Cold-Blooded Animals: 10 Animals That Can’t Regulate Their Own Body Temperature

Written by Brandi Allred
Published: September 17, 2022
Image Credit Martin Mecnarowski/Shutterstock.com
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The Earth is home to a boundless array of plants and animals. Among animals, there are two distinct classes; warm-blooded and cold-blooded. Cold-blooded animals are those that cannot use internal bodily processes to warm or cool their bodies. Also known as ectotherms, these animals include amphibians, reptiles, and fish. Many cold-blooded animals, like fish, simply don’t need warm blood to survive. Others, like most reptiles, rely on the heat of the sun to bring their bodies up to temperature.

Let’s discover some of the most fascinating cold-blooded animals!

1. Rhinoceros Viper

River Jack Snake or Rhinoceros Viper
Rhinoceros vipers are among the most beautiful cold-blooded animals on Earth.

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Rhinoceros vipers are among the most beautiful cold-blooded animals on Earth. These little-known snakes are closely related to Gaboon vipers, though they grow to only about four feet long and have much more slender bodies. Rhinoceros vipers are highly venomous but rarely bite humans. They have horn-like scales on the tips of their noses (hence their name) and intricately patterned bodies. These snakes exhibit a wide variety of colors, including black, brown, pink, blue, yellow, and tan. 

2. Tiger Shark

Largest Tiger Shark - tiger shark's distinctive feature
The tiger shark gets its name from the vertical lines that run along the side of its body.

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Perhaps one of the most famous of all cold-blooded animals, the tiger shark is one of the deadliest hunters in the ocean. Tiger sharks grow up to 18 feet long and eat everything from small fish and cephalopods to carrion and garbage. Tiger sharks, along with bull sharks and great whites, are responsible for the majority of attacks on humans. These sharks live in all the tropical and subtropical oceans of the world. 

3. Cane Toad

close up of cane toad looking at camera
Cane toads are among the largest toads on Earth.

Ondrej Prosicky/Shutterstock.com

Cane toads are among the largest toads on Earth. These cold-blooded animals are native to South and Central America. But, because they’re so good at surviving, they’ve actually become problematic invasive species in Australia, Oceania, and the Caribbean. Cane toads grow up to nine inches long and can eat everything from fish and frogs to mice and other toads. They’re typically light to dark brown in appearance, with sturdy forelegs and long back legs that enable them to leap several feet when hunting. 

4. Tiger Salamander

Barred Tiger Salamander in Arizona
Tiger salamanders have snake-like bodies with short, thick heads and legs.

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One of the most beautiful amphibians on the planet, the tiger salamander grows up to eight inches long. Tiger salamanders have snake-like bodies with short, thick heads and legs. Their most distinctive feature is their coloring; tiger salamanders are black to brown, with thick yellow stripes covering their entire body. These cold-blooded animals live throughout much of the United States, where they spend a great deal of time underground in burrows. Despite their small size and harmless appearance, tiger salamanders are obligate carnivores. They primarily eat earthworms, slugs, insects, tiny crustaceans, and snails.

5. White Sturgeon

White Sturgeon
White sturgeons are North America’s biggest freshwater fish.

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The white sturgeon is one of the largest, most magnificent freshwater fish on the planet. White sturgeons are North America’s biggest fish; they grow up to 1,500 pounds. With shark-like fins and heavy, armored heads, white sturgeon look like relics of prehistory. They live in the fresh waters of the Pacific Coast from Alaska to California. These fish are carnivorous; as they grow, they eat increasingly larger fish, like shad and herring. 

6. Deep-sea Anglerfish

Animals that use mimicry – Anglerfish
Deep-sea anglerfish have gigantic mouths filled with needle-like teeth.

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These cold-blooded animals just might be the stuff of nightmares. Deep-sea anglerfish have gigantic mouths filled with needle-like teeth. In addition to their teeth, they have a phosphorescent (glowing) antenna sticking straight out of their foreheads. This antenna draws unfortunate fish to the anglerfish’s mouth; by the time they realize what’s happening, it’s too late. Deep-sea anglerfish grow up to four feet long; at least, the females do. Males are tiny and spend most of their lives physically attached to a female, taking nourishment from her and providing her with a ready source of sperm in exchange.

7. King Cobra

What Eats Snakes
The king cobra is the longest venomous snake in the world.

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The king cobra is the longest venomous snake in the world. King cobras aren’t as heavy as pythons or anacondas, but what they lack in muscle, they make up for in venom. King cobras possess highly toxic venom, which they can spit at would-be attackers. These snakes are native to India, Southeast Asia, and Indonesia, where they live in tropical rainforests. Like all cobras, they can splay the ribs that make up their necks to create the famous cobra ‘hood.’

8. Blue Poison Dart Frog

Most Colorful Animals: Blue Dart Frog
Blue poison dart frogs are bright blue with black spots, and they’re extremely poisonous.

Natalia Kuzmina/Shutterstock.com

Blue poison dart frogs are among the prettiest cold-blooded animals on Earth. These tiny frogs measure just 1-1.5 inches long and come from Surinam, South America. They’re bright blue with black spots, and they’re extremely poisonous. Poison dart frogs don’t inject venom; instead, the food they eat makes their bodies poisonous to eat or touch. In the wild, they eat mainly ants, though most captive blue poison dart frogs eat fruit flies and crickets.

9. Nile Crocodile

Nile crocodiles are the largest crocodilians on Earth.

David Havel/Shutterstock.com

Nile crocodiles are the largest crocodilians on Earth, and they’re some of the largest cold-blooded animals in the world. Adults grow up to 15 feet long and may weigh over 2,000 pounds. Nile crocodiles are apex predators at the top of the food chain; they eat small to medium-sized mammals, reptiles, fish, and birds. They’re native to much of Africa, as well as the west coast of Madagascar. These reptiles spend much of their time in the water, lying in ambush for prey.

10. Komodo Dragon

Are Komodo dragons poisonous or dangerous
Komodo dragons are famous for their huge size and their bacteria-infested bite.

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These cold-blooded animals are famous both for their huge size and their bacteria-infested bite. Komodo dragons are found only on five Indonesian islands; they’re currently listed as Endangered. Males grow up to 10 feet long and weigh up to 300 pounds. These terrestrial reptiles can run very fast when chasing prey, like Timor deer, wild boar, fish, snakes, and water buffalo. Komodo dragons are typically yellow-brown, with long bodies and smooth heads. They have large gums, which obscure the deadly, needle-sharp teeth lining their mouths.

Up Next:

Huge Nile crocodile, Crocodylus niloticus, running from beach into water. Kariba Lake, Zimbabwe.
Huge Nile crocodile, Crocodylus niloticus, running from beach into water. Kariba Lake, Zimbabwe.
Martin Mecnarowski/Shutterstock.com
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About the Author

Brandi is a professional writer by day and a fiction writer by night. Her nonfiction work focuses on animals, nature, and conservation. She holds degrees in English and Anthropology, and spends her free time writing horror, scifi, and fantasy stories.

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