Prides, Coalitions and Infanticide Among Lions
Evolutionary and Behavioural Reasons These Big Cats Stay in Groups
Jul 21, 2009
A pride is made up of related females and their offspring, which can be male or female cubs. Prides vary in size and include any nomadic males that have taken over the pride. Male lions are called nomads if there is only one or two traveling together. When there are more than two males traveling together, they are collectively called a coalition.
Coalitions of Lions
A coalition is the term used for a group of male lions that are related. Coalition refers to a group size anywhere from three or more males, and generally no more than nine males would form a coalition. When a coalition of males takes over a pride they kill the small cubs and evict the sub adult males and often the sub adult females that have not yet reached breeding age.
Occasionally the mother of the evicted sub adult will leave the pride as well, until the sub adult has reached maturity. If not yet evicted, male lions tend to leave their pride before they reach sexual maturity. Males show signs of sexual maturity at twelve months old, but are not fully mature until about thirty months of age.
The average time a coalition of males gains residency within a pride is two years before another coalition evicts them and takes over. Coalitions of three or more males have the best chance of taking over a pride, staying with the pride for a long time and having more mating opportunities than larger or smaller coalitions.
Large coalitions occasionally gain access to neighboring prides, which again increases their potential offspring numbers. This usually occurs when their daughters reach sexual maturity. There is no inbreeding within a pride and males leave the pride to mate with non-relatives.
A Pride of Lions
A pride is made up of related females and their cubs and can have up to 18 females. Prides vary in size from a few as four lions to as many as forty, including lionesses, cubs and anywhere from one to six nomadic males that have taken over. Male lions compete for sexual control of a pride, and one of the reasons females live in such large prides is to protect their cubs against infanticidal males (males that kill infants/cubs).
A male lion is about one and a half times the size of a female, so to defend her cubs she will often need the help of other females. Females protecting their cubs will often sustain serious injury and on occasion a fight can result in the death of a lioness.
Female lions do not mate again until their cubs are 18 months to two years old, so by killing the cubs, males will ensure a female is ready to mate again within weeks, possibly days of losing her cub. This ensures the male lion then fathers the next litter, thereby potentially increasing his evolutionary fitness.
You may also like to read The Sexual Behaviour of Lions.
Resource and further reading:
Alcock, J, 2005, ' An Evolutionary Approach to Animal Behaviour, The Evolution of Mating Systems', in Animal Behaviour Eighth Edition, ed. Sinauer Associates, Inc., Sunderland, chap 1, 11.
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