LionAid

ABOUT LIONS

Prides
Females define the pride and they usually stay within their natal pride for life. Sometimes, prides grow too big and then females will split off and set up new prides at the edges of their original pride territory. Within a pride females form loose associations that can change from day to day. Some females seem to enjoy periods of solitude, which can last for days to weeks at a time.

Relatedness among females
The females in a pride can be very closely related; mothers, daughters, and sisters, but equally some will be only be second or third cousins and some not related at all. This dilution in relatedness will be better understood when you look at males and reproduction. For the moment it is important to understand that the degree of relatedness among females in a pride may fluctuate significantly over each generation and therefore cannot account for co-operative behavior within the group.

How many lions are in a Pride?
A pride is composed of female lions that remain resident in their territory for most of their lives, adult males who have shorter tenures, and offspring of various ages. A pride can be as small as two females and their cubs and as large as eighteen adult females and their cubs. In our study area the largest prides have eight adult females and their young.

Pride males
A pride may have between two and seven adult males, and a group of males that join together is called a coalition (in the Okavango, we have never seen more than four males in a coalition - in our study area the average coalition size is two). Unrelated males may form coalitions. Females tolerate the presence of pride males in that the males defend their territory from incoming males and therefore ensure the best opportunity for the females to rear cubs to sub-adulthood.

Adult males aged six years and older are large enough and experienced enough to take over a pride and defend territory. They can remain with the pride until challenged by other males or might abandon the pride in favor of a neighboring pride with females who are reproductively receptive. In our study area we have two adult males who have taken over and run three prides over the last five years. Male lions will be discussed in greater detail under reproduction and the nomadic phase. A male lion leads a richly complex life and becoming a pride male is not the only reproductive option available to an adult male.

Females and cubs
Females first become pregnant when they are around four years old. For such a large animal they have a relatively short gestation, 110 days, and give birth to litters of between 1-5 cubs. The cubs are born tiny, defenseless, blind and unable to walk. Females about to give birth will leave other females in the pride and spend a few days looking for a den site, which is usually formed by dense vegetation. The cubs will remain in the den for at least six weeks and will feed only from their mother. Thereafter the cubs will be brought out to join the pride and lactating females will communally suckle. As with humans some females are more tolerant of their offspring than others.

Maternal care and lactation
Maternal care is a complex behavior under both genetic and environmental control. Among other things the hormones that play a key role in maternal care are prolactin and oxytocin, some females are very successful at lactating and show good maternal care, others are less successful and are quite intolerant of their off spring, as a result we see among lions similar inconstancies as among human mothers related to successful lactation or nuturant behavior. We aim to research differential levels of prolactin in the near future.

Equally, environmental pressures can influence maternal care: the presence of strange males in the area, poor nutrition and illness impose significant pressures on lactating females and can cause them to fail to produce enough milk or abandon their cubs.

Weaning and feeding growing cubs
Cubs are weaned between three to ten months; most commonly cubs are weaned by seven months. This differential is explained to some degree by the above. Our observations have shown that small groups of females tend to wean more quickly than larger groups. This may be because in a large group at least one or two females will tolerate long term suckling from all cubs. Lion are not very tolerant of their young at a kill and small cubs have to suck on what ever is left over. It is not uncommon to find seven to twelve month cubs looking a bit skinny from time to time if the adults in the pride are particularly ungenerous.

Females and older cubs/subadults
As the cubs grow up the adult females become increasingly supportive and caring. Young lions have a great deal to learn and as they mature they participant more and more in the life of the pride. Learning to hunt and learning how to use their territory being the most obvious lessons of all. By the time cubs reach two and a half the males are nearly as big as an adult female and yet have a long time to go before they are strong enough to take over a pride of their own. Our observations have shown us that one adult female usually ends up taking care of the sub-adult lions in a peripheral area of the pride territory, while the remaining females seek mating opportunities.

Nomads

The nomadic phase is probably the most challenging for any young lion. Once the young males have been pushed out of the pride they have to explore other territories and may encounter aggression from the resident males. During this time they must hunt alone and they are very successful at it. The fallacy that males are poor hunters springs from observations that they will dominate at female kills. Lions are highly opportunistic and a free meal is rarely turned down. Young nomads that encounter each other will form coalitions that may last a lifetime or may be temporary. In the early stages of the nomadic phase it is not uncommon to find mix sex groups but as the lions get older males stick together in preparation for pride take over.
Nomads will often live in the outskirts of a pride territory and this can cause them problems if they come near human settlements. Cattle and domestic animals are easy pickings and nomads are often killed by if they attack domestic animals. This is a highly contentious political issue and will not be discussed here.

