Cold-blooded animals are animals whose body temperature changes with the environment rather than staying constant like in birds and mammals.

What “cold-blooded” means

  • Cold-blooded animals (also called ectotherms) rely on external heat sources such as sunlight, warm rocks, or warm water to raise their body temperature.
  • Their internal temperature usually follows the surrounding temperature, so they warm up in the sun and cool down in shade, water, or burrows.
  • Because they do not spend much energy producing their own heat, their metabolism is generally lower than that of warm-blooded animals.

Main groups of cold-blooded animals

  • Reptiles: snakes, lizards, turtles, crocodiles, and alligators are classic cold-blooded animals.
  • Amphibians: frogs, toads, salamanders, and newts depend strongly on environmental temperature.
  • Fish and sharks: most bony fish and many sharks are cold-blooded, matching the temperature of the water around them.
  • Many invertebrates: most insects, spiders, and many other invertebrates are also ectothermic.

How they cope with temperature

  • When it is warm, cold-blooded animals become more active because heat speeds up their muscles and metabolism.
  • When it is cold, they slow down, often becoming sluggish, hiding under rocks, in mud, or in burrows to conserve energy.
  • Many species enter torpor, diapause, or hibernation-like states in winter, greatly lowering activity and energy use.

Advantages and drawbacks

  • Advantages:
    • Need far less food than similar-sized warm-blooded animals, so they can survive where prey is scarce, such as deserts.
* Can grow to a wide range of sizes because they are not constantly burning calories to stay warm.
  • Drawbacks:
    • Activity is limited by ambient temperature; in cold conditions, they may not be able to hunt or escape predators effectively.
* Many species must time feeding, breeding, and movement to warmer periods of the day or year.

Quick examples

  • Frog, snake, lizard, turtle, crocodile, many fish, and most insects are all cold-blooded animals.

Information gathered from public forums or data available on the internet and portrayed here.