Outforia Quicktake: Key Takeaways
- Cold-blooded animals, or ectothermic species, rely on their surroundings to regulate body temperature and have a slower metabolism.
- These animals, including fish, amphibians, insects, and reptiles, adapt to various environments and temperature ranges.
- Cold-blooded animals often become inactive during colder months, with some resorting to hibernation.
- Thermoregulation strategies vary among species, including basking in sunlight or seeking shade, and some are sensitive to even minor temperature changes.
- Some cold-blooded animals, like certain octopi, have blue blood due to copper-based proteins, making them more efficient at transporting oxygen in colder environments.
All cold-blooded animals are called ectothermic. These species rely on their surroundings to regulate their body temperature.
However, ectothermic animals aren’t always cold. Some lizards thrive under the desert sun. In fact, their internal temperatures reach over 120 degrees Fahrenheit. Amphibians and fish tend to like the colder water, and their bodies adjust to their environment.
Being cold-blooded means always thinking about thermoregulating (maintaining an ideal temperature). Their cold blood comes with a slower metabolism. Unlike humans or other warm-blooded species, their metabolism does little to achieve homeostasis.
When these animals live in areas with winter, keeping up is difficult in the cold. The cold blood limits the temperature they can handle before freezing, but these animals learn to adapt.
Hibernating animals like bears, cold-blooded creatures spend the winter months less active. Some will not feed in an effort not to move.
Our list below will highlight four common kinds of cold-blooded animals and specific species you may encounter.
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Most sharks are cold-blooded creatures, and their body temperature will match the water. The term cold-blooded can be misleading since some sharks live in warmer water.
Sharks have a complicated vascular network throughout the body. The system can carry oxygen throughout the body. As they move, their body heats to the temperature of the water. It is part of the reason sharks are unable to stop swimming.
Sharks capable of reaching high speeds can maintain blood temperature warmer than the water. Their special arrangement of blood vessels allows them to heat their body and expend more energy. The process happens when the cold oxygen from the water passes through deoxygenated blood vessels.
Octopi are found in oceans around the world. These impressive creatures have adapted to live in a variety of temperatures.
When it comes to size and habitats, octopi follow Bergmann’s rule. The warmer water octopi tend to be smaller and live in shallow waters. Octopi found in arctic seas, or ocean depths are more substantial.
Some octopi have blue blood, which allows them to live in the deepest parts of the ocean. This blue pigment comes from copper-based proteins in their bodies. The change in proteins gives the blood its blue color and is more effective in moving oxygen at lower temperatures.
Trout are among the most sensitive to changes in water temperature. Avid anglers chase trout in cold lakes and up mountain rivers.
Different species handle temperatures differently, and brook trout are among the most sensitive. When rivers warm over the summer, trout move to springs fed from groundwater.
In larger rivers, their bodies are a few degrees Celcius less than the river. The trout were observed retreating to springs during the day to lower their body temperature.
There are hundreds of different species of eels found throughout the world. Species to species, eels have adapted to live in warm and cold water. An ideal range for eels is around 20 degrees Celcius.
Eels are sensitive to environmental changes. They even shut down if the water changes drastically. The sensitivity drives the eels to migrate to better water. Their hypothesis about why is that they are thermoregulating. Researchers observed eels moving into warmer waters at night to warm up.
The electric eels native to South America enjoy living in warmer swamps. The waters lack a lot of oxygen, so eels take breaths of air via a cavity on their head. Their cavity oxygenates the blood and fuels its movement.
Like all species of fish, catfish are ectothermic. They are at the mercy of the water temperature for their internal regulation.
Blue catfish and some other species can get massive. Such size requires lots of movement and feeding to grow to so large. Without any need to regulate temperatures, this species focuses on gaining size and security.
Looking at a jellyfish, one would assume they cannot regulate their body temperature. No species of jellyfish is capable of maintaining its body temperature. They are one of few species in the ocean that thrives in warm water.
Jellyfish have adapted their respiratory system to function in low oxygen. So many species can live near the equator because of this. Other predators aren’t drawn to the warm, low-oxygen water where jellyfish can thrive.
All frogs rely on the sun, water, and shade to control their body temperature. Moisture and humidity are necessary for the survival of frogs in high temperatures.
When frogs have access to water, they can cool off immediately. But if they want to hunt in the daylight, they can retain moisture in their skin. When the water evaporates in the sunlight, their bodies cool off.
During the coldest months, some frogs will resort to hibernating. During dormancy, frogs will remain below lake ice or buried in mud. Their skin takes in oxygen from the surrounding environment to support the hibernation.
Toads are very like frogs in how they interact with their environment. They rely on external moisture to maintain cooler body temperatures in certain environments.
In a study of the dwellers toads, researchers observed toads storing energy and moisture for certain periods. During hours when prey is less available, toads would retain additional moisture. Researchers think this behavior allows them to move without concern for thermoregulation in the heat.
Salamanders are among the most sensitive amphibians. A healthy population is a sign of a clean environment. But, without moisture, salamanders risk death.
Lungless salamanders are known for living in microhabitats. These small areas have optimal living conditions for creatures that need external moisture. Terrestrial salamanders inhabit more environments but are still very sensitive to dry climates.
Butterflies are cold-blooded animals who love the heat. They need heat and cannot fly if their internal temperature is below 30 degrees Celcius.
Butterflies lie still on plants to soak up sunlight whenever they want to fly. When we see them gently flapping their wings, the butterflies are generating heat for flight. Butterflies are also known to shiver, and the rapid shaking warms them up for short flights.
Butterflies do not stick around for long. Most species have a lifespan of 2 to 3 weeks and are only alive to reproduce. The monarch butterfly famously migrates long distances to reach warmer temperatures.
