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20 Examples of Endotherms (With Pictures)

Different types of animals have adaptations that allow them to survive in different types of environments. Endotherms are a category of animals that internally create the heat they need in their body when adjusting to their environment. In contrast, ectotherms depend on external sources and behavioral changes to regulate their body temperatures. Common examples of endotherms are what we call warm-blooded animals, such as mammals. As humans, we are also endotherms!

Let’s learn more about endotherms and explore examples of animals under this category.

What is an Endotherm?

The body temperature of endotherms doesn’t fluctuate with external weather conditions. Meaning, they have the ability to keep themselves warm through metabolic processes. Endotherms can burn energy cells to produce heat and are often referred to as warm-blooded as a result.

The metabolic rate of endotherms will increase when external temperatures are high, so they typically require more food during warmer weather. They also have different methods to prevent overheating.  Additionally, endotherms can be active both during the day and night, as they are not constrained by the temperatures of the day to stay warm or at a stable temperature.

1. Polar Bears

image: Pixabay.com

Scientific name: Ursus maritimus

Polar bears live by sea ice in areas such as the Arctic, Greenland, Alaska, Russia, Canada, and some islands in northern Norway. These apex predators have evolved to stay warm despite their cold surroundings.

They have a layer of fat up to 4 inches thick under their thick fur to insulate them. During the harsh winters of the Arctic, female polar bears also make burrows in snowbanks to shelter their cubs.

2. Penguins

Scientific family: Spheniscidae

Penguins are a type of aquatic bird that cannot fly. They usually live near coasts and oceans on islands or remote areas with few land predators. They are excellent divers and can swim very fast. The Gentoo penguin (Pygoscelis papua) is one of the fastest species, with speeds up to 22.37 miles per hour.

In the cold, these birds keep warm through the blubber under their thick skin and by huddling together. In the heat, they can cool off by raising each individual feather. When they do this, warm air can escape.

3. Orangutans

Scientific genus: Pongo

Orangutans live mostly in Southeast Asia and there are three main species: Bornean, Sumatran, and Tapanuli. They enjoy swinging through the canopies and have long, strong arms that allow them to do so.

These great apes are very smart, can use tools, and can plan ahead. Every night they build a nest for sleeping in around 10 minutes. During the day, they also cover themselves in large leaves to keep cool.

4. Lions

Scientific name: Panthera leo

Although most wild lions live in Africa, there are also a sub-species of lion in western India. The male adult lion’s majestic manes get darker as they age. It is a sign of dominance, attracts females, and protects their heads and neck during fights.

Lions rely on their large meals to help regulate their body temperature, as their body produces heat while their metabolism works. They can eat up to 88 pounds of meat in a single meal – that’s about a quarter of their body weight. Their prey includes baboons, zebras, wildebeest, antelopes and when prey is scarce they may hunt rodents.

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5. Elephants

Scientific genus: Loxodonta and Elephas

Elephants are the largest land animal globally, weighing over 13,000 pounds. They have multiple ways to adapt to the heat of the hot climates they inhabit. These animals rely on the large surface areas of their ears to radiate heat and help them stay cool. They can also flap their ears to increase body heat radiation.

Their thick skin with wrinkles and folds helps them retain more moisture to cool down. They also take regular mud baths to protect themselves from sunburn.

6. Squirrels

Scientific family: Sciuridae

Squirrels are intelligent, acrobatic, and adaptable rodents that have been introduced to many city parks in countries, including the United States. When it comes to temperature regulation, they cool themselves through respiration and the sweat glands between their toes and the bottom of their feet.

These animals will gain extra weight to stay warm during cold months. Different squirrel species also have different methods of staying warm. Ground squirrels will dig burrows, while some tree squirrels will build dens in tree trunks.

7. Kangaroos

Scientific family: Macropodidae

Kangaroos are marsupials native to Australia and live mostly in desert and savanna habitats. These animals have distinctive long tails and powerful hind legs they use to hop around. They are very fast animals and can hop up to 44 miles per hour!

Their reddish fur can reflect the sun’s heat but also provide insulation when it’s cold. These animals will also cool down by licking their arms.

8. Camels

Scientific genus: Camelus

Camels are often found in deserts where the climate can change drastically from extremely hot to cold. They store fat in their humps to use as energy and keep themselves cool in the daytime heat. To stay warm at night, camels rely on their heavy fur.

The camel’s long legs also provide ample space between them and the hot desert sands, so their bodies are cooler. With feet adapted to walking on sand without sinking or slipping and energy stored in their humps, camels can walk long distances without rest or water.

9. Flamingos

Scientific family: Phoenicopteridae

While most flamingos look similar, there are six different species. They have long legs and adults typically grow around 4 to 5 feet tall. They live by lagoons, lakes, or mudflats, where they congregate and prey mostly on shrimp.

The color of their pink feathers comes from the beta-carotene in the foods they eat. When conditions get too cold, you can observe flamingos shivering to produce heat through muscular energy consumption.

10. Bottlenose Dolphins

image: Pixabay.com

Scientific family: Delphinidae

Dolphins may live in the ocean and swim very well, but they are not fish. These animals are warm-blooded mammals that can regulate their body heat in cold waters. Dolphins also have a thick layer of blubber under their skin to keep them warm.

Their tails are called flukes that they use to swim and they use their flippers to steer. These animals are intelligent, playful, and social and travel in groups called pods. They can even surf waves or swim through self-made bubbles.

