What cats live in groups?
Domestic and feral cats sometimes live in groups and the lion, a big cat, always lives in groups. These are the only two cat species who live in groups.

Feral cat colony feeding. The food resource is the reason for grouping. Photo courtesy Robert Smith
Domestic and feral cats
Domestic cats often live solitary lives and they’re considered to be solitary animals but they can live in groups around a food resource and become sociable animals. I’m mainly referring to semi-domesticated feral cats normally under TNR programs or informal groups of community cats were food sources are consistently available. In these groups, the females compete for food and safe areas to rear their young while the males compete for access to the females. It’s a social system controlled largely by the predictability of the food supply and its quantity. The timing of females going into heat is also a factor. The females support each other in rearing their kittens.

Feeding a colony. Photo: Jenny Celebi.
Domestic cats in multi-cat homes also live in groups satisfactorily, a lot of the time. It’s a forced situation but domestic cats are adaptable and we see thousands of photographs of domestic cats living in groups in happy homes although there is always a potential for antagonism between individuals because of the innate character of the independent-minded domestic cat.
To conclude, food is a key factor in promoting group living for domestic, stray and feral cats. TNR programs support managed feral cat groups. These cats are not genuinely feral because lots of them are semi-domesticated. Volunteers feed the cats and trap and neuter them. They also check on their health and vaccinate them under some programs. But they are evidence that domestic and semi-domestic feral cats can and do live in groups when the circumstances are right. Although all the documented cases of domestic cats living in groups occur around artificial food sources.

Semi-feral cat colony. Photo: in public domain
Lions
I don’t think I need to discuss this in much detail because all the world knows that lions living prides i.e. groups, and they are the only big cat who does this. The social system of lions is different to that of other wild cat species. In other wild cat species the social organisation consists of a male range that overlaps the ranges of several females. In lion prides such as in the Gir Forest of India (Asiatic lion) males and females lead separate lives and associate during mating and at large hunts. The prides are made up of related females, their young and subadult male offspring. The average number of adult females in a pride is between 4 and 5 (within the range 1-11). The males make up coalitions of 2-6 individuals.

Lions including a group (pride) 2 white lions, asleep on the road in Kruger NP.
In the Serengeti of Africa a pride is made up of 2-18 adult females, their cubs, and 1-7 males. All the females are related and are the core of the pride which is made up of sisters, daughters, cousins and aunts. The females do most of the hunting and killing but the males displace females and their cubs at kills.

Pride of lions. Photo: Mandy on Flickr
My thanks to the best book on the Wildcats to help me through this article: Wildcats of the World by Mel and Fiona Sunquist.