Half of all the cubs born to African lions (Panthera leo) will die before they are 2 years old. Some will starve, others will fall prey to predators like hyenas, and infanticide will claim some 25 percent or more of the unfortunate cubs. Adaptations linked to their social lifestyle give the lions a better chance of protecting their young, and help them provide sufficient food in the grassy plains, scrub and open woodlands of sub-Saharan Africa.
Creches and Synchronized Reproduction
Lions live together in prides made up of a male, or a coalition of males, and females with their dependent young. Synchronized reproduction, where females come on heat at the same time, is common in lion prides. As the cubs are around the same age, they can be raised together in creches, in which the females help to look after the young, and will nurse cubs belonging to other lionesses. An important function of forming creches is to defend the cubs. If the pride is taken over by invading males, the invaders will attempt to kill young who are still suckling. The females will come back into estrus within a few weeks, and the invaders can father their own offspring. Females from nearby prides will also try to kill cubs -- a quarter of cubs are lost to infanticide. The bonds created in a creche cause mothers to defend all the cubs, not just hers; as a group they can be more successful at protecting the young.
Most female lions stay in the same pride as their mothers. Because all the females are related to each other -- mothers, daughters, aunts, sisters -- they share the same genes. This is another reason to collectively ensure the survival of all the cubs. Male coalitions are generally formed from pairs of brothers who have left their natal prides. They sometimes get together with half-siblings or cousins. So they share genes with the cubs, even if they are not parental, and this provides an incentive to protect all the cubs in the pride.
Mothers leave the pride to give birth in a secluded spot. The newborns' coats, covered with dark spots until they are about 3 months old, probably help to protect them, acting as camouflage as they hide amongst the undergrowth. The new cubs won't join the others until they are 5 to 6 weeks old. This may be because they feed only on milk during this period, and older cubs might prevent them getting enough. A study by Anne Pusey and Craig Packer from the University of Minnesota found that cubs under 2 months were easily supplanted by older ones when they were trying to suckle. Cubs older than 2 months didn't have this problem.
The Role of Males
Coalitions of males play a major role in protecting the cubs. If they can maintain control of their prides, preventing takeover by other males, the cubs are at a lower risk of being killed. A coalition with three or more males will usually keep control of their pride longer than a single male or pair, and this allows them to produce more offspring who are able to survive. While the females do most of the hunting, males are able to bring down prey too large for lionesses. An animal like a buffalo can feed the whole pride. The males take their share of the kill first, but they will make sure the cubs, who often arrive late, are able to feed from the carcass, as females will take meat from the cubs.
- National Geographic: Serengeti Lions
- San Diego Zoo Global: African Lion, Panthera Leo August 2005
- Animal Diversity Web: Panthera Leo Lion
- Mammal Anatomy: An Illustrated Guide; Marshall Cavendish Corporation
- University of Minnesota: Non-Offspring Nursing in Social Carnivores: Minimizing the Costs
- University of Minnesota College of Biological Sciences: Reproduction
- Anup Shah/Digital Vision/Getty Images