What is an Adaptation?

It is the adjustment of organisms to their habitat to help improve their chances of survival.

Adaptations help an organism find food and water, protect itself, and manage in extreme conditions. They can be physical or behavioral adaptations.

Aquatic animals live in freshwater (lakes and rivers) and saltwater (seas and oceans) habitats and have special adaptations.

Let’s dive in and learn more about the adaptations of aquatic animals!

Aquatic Adaptations – Breathing

Aquatic animals have different types of breathing adaptations:

  • Most fish have gills as respiratory organs to take in dissolved oxygen from the water.
  • Some animals, such as whales and dolphins, have blowholes on the top of their head for breathing. They come to the water’s surface to breathe.
  • Frogs use their skin to breathe in oxygen when underwater.
  • The diving bell spider uses air bubbles stuck on the hair of their abdomen to provide oxygen.

Aquatic Adaptations – Movement

Aquatic animals have particular adaptations to help them swim in water:

  • Streamlined bodies (tapered on both ends) to help them swim fast.
  • Most fish use different kinds of fins instead of limbs for movement:
    • The tail fin propels the fish forward
    • The pectoral fin helps with steering and movement
    • The dorsal fin helps with stability and balance
  • Whales, dolphins, sea turtles, and penguins have flippers, which are flat, broad limbs made of bone to help with movement.

Fun Facts

Here are some fascinating aquatic adaptations

  • Sharks have small holes on their nose to sense the electric fields of other animals. These help them detect prey that is not moving.
  • Sea stars can grow back their arm if they lose one, and some species can regrow their entire body from just one arm.
  • Stingrays have eyes on top of their head to help them see when they are hiding in the sand.
  • Some species of anglerfish have a special bait-like structure with fluorescent bacteria to attract prey.


Let’s quickly recap what we learned about aquatic animal adaptations:

  • What is the breathing adaptation of whales and dolphins? Blowhole on top of the head
  • What kind of a body do aquatic animals like sharks have to help them swim faster? Streamlined
  • What are the two body parts that help aquatic animals with movement? Fins and Flippers
  • What respiratory organ helps fish breathe in dissolved oxygen from the water? Gills
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