A long time ago, the great-great-great ancestors of humans and our relatives began to invest heavily in eyes. Sure, we have other senses — hearing, taste, touch — but primates excel at sight. There are lots of hypotheses to explain why eyesight was so evolutionarily valuable, from finding food to reading faces. But whatever the reason, vision became dominant, while other senses were left to languish, including our sense of smell. Primate olfaction is thought to be so miserable that scientists diminutively refer to our noses as “microsmatic” as opposed to the “macrosmatic” noses of dogs or rodents.
But the more we study the noses of our kin, the more we realize how important scent is to primates. Our closest cousins — the monkeys and apes in the Haplorhini (which refers to the to dryness of our noses) — possess similar sniffers to us, but as you move away from our supposedly feeble-nared lineage, our relatives become better and better smellers. Our most distant primate cousins, the lemurs and other ‘wet-nosed’ primates (Strepsirrhini), have a heightened, almost un-primate-like sense of smell, and recently, scientists have come to appreciate just how much they may rely on information obtained by their noses.
Lemurs use scents to tell who’s who, mark territories, and send important signals about their health or social status. Lemur sex lives, especially, are very smelly. Lemurs can tell whether a given secretion comes from a male or a female, and if female, whether she’s ready to make babies. Forget putting a female lemur on birth control — males will smell the difference, and lose interest.
Now, scientists have discovered that not only does smell come into play before pregnancy, lemurs emit particular scents when they’re expecting. These pregnancy odors are so unique that they can even be used to distinguish if the baby-to-be is a boy or a girl. Continue reading “Smells Like A Boy: Lemurs May Use Scent of Mother to Determine Baby’s Sex”
