Counting monkeys, fish, birds, and insects: Yes, they can!
> Rhesus monkeys chose sets with more geometric shapes just about as often as college students.
> Red-backed salamanders that headed for tubes with more flies.
> Mosquitofish that sought out groups with more potential mates.
> Honeybees that picked paths labeled with more geometric shapes that led them to sugar.
> American coot chicks that opted for larger groups of objects representing strength in numbers, rather than less.
Most of the studies found animals did a better job of judging the difference between numbers of smaller amounts (one vs. two, two vs. three) and when the difference was larger (eight vs. 16, 10 vs. 20).
The studies appeared in the publications Current Opinion in Neurobiology and Animal Cognition.