Transcript Michelle_baatjies

ANIMALS
WHY DO THEY LIVE IN
HERDS ?
Available at http://planet.uwc.ac.za/nisl/Eco_people/Presentations/
INTRODUCTION
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 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 efficiency
There 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 labour
 Amongst
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
References
 Barash
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 07131-2770
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