Social insects like bees rely on their colonies to thermoregulate. Hives all work together and keep internal temperatures over 35 degrees celsius when outside temperatures are freezing.
Bee antennae can detect subtle temperature changes as low as .25 degrees Celcius. They use this finely tuned system to construct intricate nests capable of doing the thermoregulation for them.
Hives will have a structure designed to keep heat trapped. Insulation can be provided by tree trunks or layers of honey. When all bees are inside a hive, shivering or moving about, the heat is enough to allow them to fly at any temperature.
The structure of the hive can also be optimized for cooling. Some hives will have airways designed to funnel cooling air to the hive. Bees have one of the most developed thermoregulation strategies in the animal kingdom.
Ironically, a creature that loves damp areas relies heavily on the sunlight. Centipedes need to warm their bodies before they can think about moving and eating.
Cold weather drives the insects into hiding. While they are not hibernating, they might as well be. Centipedes will remain mostly inactive for months before the spring heat brings them out. The cold drives the centipedes into our homes, making for an irritating guest.
Bigger-bodied desert centipedes are especially sensitive to a lack of heat. Their larger body size requires more heat to power it. The smaller house centipede can move quicker and function in the cold.
Scorpions are temperature-dependent creatures that crave direct sunlight. There is a good reason scorpions rarely live outside of the desert. Despite being cold-blooded, its internal temperature remains around 35 Celcius.
Their dry, natural habitat does not mean the species can function without water. Scorpions are susceptible to drying out during droughts. Their bodies shrivel, and their activity levels will drop. Without rain, their exoskeleton is unable to cool the body.
When kept as a pet, scorpions need a sun lamp to survive. Like any cold-blooded pets, scorpions need heat to move around the tank.
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A crocodile’s ideal internal temperature is between 30 and 33 degrees Celsius. While that is not cold, these are still cold-blooded creatures. They rely on the environment around them to regulate their internal temperature.
Their tough skin is designed to retain moisture and allows them to lay in the sun to warm their bodies. In warm, sunny periods, the crocodiles retreat to the water and shade to prevent overheating.
Another method to prevent overheating is when crocodiles bask with their mouths open. The sun still hits their body, while the brain gets cooled from the airflow.
Prolonged cold weather forces crocodiles into inactivity. During winter, only the sunlight can warm their bodies. Crocodiles won’t eat for months since they expend no energy moving.
Snakes need sun and shade to warm and cool their bodies. Snakes are sensitive to the cold and will burrow to escape the wind.
Without proper access to heat, snakes will go inactive. Wild snakes consume giant meals before cold spells to sustain them while they burrow. If snakes get to bask in the sun during the cold, they enable themselves to move or hunt.
Pythons and other species of snakes will shiver to warm themselves. As muscles rapidly contract, they begin to produce heat. Snake eggs are vulnerable to the cold, and mothers will wrap their eggs and shiver.
Lizards will conduct heat from the ground or insolate heat from sun rays. Different species adapted to extreme environments around the world.
Lizards found in the Australian outback, like thorny dragons, can soak moisture through their skin. Without this adaptation, the lizard would struggle to move or eat during the hottest parts of the day.
Chameleons are famous for their ability to camouflage in their surroundings. One little-known reason for this behavior is temperature regulation. Chameleons can change to shades that soak up less heat. If the sun is too much, it changes to a brighter, less absorbent shade.
4. Sea Turtle
Sea turtles are reptiles that need water to control their body temperature. The optimal internal temperature is between 25 and 27 Celsius and is high for such a low metabolic rate.
Their slow metabolism makes them susceptible to cold snaps in the water. If oceans drop below 10 degrees Celsius, their bodies cannot keep up with blood flow. Cold-stunned turtles seek out sunlight and are vulnerable before they thaw.
Many species of sea turtles are known to migrate. The ideal breeding grounds are warmer and more tolerable in cold months. Researchers tracked one female ladderback over 12,000 miles in her lifetime.
Iguanas rely on sunlight to keep themselves going. Iguanas never adapted any ability to withstand the cold and typically inhabit tropical climates.
Invasive species of iguanas in Florida are a nuisance to residents in the cold months. When temperatures stay below 5 degrees Celsius, the iguanas will paralyze. Their blood is too cold to move, and they lay stunned in yards, streets, and sidewalks, waiting for external heat.
Green iguanas were studied to learn how dinosaurs regulated their internal temperature. Iguanas have a complex circulatory system in their head. The system is responsible for sending messages about heating and cooling to the body.
Researchers found green iguanas have a vast network underneath their jaw. The muscles here constrict and contribute to the blood flow throughout the rest of the body.
Blood vessels from the nasal passages may send messages about heat transfer. It is speculated dinosaurs with similar genetics would have thermoregulated similarly.
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Cold-Blooded Animals FAQ
Do cold-blooded animals get cold?
Yes, they get cold. If cold-blooded animals live in an area where the temperature fluctuates, they risk freezing.
Their metabolism is much slower and is not responsible for maintaining their body temperature. The sun and outside environment are entirely in charge of whether the animal can warm itself.
Can a human be cold-blooded?
Humans cannot be cold-blooded. If a human’s temperature drops below average levels, our bodies suffer tremendously.
Our bodies use warm blood and high metabolism to maintain a constant temperature. Like cold-blooded animals, we are susceptible to changes in temperature.
What’s the coldest temperature an animal could survive?
Arctic animals are the best equipped to handle the cold and live in sub-zero temperatures. Extreme temperatures reach -70 degrees Celsius, and warm blood is not enough to survive. Some species grow thick coats while others hibernate. Whatever it is, all species are forced to adapt to such extreme cold.
Are dinosaurs cold-blooded?
One of the oldest questions in paleontology got a definitive answer this year. Most species of dinosaurs were warm-blooded..