Cheetahs are difficult breeders, but Kuno death was avoidable: Here’s why

A landmark paper published in Science in 1983 submitted that all cheetahs are virtually twins or clones with extremely low genetic variation, which makes their future uncertain. Four decades on, not only are cheetahs around, they have been tasked with repopulating a lost habitat.

The cheetah’s longevity was probably never in doubt, given that the species has survived 12,000 years since the Late Pleistocene period when many large mammal species went extinct and the population of cheetahs fell drastically, leading to inbreeding and genetic inelasticity.

Today, habitat loss and conflict with livestock owners pose bigger threats to the cheetah’s future. Yet, its unique genetic profile has made breeding a perpetual struggle for one of the planet’s greatest survivors.

Mating in the wild

In the social structure of other cats such as tigers or leopards, a large male territory encompasses multiple female territories to ensure female fidelity. Among cheetahs, females roam multiple male territories, and fidelity is not demanded of either sex. In fact, polyandry — in which a female pairs with multiple males — guards against further genetic constriction of the species.

Adult female cheetahs are solitary but not territorial. They travel across large overlapping home ranges, ignoring one another. While roaming different male territories, a female mates with multiple males — preferably, unrelated males — within an oestrus cycle, leading to multiple paternities in the same litter. Since female ranges overlap, territorial males are also free to try their luck with different females as they pass by.

Generally, when a female cheetah goes into oestrus, she urinates at prominent spots to attract a mate. However, uninvited males will often confront a female to check if she is ready to mate — during such encounters, it is not uncommon for an aggressive male coalition to injure, sometimes mortally, a female that is not in heat.

Relatively few cheetah matings result in conception. Cheetah sperm has low density and very high (70%) deformity. Post-conception, disadvantageous gene variants can cause loss of foetuses. And only 5% of cheetah cubs survive to adulthood.

Behaviour in captivity

Things get worse when the species is confined.

Genetic variation her top priority, the female is turned off by loss of mating choice in captivity. Though held in royal menageries for centuries, there is no authenticated record of cheetahs breeding in captivity until 1956, when a cub was born in Philadelphia zoo. Even today, only one in five captive cheetahs, male or female, breed despite multiple interventions.

In 2018, researchers tested female interest in urine samples from male cheetahs of varying genetic relatedness. Offered scents from 17 males, 12 females showed more interest in the most distantly related males, irrespective of the testosterone concentration in male urine or age parity.

Female cheetahs come to oestrus throughout the year, but may not show signs that they are not looking to mate. On other occasions, they may not go into heat for several months.Also, females housed together tend to suppress ovulation until they get familiar.

Misreading oestrus is risky because giving a male cheetah access to a female not in heat can lead to serious injuries. The species anyway shows signs of stress in captivity.

What foxed the scientists for long is that the cats, in spite of the long odds, do breed regularly in the wild — until they realised that the solution lay in mimicking the species’ unique spatial and social orders in captivity.

Cheetah ‘lover’s lane’

In the wild, adult female cheetahs are solitary except when rearing cubs. And males, barring a few, roam in coalitions of brothers, half-brothers and, occasionally, unrelated males. The sexes rarely meet when not mating.

When zoos started housing male cheetahs together, not only were unrelated males accepted by siblings in their coalitions, their sperm quality also improved. In 2011, a study in a zoo in the UK documented the grooming of an unrelated male by a coalition of brothers over time, potentially helping him to breed.

Females, on the other hand, responded positively when left on their own in solitary enclosures away from the smell and sight of males. In this model, evolved in South Africa and the United States, a long pathway — dubbed lover’s lane — connects isolated male and female holding areas, and takes males to female enclosures when it is time to sniff and tell.

To find out if a female is indeed in heat, she is first shifted to an enclosure close to the males to induce oestrus. She is then taken away, and a male is allowed down lover’s lane to sniff her now-empty yard. The male can tell from the smell if she is in heat. If he tries to attract her with a typical barking sound, she is released to join him. If he does not bark, he goes back down lover’s lane.

The lesson for Kuno

The purpose of India’s Cheetah Project is to establish the African imports in the wild. But it also attempted captive breeding by simply putting the sexes together in an enclosure and leaving the outcome to chance.

Wild animals are unpredictable and no amount of caution guarantees total safety. Yet, given the knowledge-based innovations that have cut the risks in captive cheetah breeding across the world, there is little justification for bringing the animals together in confined conditions in the hope that they might mate.