Smells plays an important role in elephant lives. Elephants use their sense of smell to avoid predators -- in one study, the animals knew to avoid the smell of Maasai men (who, historically, hunt elephants) but not Kemba men (who do not). Scents are also a key factor in their decision-making processes, as elephants use sniff tests, for example, to discern if buckets are empty or full of food. And elephants are odorific communicators -- a young male Asian elephant has a sweet honey scent, whereas a sexually mature male "smells like a thousand male goats in a pen," one researcher told Nature.
"Apparently, an elephant's nose is not only long but also superior," says study author Yoshihito Niimura. Elephants have about 2,000 genes in their "olfactory repertoire," twice as many as dogs and five times as many as humans. (Our primate relatives scored low on the scale of smelling genes, too.)
By analyzing genes across species, Niimura says, we can deepen "our understanding of the sense of smell in humans." But smelling water from miles away? We'll have to leave that to the elephants.