Do you have a citation for that? As far as I understand it, the nature of animal sentience is a very widely debated subject.
If you define sentience to mean "the ability to feel or perceive," then a wide array of animals are sentient. Look at any pet cat or dog to see a display of feelings like fear, excitement, or curiosity.
If you take a more narrow definition of "being aware of one's own existence," I imagine you would still find a number of animals who fit into the category.
An African Grey Parrot, while learning colors, asked what color his feathers were. https://en.wikipedia.org/wiki/Alex_(parrot); I would imagine there is a strong likelihood that you would probably see similar levels of self-awareness from other animals if we had a better way of testing for it.
After all, there's nothing so special about Humans and Parrots in particular, is there?
If you define sentience to mean "the ability to feel or perceive," then a wide array of animals are sentient. Look at any pet cat or dog to see a display of feelings like fear, excitement, or curiosity.
If you take a more narrow definition of "being aware of one's own existence," I imagine you would still find a number of animals who fit into the category.
An African Grey Parrot, while learning colors, asked what color his feathers were. https://en.wikipedia.org/wiki/Alex_(parrot); I would imagine there is a strong likelihood that you would probably see similar levels of self-awareness from other animals if we had a better way of testing for it.
After all, there's nothing so special about Humans and Parrots in particular, is there?