Some animals are more affected by the temperatures in their environment than other animals, so they seek external heat sources to regulate their body temperatures. These types of animals are called ectotherms. Examples of ectotherms mostly consist of cold-blooded animals. In contrast, animals that can generate body heat internally are called endotherms.
Let’s learn more about what makes an animal an ectotherm and check out these 15 examples with pictures and some interesting facts.
What is an ectotherm?
The body temperature of ectotherms fluctuates with external temperatures because they can only generate low levels of internal heat. These animals need to absorb heat from their surroundings, such as the sun’s rays or the warm waters they inhabit.
They also have different behaviors to manage their body temperatures, including migration, hiding, or sun-bathing from different angles. Ectotherms are considered to have lower stamina than endotherms since they often need daylight to absorb heat from the sun.
15 examples of ectotherms
Most reptiles, amphibians, and fish are ectotherms. Here is a list of 15 examples of animals with body temperatures that are impacted by their environment.
1. Corn Snakes
Scientific name: Pantherophis guttatus
Corn snakes are also called the Red Rat snake and are common pet snakes in North America. They are docile, non-venomous, and have many morphs.
These snakes like to hide and burrow. Adults can also climb trees. Ideal temperatures for them range from 75 to 82 degrees Fahrenheit for cooler climates and 80 to 85 degrees Fahrenheit in the heat.
Scientific family: Viperidae
Rattlesnakes are venomous snakes with a segmented rattle on their tail tips that creates a buzzing sound when they feel threatened. These snakes live throughout North and South America, with large populations in southwestern U.S. states like Arizona.
You can find rattlesnakes basking in the sunlight or lounging in the shade to help their bodies adjust to a comfortable temperature. In cold months, rattlesnakes tend to hide in dens or burrows with steady temperatures.
Scientific family: Testudines
There are around 356 species of turtles worldwide, except in Antarctica. These animals live on land, in salt water, and in freshwater habitats. Their distinctive features are turtle shells on their backs that are part of their bodies and limbs that can either retract into the shell or are adapted for swimming.
Turtles will regulate their body temperatures in various ways, including:
- Moving to waters with different temperatures
- Burrowing in the sand
- Basking in the sun
4. Marine Iguana
Scientific name: Amblyrhynchus cristatus
The Marine Iguana lives only on the Galapagos Islands and is adapted to island lifestyles. They can climb coastal cliffs and have a flat tail, allowing them to swim efficiently.
During the day, they often bask in the sun to raise their body temperature. Since they often dive for algae, and the waters can lower their temperatures, they need to ensure they have sunbathed enough before finding food. At night, you can see them piled on top of each other to stay warm and maintain body heat.
5. American Alligators
Scientific name: Alligator mississippiensis
American alligators are large reptiles looking similar to crocodiles. The males are typically larger than females, growing up to 15 feet in length. You can find American alligators in the Southeastern U.S., especially in Florida.
Alligators prefer temperatures between 82 to 92 degrees Fahrenheit when they are most active. You can often see them basking in the sun to raise their body temperatures. During the winter months, they will bury under mud or remain underwater to keep warm.
Scientific name: Carassius auratus
Goldfish are common household pets. In fact, they have been pets for over 2000 years, dating back to ancient China. These fish can grow more than a foot long and live over 40 years when cared for in the right environments, including the right water temperatures.
Tank temperatures between 68 to 74 degrees Fahrenheit are ideal for goldfish. Anything warmer than 80 degrees Fahrenheit can stress them out. However, these fish can survive in close to freezing water in the wild if they have to.
7. Tree Frogs
Scientific name: Rhacophoridae
Tree frogs are a type of amphibian that mostly lives in trees. They have unique sticky paddings on their feet that allow them to cling to bark, branches, and wet leaves. You can find over 800 species of tree frogs around the world.
