In Kenya “atypical” cheetah groups have been described. Cheetah cubs were seen accompanied by two or more adult females or by adult male and female. Years of documentation show that cheetah females live solitary life except for the time when raising cubs and males live solitary or in coalitions. Mothers usually spend 16-18 months with their litters; the age of cub’s independence being the timeframe in which cubs hunt for themselves successfully. After separation from the mother, littermates stay together for up to six months perfecting their hunting skills. When females reach sexual maturity at approximately the two years of age they leave their brothers and start their solitary life. Males remain together for the rest of their lives in groups called “coalitions”, which may consist of up to 5 individuals. If there was a single male in the litter, he usually stays alone after separation from his sister/sisters – but it has occasionally been noted that males from litters raised near each other can also form a coalition.
The process of family separation is unknown. What prevent females from staying together for the rest of their lives too? Observations made in the wild may help to understand it.
Behavior observed in Moscow Zoo (MZ) (Russia) show us that in captivity female cheetahs demonstrate higher degrees of social flexibility than the traditional (typical) model of the cheetah social organization suggests. When housed in pairs or groups of three, they were able to form alliances, characteristically similar to male coalitions, but differences include: 1) a male coalition is most frequently based on littermates, while a female coalition can be composed of unrelated females; 2) while males in the coalition compete for female in estrus, all females in coalition come to estrus simultaneously, and breed with male/males; 3) while males do not participate in raring of cubs, females in coalition may raise litters together and adopt cubs (Publication in press).
Female “coalition” similarities to the male coalitions:
1) synchronization of behavioral activity;
2) the ability to accept new unrelated members;
3) a low level of aggression and high level of affiliative interactions (social grooming, physical contact and joint rest).
Differences between male and female coalitions:
1) A male coalition is always based on littermates, while a female “coalition” can be composed of unrelated females;
2) Unlike males, females do not compete for the mating partner. Instead, all members of female coalition can mate with one partner. Therefore the reproductive success of females in a “coalition” increases.
Adopting a cub took place at the MZ twice in 1986–after its birth and at the age of 5 months. In the “coalition” of 3 females, two of them gave birth one day apart, and the third 5 days later. The last female didn’t feed the cub, she was transferred to a different location and female “coalition” member was given the opportunity to take in the newborn, which she began to feed with her cubs. A week later, the two female “coalition” members were combined, along with their litters, and raised all cubs together. At 1.5 months, the adopted cub named Diana was handed over to the “Cub Grounds”. After 3.5 months, she was returned to the group consisting of the female “coalition” (Mary and Nanga) and their cubs. Of the new members, Diana was accepted by Mary first, and by the rest of the group within 3 weeks.
At the age of 4 Diana was singled out from the group of females, and after a 2 year break, at 6 years old, she was again reunited with the 14 year old Mary as a pair which lasted until Mary’s death at the age of 15. Besides the usual display of affiliative behavior (grooming the head and neck for example), Diana constantly licked the areas affected by trophic ulcers on the outside of Mary’s thighs, which contributed to their healing. This example may indicate, firstly, that an age difference (in this case, 8 years) does not interfere with high level of affiliative interactions between females, and secondly, that females are able to remember friendly contact with one another and renew it two years later. At the same time, in male coalitions, it is known that their members recognize each other after a year of separation, but there is an age limit for integrating unrelated males; according to Caro, a newcomer should not be older than 20 months old. This is most likely due to the fact of male cheetahs’ territoriality.
Co-raising litters. Our experience has shown that synchronized births in a female “coalition” allows for the females to unite with their litters; thus, the adult females raise their litters together. The females Mary and Nanga were brought together for the first time in 1982 with their 7 month old cubs, and the adult cheetahs showed friendly behavior towards one another and towards each other’s cubs. The next union occurred in 1985 when Mary’s cubs were 9 days old and Mary’s were 2 days old and invoked this behavior in both females. This will be described in further detail.
Before birth, the females were separated; each of them was placed into 2 adjacent cages, fitted with wooden nest boxes (200x100x15 cm) without roof. The females gave birth 7 days apart; Nanga gave birth on April 25 and Mary on May 2. On May 2, 1985, hearing the sound of Mary’s newborn cubs, Nanga grew concerned and tried to get to them, but Mary did not respond feeding the cubs. The next day, Nanga tried again, and Mary began to nervously drag her litter around the cage. When Mary left the dwelling for walks, Nanga was able to meet the other’s cubs and immediately began to lick them. After Mary returned, both females engaged in mutual grooming while loudly purring, after which Mary again began to drag one of her cubs around. Nanga stood up and gently pushed Mary with her head, after which she put the cub down and lied down. After some time, the two females went to Nanga’s cubs, licked them together and then lied by their side. That same evening, after a joint walk, they were separated with their respective litter, and Nanga began to grow concerned and again tried to get to Mary, who also began to worry, leaving her cubs. The females were brought together and Nanga immediately began to feed the litter and Mary lied down next to her, both females loudly purring. At night, the females were divided, leaving each with their own litter.