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11. Gray Whales

pacific gray whale tail | image by Pamela Gunn via Flickr

Scientific name: Eschrichtius robustus

Gray whales mostly live in shallow waters along the coasts of the North Pacific Ocean. However, they sometimes cross deep waters during migration from Alaska to Baja California in the fall to spend the winter months in warmer waters. They travel around 10,000 miles round trip, making them one of the mammals with the longest annual migrations.

Gray whales can grow up to 49 feet in length and up to around 90,000 pounds. These animals have thinly insulated flippers to prevent heat loss and help them regulate their body temperatures.

12. Seals

Scientific family: Phocidae

Seals are semi-aquatic animals that spend time on land and in the sea. They are agile and flexible when swimming in the sea and can waddle using their four flippers on land. Similar to whales, these flippers have a thin layer of insulation to prevent heat loss. They also have a thick layer of blubber to insulate them in icy waters.

There are around 33 species of seals. While you can find them along coastal habitats with cold waters, most of them live in the Antarctic or Arctic waters.

13. Arctic Wolf

Scientific name: Canis lupus arctos

As their name suggests, the Arctic wolf lives mostly in the Arctic regions of Greenland and North America. They are the only wolves with year-round white fur. This color allows them to blend in with the snow in their habitat.

Arctic wolves have long silky coats with thick fur underneath to keep them warm. In the spring, their coat becomes less dense as the weather warms up. These wolves also have smaller muzzles and ears compared to other wolves, so they can retain body heat.

14. Common Voles

image: Pixabay.com

Scientific name: Microtus arvalis

Voles are small rodents that look similar to field mice. Small mammals like these typically don’t have body insulation. Instead, they take advantage of the insulating qualities of their surroundings, such as snow or dirt.

Voles are known for digging burrows and crisscrossing tunnels underground. Since voles don’t hibernate in the winter, they use their underground home to keep them warm and rely on bark and tree roots as food.

15. Atlantic Bluefin Tuna

bluefin tuna

Scientific name: Thunnus thynnus

Although most fish are ectothermic, Bluefin tunas are uniquely warm-bodied predators. They can elevate their core body temperature above the temperature of their surrounding water. Atlantic Bluefin tunas are known for their ability to migrate throughout the Atlantic ocean at speeds up to 55 miles per hour.

Their endothermic nature allows them to migrate from the cold waters of their feeding grounds to the warm waters of their spawning grounds easily. They can also dive vertically into the ocean, despite significant changes in water temperature at different depths.

16. Koalas

Koala in tree

Scientific name: Phascolarctos cinereus

Koalas are another type of marsupial that are native to Australia. They are arboreal meaning they spend the majority of their time in the trees. They regulate their temperature by keeping warm with thick fur and stay cool when it’s hot with a slow metabolism which helps to reduce heat production. They will also lick themselves to cool down in the hot, Australian heat.

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Koalas are herbivores and feed on the leaves of eucalyptus and gum trees. In a day, they can eat up to 3 pounds of leaves! 

17. Moose

Shiras moose 
Shiras moose  | image by USFWS Mountain-Prairie via Flickr | CC BY 2.0

Scientific name: Alces alces

Moose are large mammals that can be found in northern North America and northern Europe and Eurasia. They are associated with cold climates where it snows. Living in these cold climates obviously requires them to be able to stay warm and they are adapted to do so. Moose are incredibly large, which works in their favor when regulating body temperature.

Large mammals like moose have a larger surface area, which means a larger area that can hold in and retain heat. Their long noses are also an adaptation that allows the air that they breathe in to warm up before traveling to their lungs.

18. Opossums

Opossum on tree branch
Opossum on tree branch | image by ramendan via Flickr | CC BY-ND 2.0

Scientific name: Didelphis virginiana

While most marsupials are found in Australia, opossums are a species of marsupial that are found throughout much of North America. They are nocturnal and can be found in woodlands, rural areas and even neighborhoods. Like all other mammals, they are also of course endotherms.

However, their body temperature stays slightly cooler than most other endotherms. This cooler temperature range actually makes it so they are less susceptible to rabies, which does not tend to survive in the average body temps of an opossum. 

19. Sea Otters

Sleeping sea otter
Sleeping sea otter | image by NechakoRiver via Flickr | CC BY-ND 2.0

Scientific name: Enhydra lutris

Sea otters are a type of marine mammal that are found in the northern and eastern Pacific ocean. They have several adaptations that allow them to thrive in the chilly waters of the pacific. For example, their thick fur insulates them from the cold. They also eat an incredibly calorie-rich diet which requires them their metabolism to work over-time, thus producing more body heat.

Another somewhat unique adaptation is their muscles essentially leak out heat created from their metabolism working. Considering that they are very muscular, this creates a lot of extra heat for them to take advantage of.

20. Great White Sharks

Great white shark underwater
Great white shark underwater

Scientific name: Carcharodon carcharias

While most species of sharks or fish are not endotherms, great white sharks are a unique exception. They are not entirely endothermic, but partially or regionally endothermic. They can increase the temperature of parts of their body and keep them warmer than the surrounding water temperature. 

Their ability to keep their swimming muscles warm allows them to be more efficient hunters and hunt down their prey in a wider range of temperatures. However, this process is very energetically expensive for great whites.