We have observed older males who have been kicked out of a pride form new coalitions and undergo a second nomadic phase as fully-grown adults. Far from being lost souls struggling in the wilderness these experienced males do well and mate opportunistically with females they encounter. As we have said before being a pride males is not the only reproductive opportunity males have.

Males and females
Relationships between the adult male and female lions in a pride are complex. Remember that most females born to a pride remain life-long inhabitants of a territory, while adult males enter the pride from neighboring areas, contest for the resident females with then resident males, and if successful, begin mating with the females. Given that male tenure in a pride in our study area averages less than two years, an adult female might encounter up to five different resident coalitions as well as a number of nomadic adult males. In our experience, once new males have come into a pride and reproduced with the females, tension begins to increase. Soon after their cubs are born, female lions come back into estrus (like all cats), but because of the long-term dependence of their cubs, females are extremely reluctant to mate. By this we do not mean to imply the female understands the connection between mating and having cubs, but she will have experienced a five day mating during which time she will have been unable to hunt of drink, thus she is she will reluctant to mate while she has dependent cubs. They rebuff the advances of the males continually and aggressively, and after an average of about fourteen months, the males begin to get the picture, and start exploring neighboring territories for more amenable females.
We have observed females with cubs being mated and the consequences have been intriguing. Please see reproductive anomalies.

New males also exert considerable pressure on females that already have cubs from previous pride males (see also the Infanticide section). Females will take such cubs to the outer reaches of their pride territory to avoid the aggressive intentions of the new males, with the result that they might be forced to live in areas of low prey density. For example, the incursion of new males into the Santawani pride territory forced the females and their cubs into the eastern part of their territory – a range normally used during the wet season but largely devoid of prey during the dry season. The pride struggled to raise cubs as a result, and was ultimately unsuccessful. Rapid turnover among pride males can thus negatively influence reproduction in a pride.

Female reproduction
Females come into estrus on average every sixteen days. Estrus lasts between five and seven days. Like all cats lions are induced ovulators, in other words they need the stimulus of mating to release their eggs from their follicles. If a female is not mated when she is in estrus then the ripe eggs atrophy and sixteen days later when the next eggs are mature she will cycle again.

If the female is mated during her five day estrus and stimulated to ovulate she will then undergo a luteal phase. As the eggs leave the follicle cells on the follicle rapidly form a corpus luteum (yellow body) and secrete the pregnancy hormone (progesterone) for the next 55 days. A healthy female will be stimulated to ovulate by intensive mating and even if she is not fertilized she will undergo a luteal phase and not cycle again for 55 days. We have observed among out study lions that on occasion females that have been mated with return to estrus 16 days later thereby indicating ovulation has not taken place. We are currently researching anovulation as we suspect it may be caused by immunological pressure.

If she does conceive she will be pregnant for 110 days. During pregnancy lions, like domestic cats, maintain some follicular activity and have a short estrogen peak before they give birth as well as a post partum estrus. This is common among species that are induced ovulators. Like all cats lions start their estrus cycle again soon after giving birth. There is a degree of variation among females and some return more quickly than others.

Mating

Males can mate every twenty minutes for up to five days at a time. This is in fact major overkill and females can be stimulated to ovulate over a shorter period. Along with others we have observed that periods of intensive mating after new pride males have moved into the territory often fail to result in pregnancy. All that effort for so little return is puzzling unless we look at the female reproductive system. The first day of estrus serves three functions.
1- To finalize follicular maturation.
2- To stimulate cells in the vaginal and cervical area to be optimally responsive to mating.
3- To advertise a female’s readiness to mate. For to a male lion estrogen acts like Channel Number Five.
For a solitary female leopard this advertising period is critical and the male will hopefully find her within two to three days of her starting estrus. For the more social lion it turns out to be a handicap. If a male is with the female on her first day of estrus (and an incoming male is highly likely to be) and he starts mating her before she has had a chance to optimally sensitize her system then she will ovulate more sluggishly and most probably not for 48 hours after initial mating. By this time the male is shooting blanks. He may have stamina but he cannot maintain adequate sperm production. Thus conception is highly unlikely. Lions tend to conceive five to six months after the new males have moved in when they have relaxed their hold on the females therefore are less likely to be with them on their first day of estrus.

Given the opportunity a female will mate with multiple males during her estrus. We have observed one female mate with her two pride males and then with a pride male from a neighboring territory. She sadly did not produce cubs because it would have been interesting to see which male sired the cubs.