On the morning of May 4,1985, the sliding doors between the cages were opened and the two swapped places—Nanga went towards Mary’s cubs and Mary towards Nanga’s remaining food. After a joint walk, Nanga fed Mary’s cubs and both females went to Nanga’s litter. Just as Nanga lied down to feed the cubs, Mary began to drag some of them around the cage. Nanga left the cubs, allowing Mary to feed them, and lied down on the adjacent nest box, purring. After the second walk, the females licked each other’s cubs, sat with them for a while, and, switching places then began feeding their own cubs. After the evening walk, Mary immediately started eating (the females were fed in separate cages), and Nanga immediately began crying for her, refusing to eat. Still, it was decided to keep the females separated for the night.
On May 5, 1985, the females alternately spent time with both litters, moving from one to the other, and on May 7, 1985, they brought the cubs to one cage and fed them together in a single nest box. While the females were on a walk, the staff moved the largest nest box (210x120x0.20cm) to one of Nanga’s cages and moved all of the cubs there, but the cubs immediately moved back. They were again carried back by the keepers and the females were let back in from the outside enclosure. Once the mothers lied down with the cubs, they calmed down. The females took turns feeding the young; they crawled from one mother to the other and slept in a general group. An attempt to divide the females caused anxiety in them and it was not attempted again.
On May 12, 1985, a clear difference regarding the relationship of the females to the young emerged: Mary spent more time on walks or would lie nearby while Nanga fed all the cubs or groomed them. She would go on walks, making sure the cubs were sleeping and there were no outsiders in their dwelling. Sometimes both females lied on one nest box opposite one another and fed at the same time, but more cubs were always observed around Nanga.
On May 23, 1985, the cubs obeyed the two females, responding to their calls; however, not all of the cubs obeyed Mary’s inviting calls trying to bring the cubs outside—the 2 week old cubs did not move as confidently as Nanga’s. Since the last ten days of May, Nanga fed more often, but on June 10, 1985, the cubs, after trying Mary’s nipples, went to Nanga and only went to her from that point on. Starting on June 1, 1985, the cubs ate meat on the bone and walked with the females in open enclosures.
Two adult females Mary and Nanga in Moscow Zoo (Russia) with their two litters in 1985 (left) and with their cubs (background) and adopted cub (foreground) in 1986 (right).
What environmental conditions support group living in cheetah females? In captivity animals regularly receive food; they are provided with shelter and are protected from natural enemies. Captive cheetah females demonstrate higher levels of sociality than in the wild where enemies (lions, hyenas and leopards) still their prey, kill cubs and even adult cheetahs. Predator conflict is a primary limiting factor to cheetah life expectancy – in the wild they rare reach the age of 11, while in captivity can live for up to 17-19 years.
In literature, there is information on groups of females gathering in different parts of Africa. In Namibia, for example, out of 102 adult females, 16% met in groups of two or more and 28% of litters were accompanied by more than one adult cheetah (McVittie, 1979); in Kenya, 21% of litters were accompanied by two, and 16% by three or more adult individuals (Graham, 1966); and in Tanzania (Serengeti), the largest group consisted of 9 individuals: 2 females and their cubs (Frame, 1980).
Moreover, observations in Botswana (Vandermey, 2005) suggest the possibility for reproduction in females living together. In one territory, four females were observed: one with cubs approximately 6 month old and a group of three 4-5 year old females. Ultrasound examination revealed that two of them were in different stages of pregnancy (Vandermey, 2005) and the genetic results confirmed that they were all related and most likely sisters (Boast L., personal communication). It is possible that they were all previously members of one group, which they left as they approached birth. This phenomenon may reflect the fact that, firstly, favorable conditions were created in Botswana to fully meets cheetah female needs regarding social contacts, and, secondly, the fact of reproduction in living together females.
There are lions, hyenas and leopards in those parts of Kenya where “atypical” cheetah groups have been recorded. Group living may be one of the cheetah’s survival strategies. Behavioral observation of the family separation process may help to answer this question.