In 1990, there were no studies on animal personalities. In 2020, there were over 900 published studies on animal personality. It has been found that some species (e.g., dogs, chimpanzees and orcas) can also be distinguished on the basis of the Big Five personality characteristics reported in humans. The paper concludes that there are excellent arguments for granting some basic rights to some animal species but having a personality is not one of them.
Herzog, H. 2021. We know animals have personalities. Does that make them persons? Psychology Today Jun 21 https://www.psychologytoday.com/us/blog/animals-and-us/202106/we-know-animals-have-personalities-does-make-them-persons