Panthera leo : a species account

Social Organization & Behaviour

“Gregarious, territorial, matriarchal society, communal care, male coalitions.” Lions are the only truly social cat.

References e.g. [18] – [19], [36] – [38], [42], [46], [56], [61] – [65], [75]

The basic units of lion social organization are resident prides occupying hunting territories of a size that can sustain the pride during times of scarcity. Lion densities, home territory size and social group size vary in parallel with habitat suitability and prey abundance, generally larger in moist grasslands where game is plentiful and smaller in drier bush with fewer prey animals.

Home territories range from 20km2 in the most suitable habitats to more than 500 km2. The average area of nine Serengeti prides was c. 200km2. Pride ranges and territories may overlap but each pride maintains a core area where most activities are undertaken with little interaction with other lion groups. Territories are stable except in periods of hardship. If an area becomes devoid of lions (as a result of disease for example) this will be followed by an influx of competing lions to claim the territory.

Prides can attain 40 members, however the average pride, both in Kruger NP and the Serengeti, consists of 13 members. In Kruger, the average composition of 14 prides totalling 181 lions was 1.7 adult males, 4.5 adult females, 3.8 sub-adults, and 2.8 cubs (including yearlings). Females outnumber males by a substantial margin, despite a near 50% male/female birth ratio. This is probably due to the tendency of males to be nomads, take on more dangerous game, and be killed in pride takeover attempts.

In larger prides it is rare for the whole pride to be together, but individuals or small groups, typically of three – five members will scatter throughout the prides territory for days or weeks at a time, especially in arid environments or times of prey scarcity. There is no hierarchy between females, and no particular bonding between any pride members. A pair of females will be found together no more than 25 – 50% of the time.

Presence within a pride’s territory is not a sign of membership as many lions are transient or “squatters”. Membership of a pride can only be distinguished by an amicable greeting ceremony performed between pride members. Any member without the confidence to perform the ceremony will be treated as outsider.

Lions will defend their territory against lions of the same gender, but most encounters do not result in fighting; usually one pride will skulk off under the watchful gaze of the other.

The adult females in a pride are usually related and will stay within the natal range unless there is a scarcity of food, under which instance two-year old females will be forced to leave. Each pride has an apparent maximum number of females. In Kruger NP the number of lionesses remained constant in six neighbouring prides for two-and-a half years, even though the actual membership of the prides changed. If the number falls below the capacity for the home range sub-adult immigrants may be allowed to join.

Male Coalitions

Due to the nature of a large number of females in grouped social structures, males are able to monopolize breeding, which has led to fierce competition between males and is behind the sexual dimorphism in lions, alone amongst the cats.

Males are forced to leave the natal pride at age two – three years and enter a nomadic phase until they are large enough to challenge a sitting dominant male for control of a pride, at around five – six years old. Brothers will usually stay together and form a coalition, oftentimes joined by males ousted from other prides.

In the Serengeti population, 42% of coalitions were formed with at least one unrelated male. The apparent benefits to winning and sustaining dominancy of a pride through increased strength awarded by a coalition are clear, however studies have shown that most coalitions are small, and many males stay as lone nomads. Out of 40 sightings of nomadic males in the Serengeti all but three were pairs and singles. Coalitions up to seven-strong have been recorded.

Most pride tenures last around two years, however collations of three or four males often last longer. Coalitions of more than four males are rare as these coalitions often take over more females than they can defend, resulting in fewer surviving offspring.

Infanticide in Lions

On taking over a pride the males usually kill all offspring under a year. Females may defend their cubs to the death, or leave the pride with them. Older juveniles may escape but their chances of survival are minimal if their mothers do not leave with them. Successful defence of cubs is usually only achieved when females gang together to ward off infanticidal males. Females whose cubs are in hiding are often prevented from going to them, resulting in the death through starvation of those cubs.

Larger male coalitions are more likely to kill all the cubs, including any born in the first few months after a pride takeover.

Infanticide is a necessary part of the lions’ reproductive success. The average interval between the birth of a litter and the next oestrus is 530 days, about the same as the average tenure of a pride male, however, the loss of cubs will prompt the lioness to start cycling and mate within a few days or weeks. Therefore, by killing any progeny found in the pride taken over, the male can ensure that he has the opportunity to reproduce his own genes during his tenure of the pride.

Following the successful takeover of a pride, and the loss of cubs, females enter a period of heightened sexual activity, mating more often and with more partners than usual, however they fail to conceive for an average of 134 days. The reason for this period of infertility is likely to be that it ensures that the males taking over the pride are able to hold it against other immigrant males and to increase the bond between the females and the new pride masters reducing the chance that the new males will desert the pride.

Activity

Lions spend 20 – 21 hours per day resting. They are most active in late afternoon when mothers suckle their cubs, and hunt mostly just after dark and in the middle of the night. Lions will become active at any time if an easy meal presents itself.

Lions can climb trees but due to their size and the angle of their claws this is an ungainly ascent and descent. Swimming is not an activity normally associated with cats, but some lions, such as those that live in the Okavango Delta, have come to terms with being wet in order to be able to traverse this flooded landscape. Some lions never appreciate water and appear scared of any expanse, taking great effort to not even get their feet wet when coming to drink. This preference appears to be locked in from an early age.

Self and social grooming are frequent activities with forepaws, chest and main being most frequently groomed.

Behaviours related to social maintenance include clawing, crouching, ducking, grunting, head rubbing, rolling onto back, scratching, snarling, stretching and tail flicking.