Evolution Of Animal Personalities

Anyone who has ever had a close friendship with a pet can tell you that animals definitely have their own individual personality. Strangely, it is only very recently that the majority of scientists are beginning to acknowledge that animals differ strikingly in character and temperament. These studies have made it evident that individual personalities are a widespread occurrence in the animal kingdom, rather than an exclusive feature of human beings.

Definable personality differences have been described in more than 60 different species, including spiders, squids, primates, mice, birds, fish, insects and even mollusks.

Researchers at Santa Fe Institute are looking for an explanation for why animal personalities may have evolved. They say that personality, defined as consistent behavior over time and in different situations, is very poorly understood in animals. Currently, scientists aren’t sure exactly why different animal personality types exist within a single population.

According to classic Darwinism, one personality type should be more successful than another, and become the dominant personality, such as being aggressive rather than timid. However, what scientists are finding instead is that animal personalities vary as much within their species, as humans do.

Using a mathematical model, the researchers demonstrated that this fundamental trade-off can produce populations where some individuals put more emphasis on future reproduction than others, and therefore are more cautious. Conversely, individuals who put emphasis on current reproductive success, evolve a more risk-prone personality.

It is likely that further research will reveal more mechanisms behind animal personalities. Currently, these researchers are developing better ways of structuring properties of personalities.

Posted by Rebecca Sato

*The referenced study is titled Life-history trade-offs favour the evolution of animal personalities and can be found in the journal Nature.