cute, but we have another fact that will pull your heartstrings. Often when Otters are sleeping on their backs in the water, they will hook paws with another Otter so they don’t float away. ⁽¹¹⁾ Essentially holding hands, how adorable is that!

• Ocelot (Leopardus pardalis)
• Okapi (Okapia johnstoni)
• Olingo (Bassaricyon)
• Omilteme Cottontail (Sylvilagus insonus)
• Opossum (Didelphidae)
• Orange-spined Hairy Dwarf Porcupine (Sphiggurus villosus)
• Orangutan (Pongo)
• Orca (Orcinus orca)
• Ord’s Kangaroo Rat (Dipodomys ordii)
• Ornate Shrew (Sorex ornatus)
• Otter (Lutrinae)
• Owl-faced Monkey (Cercopithecus hamlyni)

Reptiles that Start with the letter O

Looks like we’ve got a heavy sleeper on our list of reptiles that start with the letter O! The majestic Olive Ridley Sea Turtle is of course a creature of the sea, hence it’s given name, so by nature we can assume that they spend quite a lot of their time under water. But did you know that this beautiful seas turtle can sleep up to two whole hours under water before it swims up to the surface? ⁽¹²⁾ That’s one dedicated sleepy head!

• Olive Ridley Sea Turtle (Lepidochelys olivacea)
• Orange-throated Whiptail (Aspidoscelis hyperythra)
• Ornate Tree Lizard (Urosaurus ornatus)
• Osage Copperhead (Agkistrodon contortrix phaeogaster)

Oh my is there tons to absorb from all those neat facts on animals that start with letter O! Give your brain a dazzling break with these free and fun Animal Coloring Sheets. These pages are ready to be printed, colored, and enjoyed!