Releaser facts for kids

A releaser is a special signal that one animal gives to another. This signal causes the other animal to react in a very specific way. Think of it like a secret code! The releaser is also called a sign stimulus. When an animal sees or hears this sign stimulus, it triggers something inside its brain called an innate releasing mechanism. This mechanism then makes the animal perform a specific action, which is called a fixed action pattern (FAP).

These behaviors are not learned; they are inherited. This means animals are born knowing how to do them. It's like they are "hard-wired" to react in a certain way when they get the right signal.

What is a Releaser?

A releaser is a signal that sets off a specific behavior. It can be something an animal sees, hears, smells, or even touches. For example, a baby bird might open its mouth wide and show a bright color inside. This is a releaser for its parent.

How Releasers Work

When an animal receives a releaser, it activates a special part of its brain or nervous system. This part is the innate releasing mechanism. It's like a switch that turns on a pre-programmed behavior.

Fixed Action Patterns (FAPs)

The behavior that happens after the innate releasing mechanism is triggered is called a fixed action pattern, or FAP. FAPs are usually:

• Stereotyped: They always look the same every time they happen.
• Innate: Animals are born knowing how to do them; they don't learn them.
• Unstoppable: Once a FAP starts, it usually continues until it's finished, even if the original signal goes away.

Examples of Releasers in Animals

Many animals use releasers in their daily lives for things like finding food, protecting themselves, or even finding a mate.

Baby Birds and Feeding

One common example is how baby birds get food from their parents.

• The Releaser: A baby bird squawks loudly and opens its beak very wide, showing the bright red or orange inside its throat. This signal is the releaser.
• The Fixed Action Pattern: When the adult bird sees this, it triggers its innate releasing mechanism. The adult then performs its FAP, which is to bring up food from its own throat and put it into the baby bird's mouth. Both the baby bird's begging and the parent's feeding are inherited behaviors.

Water Bird Dances

Some water birds, like the Great Crested Grebe, perform special "dances." These dances are very complex and were first studied by a scientist named Julian Huxley.

• The Releaser: When a pair of grebes meet after being apart, or on other special occasions, their meeting acts as a releaser.
• The Fixed Action Pattern: Both birds then perform a detailed dance together. This dance is their fixed action pattern. Scientists believe these dances help make the pair's bond stronger, especially since these birds often stay together for life.

Moths and Bats

Not all releasers benefit both animals involved. Sometimes, a releaser helps one animal survive while putting the other at a disadvantage.

• The Releaser: Some moths can hear the ultrasonic sounds that bats make when they are hunting. These sounds act as a releaser for the moths.
• The Fixed Action Pattern: When a moth hears a bat's sound, its innate releasing mechanism makes it instantly fold its wings and drop to the ground. This FAP helps the moth escape the bat.
• Bat's Response: Interestingly, some bats have also developed an inherited behavior. If they hear a moth, they might turn off their sound signals and glide silently for the last few feet to surprise the moth. This shows how animals adapt to each other's behaviors. This kind of quick, automatic reaction is also very similar to a reflex action.