Because ants lack noses, they use olfactory receptors on their antennae to help them find food or sniff out potential mates. For the study, published Jan. 25 in the journal Proceedings of the Royal Society B: Biological Sciences(opens in new tab), scientists trained nearly three dozen silky ants (Formica fusca) to use these acute olfactory receptors for a different task: finding tumors.

— Read more in Ants can detect the scent of cancer in urine at LiveScience.

As forest-dwelling animals, they are small and secretive deer, and while their barking call is a handy indicator for humans looking to photograph muntjac, they do most of their interspecies communication through scent. On the faces of muntjac deer are two sets of scent glands; the preoribital which sits just in front of the eyes, and the frontal glands that sit on the forehead. While they’re not the only hoofed mammals to have these glands, they use them for communication more often even than other deer species that live in larger groups.

— Read more in Muntjac Deer Have Bizarre Flaring Scent Glands On Their Face at IFLScience.

But Donut, she says, likely has another trick up her furry leg that we humans don't use to tell time (or at least we don't realize we use): "That's olfaction," [Alexandra] Horowitz says. "Dogs are living in basically an olfactory world, and I think they are able to track time with smells."

—  Read more in Can dogs smell time? Just ask Donut the dog at NPR.