Around 15 years ago, I created a Facebook page for my cat, Sandi. Friends thought it was weird. Today, social media accounts for cats attract millions of followers, cats travel in backpacks and prams, and surveys consistently show that the overwhelming majority of owners regard their pets as family.
I’ve previously written about how cats became domesticated. But domestication isn’t necessarily a process with an endpoint. Could it still be continuing today?
Examples from wildlife suggest that adaptation to living alongside people can continue long after animals first encounter humans.
Research led by biologist Kevin Parsons at the University of Glasgow provides one of the clearest examples of this process. In 2020, Parsons and his team compared the skulls of urban and rural red foxes from London and the surrounding countryside, and found consistent differences between the two populations.
Urban foxes had shorter, broader snouts and smaller braincases – the rounded part of the skull that encloses the brain. These are changes that often accompany domestication. The researchers suggest that city life may favour foxes that are less fearful of people and better at exploiting food and shelter provided by humans.
A similar story is emerging in Dublin’s Phoenix Park. In 2022, ecologists Laura Griffin, Simone Ciuti and colleagues at University College Dublin found that, while some fallow deer living at the edge of the city rarely came near humans, others consistently approached people for food. Around a quarter of the population were “consistent beggars”, and these bolder females produced heavier fawns – suggesting that animals willing to approach people may be at an advantage.
These studies show that living alongside humans can drive evolutionary change in wild and semi-domesticated species.
But does the same apply to cats, a species domesticated thousands of years ago? There are two possible answers. Cats may still be changing – or perhaps cats have not changed much, and it is our relationship with them that has.
Let’s start with the cats.
Compared with dogs, cats have traditionally been viewed as “less” domesticated. Dogs were bred to work alongside us – herding livestock, guarding homes and helping with hunting – while cats largely domesticated themselves.
Drawn to the rodents attracted by early farming settlements, cats chose to live near people because it suited them, not because we selectively bred them for particular jobs.
One reason cats have been so successful is their flexibility. Unlike many species, they can adjust their behaviour to suit the environment they live in.
Where food is scarce, cats tend to live alone and defend their own territory. But where food is plentiful, such as around people, they can tolerate one another and form stable social groups. In fact, some researchers suggest that cats first evolved to tolerate other cats living nearby, before extending that tolerance to humans.
Although genetics plays a role, kittens that have frequent positive interactions with humans during a critical period (between around two and seven weeks of age) are far more likely to grow into confident, friendly adults.
This suggests cats have long had the capacity to form close relationships with people when the conditions are right. Rather than becoming fundamentally different animals, they may simply be expressing a capacity they have long possessed. If so, the biggest change may not have been in cats, but in us.
People’s changing needs
Over the past century, many people’s way of life has changed significantly. Across much of the world, fertility rates have fallen dramatically, from almost five children per woman in 1950 to just over two today. People are having fewer children, delaying parenthood, living alone for longer, and increasingly relying on companion animals to meet needs once fulfilled by close family relationships.
These demographic shifts have changed not only how families are structured, but also who, or what, occupies the centre of family life.
In Finland, a country that has experienced many of these demographic shifts, a 2023 survey of 857 pet owners found that, when speaking with family and friends, people without children were more likely than parents to refer to themselves as “mom” or “dad” in relation to their pets. They were also more likely to describe their companion animals as kids, children or family members, and reported stronger emotional attachment to them.
As more people delay parenthood or remain child-free, this way of relating to companion animals may become increasingly common. This shift may also be reflected in the growing popularity of cat breeds such as the ragdoll, valued for their affectionate and docile nature.
Ragdoll cats are known for their affectionate nature. xixicatphotos/Shutterstock
Changing attitudes have transformed the lives cats now lead. A species once valued primarily for controlling rodents is now just as likely to have health insurance, see a behaviourist and eat a specialist diet.
None of this means cats have stopped evolving. Living alongside humans could still shape their behaviour over many generations. But the evidence suggests that the more dramatic transformation has been in their owners.
We have changed what cats mean to us and, by doing so, changed the lives they now lead. Back when I created a Facebook page for Sandi, people thought it was eccentric. Today, it seems many more people have come round to my way of thinking.
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