Primate's scent speaks volumes about...(duke.edu/ ). The males have a gland...)

The males have a gland and spike on each wrist that is used to scratch and mark saplings with highly aromatic scents. A pair of glands on the shoulders "like misplaced nipples" manufacture squalene, a scent molecule that works like glue to keep the more aromatic compounds in place longer. Males can be seen dabbing the wrist gland on the chest gland and then scratch-marking. The wrist glands are also central to the "stink fighting" of ringtails, in which they rub the glands along the length of their bushy tails, and then foist them into each others' face to express dominance.

Most importantly, the male also has a scent gland on his scrotum that becomes critical to marking territory and advertising fitness during mating season. He does a handstand and rubs this gland directly onto a tree trunk to let any interested lemurs know who he is and what he's made of.

Scent not only speaks volumes, it's physiologically expensive to make, Drea said. When a lemur is ill or socially stressed, its scent changes dramatically. "If he loses his signals, it's quite likely its because he's less genetically fit," Drea said. "And his sexual or social partners can know that."

Female ringtailed lemurs have just one scent gland in the genital area, but their scent is more complex than the males'. Via scent, females may advertise not only their fertility, but the presence of a pregnancy and how far along it is, Drea said.

To a human, a lemur has a sort of musky scent. "In its little vial, the sample smells just terrible," said Charpentier, the postdoctoral fellow who deciphered the genetics and is now examining the behavioral response to these scents.

But under a gas chromatograph and mass spectrometer, postdoctoral fellow Boulet found that the powerful musk resolves into at least 203 different chemical compounds in a complex mix that has been found to vary not only by season, but by an individual's genetics as well.
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