Believe it or not, fish can count, too. According to one study, angelfish can tell the difference between larger and smaller amounts, and can count up to three. When they're in a new environment, angelfish tend to take cover by joining the largest possible group of nearby fish. Spanish researchers ran an experiment where angelfish were given a choice between schools consisting of larger and smaller numbers of fish. The angelfish were consistently able to choose the larger school as long as it was twice as large as the smaller one. When the groups varied less in size, the angelfish's choices were less consistent. In other tests, the researchers found that in certain conditions the fish were able to tell the difference between numbers as small as two and three. Angelfish are not an outlier. Besides chimps, horses, and dolphins, many other animals have shown an ability to distinguish between larger and smaller groupings. Rodents and pigeons are accomplished counters, and even salamanders have some mathematical skills. Which goes to show that at least some of the traits that we assume make humans unique such as counting are common to many living things. We humans may be able to do math at a higher level than other animals, but when it comes to the basic building blocks of working with numbers, we're more connected to the rest of the animal kingdom than we may believe.