#foraging behaviour

Foraging Behaviour in Animals (4)

Search Time - length of time taken to look for food

Pursuit Time - length of time taken to catch the food

Energy gained from the food must be higher than the energy used in searching and handling the food

To ensure that the maximum energy gain is achieved, animals enploy optimal foraging strategies

Foraging behaviour involves using sense (see, hear, smell) to find food

Social Mechanisms for Obtaining Food and for Defence

Cooperative hunting ensures that all members of the group feed even the weaker ones

By working in groups there is more chance of finding bigger animals to feed on

Dominance hierarchy exists - strongest member at the top and others ranked beneath

This ensures strongest member survives and reproduces passing on his strong genes

OBTAINING FOOD - ANIMALS

Foraging Behaviour

This is the search for food involving patterns of movement called search pattens.

These

Increase the chance of finding food.

Vary with the availability of food.

Vary with the type of food.

Are species specific

Foraging Behaviour in Social Insects

The survival of colonies of social insects is dependent on food supply. If a forager finds a good food source it must share this to the rest of the colony.

Ants

There insects will wander about in search of food. If successful, they move 'straight' back to the nest leaving a chemical trail. The other ants will follow the trail and will exploit the food source. Re-marking of the trail will occur while the food lasts. 

Bees

If a foraging bee finds a good food source, on returning to the hive it will carry out a waggle dance. The orientation and length of this dance communicates the direction and distance to the food source.

Foraging Behaviour in Higher Animals

 Although instinct plays a great part in foraging behaviour, an element of learning is involved. There are many different strategies in foraging, some involving packs of animals (see cooperative hunting) and other individuals.

*Table to show different strategies used by individual hunters

Economics of Foraging Behaviour

The way animals get their energy can be looked at in terms of simple economics.

Selling price - Cost = Profit

In the case of foraging behaviour

Energy gained from food - Energy expended = Net energy gain or loss

Energy can be expended in

looking for food = search time

catching = pursuit time

preparing and eating = handling time

avoiding predators while foraging

If an animal operates at a loss for too long it will die. Ideally an animal will choose behaviour patterns which will maximise energy gain.

Choice of Behaviour Patterns

Food in limited supply If food is scarce then the animal is non selective in its choice of prey. This reduces the energy 'spent' on further search

Food plentiful Animals will choose prey that is easily caught. This reduces the energy 'spent' in further pursuits.