Defensive behavior in Animals | Ethology

green snake camoflague

Defensive behavior in animals is defined as the type of behavior which is exhibited by an organism when they are being threatened by a predator or any other organism.It is opposite to that of offensive behavior in animals

The defensive behavior exhibited by organisms are:

1. Avoid detection by predator or threat.

2. Signalling other animals of presence of threats.

3. Living or Staying in groups.

4. Fighting back predators and threat.

5. Escaping from predators.

Avoid detection by predator or threat

Many animal uses certain defensive behavior and mechanism to avoid getting detected by threats or predators. These defensive mechanism includes:

A. Camouflage.

B. Mimicry.

C. Nocturnality.

D. Playing dead.

Camouflage

Camouflage is a defensive mechanism which is used by both plants, terrestrial and marine animals to blend into the environment. It is used by both predator and prey to avoid detection.

During this phenomenon, the organism/animal may change the color of skin or disguise themselves as the part of surrounding so that other animals cannot detect them.

Camouflage ( Defensive behavior ) exhibited by the flat-tail horned lizard which is a defensive behavior in animals
Pic 1: Camouflage ( Defensive behavior ) exhibited by the flat-tail horned lizard

Camouflage can be obtained in two ways:

With the help of pigments

Some animals can change the color of skin pigments to blend into the environment and to avoid detection.

Eg: Chameleons changing their skin color according to the environment.

Kallima inachus camouflage as a dead leaf which is a defensive behavior in animals
Pic 2: Kallima inachus camouflage as a dead leaf

With the help of physical structure

Some animals uses their physical structures such as furs, scales which helps them to blend into the environment.

Eg: Polar bears; who can blend into surrounding due to white colored fur.

Mimicry

Mimicry is defined as the defensive behavior in which one organism mimic or copy cat other animals to fool and escape from predators.

The particular animal can mimic the appearance, behavior, sound or odor of another animal to protect itself from predators

Eg: Viceroy butterfly mimic the appearance and behavior of Monarch butterfly to avoid being eaten by predators as Monarch butterfly are poisonous.

Mimicry which is a defensive behavior in animals
Pic 3: Viceroy butterfly (top) and monarch butterfly (bottom)

Nocturnality

Nocturnality is defined as the defensive behavior which is seen in certain animal species which remains active during the night and sleeps during the day.

There are many advantages of nocturnality which includes:

  1. The no. of predators are less at night.
  2. Low competition for food and water.

Nocturnality is seen in bats, turtles, snakes and certain bird species.

Bats flying at night which is a defensive behavior in animals
Pic 4 : Bats remains active at night

Playing dead

Playing dead is an animal behavior in which an animal acts as if it is dead to avoid being killed by predators.

It is seen in opossum , certain frogs , the common swift (bird), certain snake species such as barred grass snake etc.

Playing dead which is a defensive behavior in animals
Pic 5: Eastern hog nosed snake showing a defensive behavior as it is playing dead

Signalling other animal of presence of threat

Some animal warns other animals of threat or predator. Signalling includes:

  1. Alarm calls.
  2. Pursuit deterrent signals.

Alarm calls

Alarm calls or Alarm signals are defined as the defensive behavior which is seen in animals when an animal sees the approach of a predator alarms other animals present in the region.

It is seen in all types of animals which emits alarm calls when they see danger. Alarm calls may be visual, auditory or chemical signals.

The alarm calls are different for different for different dangers such as Monkeys have different alarm calls for tiger, lion, snakes and eagles.

Deer produces visual alarm calls. They generally uses their tail to produce alarm calls to warm fellow deers and other animals.

Chemical alarm signals can be seen in fishes which they releases to warn other fishes of danger

Pursuit deterrent signal

Pursuit-deterrent signals is seen in animals such as impala, deer, zebras etc. It is used to convince predators not to pursue them.

For example, gazelles, deers and impala stot, jumping high with stiff legs and an arched back. This is thought to signal to predators that they have a high level of fitness and can outrun the predator. As a result, predators may choose to pursue a different prey that is less likely to outrun them.

Pic 6: A gazelle slotting which is a defensive behavior

Living or staying in groups

Certain animal species such as zebras, deer, impala, monkey, wilder beest lives in groups or herds to ensure their safety.

Living in groups has many advantages such as:

  1. Quick and easy detection of predator.
  2. A large group can come together to fight off predator.
  3. A large no. of animals can confuse the predator.
Buffalo chasing a lion
Pic 7: Buffalo chasing a lion which is an advantage of staying in group.

Fighting back predator

Some animals have chemical and physical defensive structure which helps them to fight off predator.

Chemical defenses are generally seen in fishes and insects such as moths, butterflies, puffer fishes etc. which ejects or releases chemicals when they are caught by predators.

Some animals such as porcupines have defensive structures such as spikes, turtles have shells which protects them from predators.

Porcupines have spikes which helps them to defend themselves from predator.
Pic 8 : Porcupines have spikes which helps them to defend themselves from predator.

Escaping from predator

Escaping or running or flying away from predator is a common defensive behavior in all animals.

Animals generally escape from predators by running , jumping, swimming etc. Birds generally flies away from predator.

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