The contribution of genetics to an animal’s personality is a fascinating topic. There are many anecdotal reports of personality differences among breeds. For instance, Siamese cats are oft described as demanding, extremely vocal, and outgoing with strangers. The Russian blue is characterized as quiet, gentle and withdrawn, while the Persian is described as lethargic, lazy and reserved. Cat experts, primarily breeders and cat show judges, are quick to point out, though, that there are large differences among individuals within a breed too.
There is also scientific evidence that individual variation in behavior may be related to the cat’s genetic makeup. Researchers in the UK scored kittens on “friendliness to people” and determined that paternity accounted for most of the variation. Kittens sired by friendly fathers were more likely to be sociable than kittens sired by reserved fathers. The researchers made sure the kittens never met their fathers, so genetic factors would have to be responsible for this effect. The friendliness of the mother had little impact on the kittens’ sociability. Realize that genes do not code for specific behavior patterns, so the influence is indirect. For instance, the father’s genes could produce a physical trait, such as growth rate or coat color that sways the nature of the kitten’s contact with people, which in turn, impacts sociability. It’s too bad that we almost never know a cat’s sire, else those people wanting a friendly cat could just make sure to select a kitten with an affable dad.
Another example of how genetics can indirectly influence behavior comes from research on genetically linked deafness. White cats, especially those with blue eyes, are often deaf because the gene involved in the production of the white coat color also induces unilateral or bilateral deafness. Deafness has a marked effect on behavior, with many owners describing these cats as “not terribly bright.” In addition, in some lines of blue-eyed white cats, the females are unusually timid.
Numerous experiments investigating feline development have demonstrated the influence of experience on individual characteristics. Early socialization greatly affects personality. Kittens raised in isolation from people or cats for the first seven months of life, were extremely timid in new environments and displayed exaggerated fear responses when restrained by people. Kittens handled regularly during the first 45 days of life approached novel objects and people more readily than non-handled kittens. Sociable kittens were handled more frequently, handled for longer periods of time, and handled by a greater number of people during the “socialization period” (4-12 weeks of age) than reserved and timid kittens.
Early nutrition is also an important factor in determining the personality of cats. Several studies have examined how malnourishment in the mother impacts kitten behavior. Kittens of malnourished mothers are developmentally delayed, learning-deficient, and more accident-prone during play. When separated from their mothers, the kittens of malnourished moms were less distressed than normal kittens. Some of the kittens of malnourished mothers showed exaggerated levels of fear and aggression toward other cats and people. Most of the behavioral abnormalities persisted into adulthood, despite the fact that the kittens received appropriate nutrition after weaning.