14 DAY TRIAL // Authorities in northern Nigeria are extremely preoccupied with applying the Sharia, the Islamic law. They have even impeded an anti-polio vaccine campaign for fear of inducing sterility in the Islamic women. But meanwhile, Nigerian olive baboons seem to be indifferent to Sharia.
These monkeys which have been found in Nigeria's Gashaka-Gumti National Park sometimes ingest natural contraceptives that may turn the females less attractive to males and almost certainly decrease their chances of becoming pregnant. These are the results of the research made by a team led by James Higham of Roehampton University, UK, who discovered high levels of phyto-progestogens in the feces of female baboons at certain times of year.
Similarly to the synthetic progestogens employed in the pill, phyto-progestogens have a hormonal contraceptive effect imitating the action of the progesterone, a female sex hormone naturally synthesized by the female's body. The team discovered that levels of these progestogens boomed in females during the plum season.
From August to October, the baboons in the Gashaka-Gumti National Park area feed extensively on the progestogen-rich black plum Vitex doniana.
Like most female monkeys and apes, the baboon female has rumps called buttock pads (ischial callosities), a thick and brightly colored tissue around their genitalia. These organs are meant for sexual signaling. When a female is in estrus, the pads swell and redden and this is the signal a male needs to experience sexual arousal but also for reaching the female's fertility peak.
In a group of 13 Gashaka-Gumti baboon females, the more progestogen excreted, the less the females' callosities got pink sexual swelling, not attracting males' attention.
Primatologist Patricia Whitten of Emory University in Atlanta, Georgia, believes that it might benefit the baboons, which can breed year round, not to get pregnant in the plum season, as this is the wettest time of year, when disease is most easily spread.