Reproductive anomalies
Since females come back into estrus soon after their cubs are born, they can then attract the unwelcome attention of the males. Unlike domestic cats that can freely mate again during this time, lion cubs are dependent for a much longer time on their mothers. While we do not believe that female lions are intelligent enough to associate mating with pregnancy, they are certainly capable of knowing that if they mate again while they have cubs, the males will keep them from their cubs for up to five days while they are mating. Females in large groups are safe because they can very effectively resist the advances of the males. Single females, however, can be “ambushed” and kept from returning to their cubs while they are “forced” to mate. We have seen such incidents with strange males who later accepted the cubs and interestingly we have seen the fathers of cubs in a den began mating again with females – in one case the cubs starved to death.

This brings up an important aspect of our work. We never interfere with the lions. We don’t treat their wounds, “save” their cubs, or provide food when they are starving. These are wild animals that are living their natural, if often difficult lives. We will only assist them if they have encountered something not natural to their environment, like if they are stuck in snares set by poachers, etc.

Infanticide
Infanticide refers to the killing of cubs by an adult. More often than not this is done by male lions but female neglect could also be considered indirect infanticide.

A male will kill cubs that he is confident he has not sired. This is not uncommon behavior but it needs to be explored. Males do NOT commit infanticide to bring females into estrus, because we have already seen that females return to regular estrus cycles soon after giving birth. This commonly held belief is based on the assumption that lactation suppresses estrogen. For a healthy well fed female this is rarely the case. For a more in-depth analysis of Lactational suppression please go to Research Results and look up Lion Reproduction.

When new males come into a territory and have never encountered the resident females before, they will try to kill any young cubs they can catch. They do this because they have a limited time with a pride, and cannot afford to “wait” while the females raise the cubs belonging to the previous males. But once again lion behavior is not cut and dried. Males will often carefully explore a territory before they take over and during this time they will mate with any female in estrus they encounter. This can include pregnant females who are experiencing their pre-partum estrus spikes, and females who have returned to estrus cycles after their cubs are born. We have recorded several cases where already pregnant females were mated and when the cubs were born a short time later, they were accepted by the new males as their own despite their true paternity. Similarly, we have seen cases where females were mated who already had cubs in a den, and these cubs were then later also fully accepted by the new males. In other situations, when new males arrive in a territory, females with dependent cubs will move to the edges of their territory to avoid the males and try to raise their cubs there. When these cubs have reached the age where they can care for themselves, the females will then come back into the core of their territory and mate with the new males. Infanticide is therefore not an automatic consequence of a pride takeover, as female lions have a variety of ways of protecting their cubs. A consequence of this is that a pride can contain cubs of very diverse paternity – those sired by the previous males, the new males, and even those sired by nomads.

Hunting

Past studies of hunting have shown that the only reliable way to determine exactly what lions eat is to follow them continuously during their active hunting periods. Such intensive monitoring is not possible in this study area, as forests, rivers, and other difficult terrain make it impossible follow lions with a vehicle. Also, the presence and noise of a vehicle, as well as lights needed to drive the vehicle at night, would greatly influence the ability of lions to catch prey. Consequently, we cannot provide estimates of prey consumption by a particular group of lions over time. However, by recording all prey items we either found the lions with or saw them catch, a relatively complete picture of prey consumption emerges, although we will underestimate the importance of small prey items as the lions consume these rapidly.

Our studies of prey consumption have focused on two major aspects: overall prey consumption by the study lions, and differences in prey consumption by two neighbouring prides (Santawani and Mogogelo prides). In terms of overall prey consumption, one significant result is the diversity of prey animals taken by the study lions. In other studies, 4 or 5 prey species made up 75% of the diet of the lions. In the Okavango, at least 7 prey species are needed to make up this total, and overall, the Okavango lions have been observed to take a total of 22 different prey types. This diversity of prey types is related to the seasonal availability of certain prey animals: for example, during the dry season, zebras, wildebeest, and buffalos are not within the Santawani pride territory, and the lions rely mainly on impalas, giraffes, tsessebes, kudus, and ostriches.

When prides are compared, some important differences in prey consumption become apparent. While all prey types are available to the Santawani and Mogogelo lions, there are significant differences in the numbers of giraffes, baboons, and warthogs taken by the different prides. This difference is best explained by experience. Lion cubs have a long period of dependence on females in the pride, and during this time, they gather a diversity of information and experience. Hunting techniques are different for many different prey types – lions approach and hunt buffalos very differently from zebras, impalas, and wildebeest, for example. If lions have not learned how to hunt particular prey items, such prey will not be taken despite their occurrence/abundance within the pride territory. The Mogogelo lions have learned how to efficiently kill baboons by chasing them up trees and then waiting underneath the trees until the baboons panic and jump down again! The Santawani lions have not learned this technique, and never eat baboons. However, the Santawani lions have learned how to effectively hunt adult giraffes, but the size and defences of these animals clearly intimidate the Mogogelo lions.