Animals’ Defense Mechanisms

What is a Defense Mechanism?

Animals live in harsh conditions and are in constant danger of being preyed upon.

A defense mechanism is some type of strategy or physical adaptation of a species to protect itself from predators.

Defense mechanisms can be chemical, physical, color, and behavioral.

Let’s explore these different types of defense mechanisms.

Chemical Defense Mechanism

Some animals store poison in spines or glands, releasing it when attacked. Some release a chemical spray to ward off predators.

• Skunks spray a pungent-smelling chemical. 
• Stingrays and Scorpionfish use poison-tipped spines.
• Octopus and Squid release poison into the water.
• Poison Frogs are brightly colored frogs that have poison secreted in their skin.

Physical Defense Mechanism

The physical structures of some animals help in defense.

• Shells – Clams and snails have hard shells that they can withdraw into.
• Sharp Spines – Porcupines have quills that are attached to their body. 
• Exoskeleton – Insects like cockroaches have a hard outer skeleton for protection.
• Electric Organs – Electric Eels can produce an electric shock to stun predators.

Color Defense Mechanism

Some animals use camouflage to escape from predators. There are four types of camouflage.

• Concealing Coloration – The animal’s color blends in with its surroundings. 
  • Arctic fox that turns white in winter.
• Disguise – The animal looks like something else entirely. 
  • Decorator crabs deck themselves with seaweed and corals.
• Disruptive Coloration – Use patterns like spots or stripes to confuse the predator.
  • Stripes on a zebra
• Mimicry – A harmless animal makes itself look like a poisonous animal.
  • The Viceroy butterfly looks like the poisonous Monarch butterfly

Behavioral Defense Mechanism

Animals use specific behavioral strategies to escape from predators.

• Detecting Predators – The Common Dwarf Mongoose posts sentries that watch out for birds of prey.
• Avoiding Predators – Merriam’s kangaroo rats are nocturnal animals, but they change their feeding time to the evening on full-moon nights to avoid predators.
• Surviving Predator Encounters – Opossums pretend to be dead to discourage attack from predators

Fun Facts

There are some really fascinating animal defense mechanisms in nature!

• The Texas Horned Lizard squirts blood from its eyes at an attacker.
• Malaysian Exploding Ants self-destruct to defend their colony. 
• Cuttlefish can change their skin color and body shape to blend in with the surroundings.
• Sea Cucumbers eject their internal organs at the enemy to entangle them.
• Hagfish expel a slimy substance that mixes with water to clog the predator’s gills.

Review

Let’s quickly recap what we learned about defense mechanisms.

• What are the four types of defense mechanisms of animals? Chemical, Physical, Color & Behavioral
• Which animal sprays a pungent-smelling chemical to repel predators? Skunk
• What type of camouflage is it when a harmless animal appears like a poisonous one? Mimicry
• What kind of animal has a hard exoskeleton as a physical defense mechanism? Insect
• What are two behavioral strategies to escape from predators? Detecting and Avoiding Predators