Available at http://planet.uwc.ac.za/nisl/Eco_people/Presentations/

ANIMALS

WHY DO THEY LIVE IN HERDS ?

Many animals live in herds also known as social groups. This is mainly done in order to survive on a day-to-day basis.

When living in social groups it is such easier to communicate with other individuals and this increases the efficiency of the whole group.

INTRODUCTION

Introduction cont…The sizes of social groups varies

from species to species.There are numerous reasons why

animals live in groups and these are all inter linked.

Even though there are many advantages to living in social groups, there are also some disadvantages.

THERE ARE NUMEROUS REASONS AS TO WHY HERBIVORES LIVE IN

HERDS..

Feeding efficiency

protection from predators

Reproductive efficiency

Division of labour

Social transmission of information

Reproduction efficiencyThere are advantages that animals obtain from being social, however these advantages are different within each species and each has its own pattern of social organization, D Barash (1982).

Benefits amongst species does not occur across-the-board.

Within social groups male and female encounters are easily facilitated and this makes reproduction more efficient, as no time is wasted searching for mates, Barash (1982).

Males and females that do not live in organized colonies often find it difficult to integrate with the opposite sex and the entire process of finding a suitable partner is rather time consuming.

“Nothing is all good or all bad”, according to Barash (1982).

Avoiding Predation

Predation is an important factor which plays a major role in the structuring of social groups.

There is safety in numbers.When individuals remain in large

groups it is much easier to avoid predators.

The larger the social group, the greater the chances of escaping predators.

The confusion effect decreases the likelihood of predation.

When avoiding predators, social groups spend less time in antipredator vigilance.

Alarm calls . . .

Animals which live in large groups often make use of alarm calls to let individuals of the same group know when predators are spotted.

Efficient feeding Animals should not only ensure that

they reproduce successfully and avoid being captured by prey, but they should also ensure that they receive enough food to survive, Barash (1982).

When individuals search for food it is much easier to find food when in part of a group as a larger area can be covered and at the same time there is enough protection.

Animals living in social groups have an advantage over animals who are solitary when it comes to feeding.

Individuals which are part of a group are able to capture prey larger than them irrespective of the average size of individuals in the group.

Conditioning their environment

The biological conditioning of the environment is an effect that animals use to modify their environments.

Division of labourAmongst large social groups there

is a greater chance of labour being split between the individual within the group, according to Barash (1982).

As individuals specialize in their behaviour, they increase the efficiency of the group, according to Deag (1980).

Social transmission of information

Within social groups individuals are able to obtain information by watching and imitating other individuals.

Warthog- Phacochoerus aethiopicus

They occur in Northern and Southern savannas.

Adult female and male do not always live together all the time and get together for mating.

Some social groups are small and some are large

Elephants

Species Loxodonta africana Their societies are made up of

Matriarchal clans General composed of cow herds Males live alone

ReferencesBarash DP (1982) Social biology

and behaviour. Elsevier Science Publishing Co.,Inc., pp: 187-203. ISBN 0-340-28460-9

Deag JM Social behaviour of animals. The Camelot Press Ltd, Southampton. Pp 75 ; 82. ISBN 0-7131-2770

References cont… King JA (1955) Social behaviour

and social organization, and population dynamics in a black tailed prairie dog town in Black Hills of South Dakota. Contribution of the Laboratory of Vertebrates Biology. Ann Arbor: university of Michigan, Rep. No. 67