Gerbils (Meriones unguiculatus) that had been taught to distinguish between pairs of odors using a T-maze were able to distinguish between gerbils and four other species of small rodents, between male and female gerbils, between two male gerbils, between the urines of these two males when they were diluted 1 part in up to 1000 parts water, and between water and urine that was diluted 1 part in 10 000 parts water.