When tree frogs are exposed to high levels of heat, they can overheat or dehydrate easily. For these reasons, they often live in moist areas or near water bodies to dip in the water. They also hide under tree barks to cool down.
Scientific name: Bufonidae
Toads are amphibians that differ from most frogs due to their appearance. They typically have crests behind their eyes, warty bodies, and parotoid glands that secrete toxins.
Although they have drier skin than most frogs, toads still try to keep their skin moist by staying in wet habitats. The water evaporation off their skin can help cool them down. Some toads will brumate in the winter months when the temperatures drop below 75 degrees Fahrenheit.
Scientific name: Salamandridae
There are around 112 species of salamanders in North America, and most of them live in the Appalachian region. Salamanders are also found in other areas of the world, including the Chinese Giant salamander in China, one of the world’s largest amphibians. They can grow to nearly 6 feet long and up to 110 pounds.
Most salamanders are smooth or even slimy. They keep their skins moist and often live in water or stay near water to regulate their body temperatures. Depending on the species, each salamander has a different tolerance to cold. For example, the Siberian salamander (Hynobias keyserlingii) can survive in temperatures below freezing.
10. Bearded Dragon
Scientific name: Pogona Vitticeps
Bearded dragons are reptiles native to warm, arid habitats in Australia, such as deserts, savannas, subtropical woodlands, and scrublands. However, they are very popular pets around the world.
Their name comes from the spiny projections under their necks that can puff up when they are threatened, making them look like they have beards. These animals often bask in the sun or other heat sources to provide body temperature. Their heads can also collect water, running it to their mouths, so they stay hydrated and cool.
Scientific name: Homaridae
Lobsters are large crustaceans that live in marine habitats. Their body temperatures are influenced by the waters they inhabit. Depending on the species, you will find them in different oceans around the world.
For example, warm water lobsters live along the coast of Florida, California, or the Caribbean, where the climate is warmer. When water temperatures change, you can find these lobsters migrating in groups to find warmer locations.
12. Hermit Crabs
Scientific family: Paguroidea
Hermit crabs are unique crustaceans that need to occupy shells that they carry on their backs to protect their bodies. Over 800 species of hermit crabs exist globally, and almost all are ocean-dwelling. However, you can find them on the beaches, searching for new shells to call home.
These tropical crabs prefer warmer temperatures of above 75 degrees Fahrenheit. However, they tend to be active at night when the sun won’t burn them. Hermit crabs can also hide in their shells when they sleep or need shelter and protection.
Scientific family: Chamaeleonidae
There are around 170 species of chameleons, and each ranges in size and color. The smallest is the Leaf chameleon (Brookesia) that can fit on the head of a match and grows up to 0.5 inches. The largest is the Parson’s chameleon (Calumma parsonii), growing up to 27 inches long.
Chameleons can change their skin color in response to their emotions and use this as a form of communication. Their skin color can also change depending on the temperature and levels of humidity in their environment. In the mornings, chameleons often bask in the sun to raise their body temperature for energy to start their day.
14. Honey Bees
Scientific family: Apidae
Honeybees are as their name suggests, insects that produce honey in their hives. They are also important pollinators. When these bees lose their stinger, such as by using it to sting, they will die.
The majority of honey bees are ectothermic. However, these are interesting animals since they have the ability to change, with some honey bees being endothermic when in the hive. Honey bees often heat their hives by vibrating their flight muscles in the cluster. To prevent too much heat from escaping out the top of their hive, they also place insulation there to capture rising heat.
Scientific name: Selachimorpha
While some sharks, such as the shortfin mako (Isurus oxyrinchus), are endothermic, the majority of sharks are ectothermic. Common sharks such as the Tiger shark (Galeocerdo cuvier) or the Great Hammerhead shark (Sphyrna mokarran) are cold-blooded and rely on the ocean environment for heat.
Sharks preferring warm temperatures spend most of their time swimming in tropical waters. Sharks will also migrate to warmer waters during season changes to stay in optimal temperatures.