A tantalizing solution was to take advantage of the 100 or more captive black lion tamarins in zoos and primate centers. Their genetic diversity could replenish inbred populations in the wild, but how would the researchers get the genes of the captive animals into the wild? Putting into the wild animals adapted over generations to being fed and protected at zoos would be both cruel and ineffective.
Leave it to the Brazilians to provide a solution at once creative and romantic: Padua and Martins captured two wild young female adults from Morro do Diabo State Park, which with over 800 animals has the largest tamarin population, and introduced them to three captive-born adult males brought from the Jersey Zoo in England and the primate center in Rio de Janeiro. After three-week honeymoons, the animals were then set free in the Morro do Diabo forests. The mixed-marriage couples together faced the challenges of finding food and shelter, establishing a territory, and reproducing.
They got along well enough—at first. The researchers observed the animals copulating, although no births resulted. After three and a half months, the first captive-born male was eaten by an ocelot, the second one was preyed upon after five months, and the last one disappeared after seven months. It seemed that the imported males could learn how to find food and shelter from their native partners, but not how to avoid predators. They all died before they were able to reproduce successfully in the wild.
Perhaps the captive males should have merely honeymooned with the local females and skipped the partnership in the wild. The next rescue operation that Padua envisioned would be to capture whole families, separate the adult females, and entice them to have a sexual dalliance with exotic males from the Jersey Zoo and the primate center in Rio. In the meantime, to ensure that they didn't find other partners, each wild-male mate would have to cool his heels in captivity. Then each female, once pregnant, would rejoin her native family to settle down once again with Mr. Wild-Born Right—if, that is, he would have her.
Martins and Padua were making plans for such encounters when a more urgent—and happy—need arose. When several new populations of black lion tamarins were discovered in central São Paulo State, Padua and his team realized they needed to concentrate on saving the newly discovered populations, totaling about 100 individuals, because they were all living in precarious situations. This short-term crisis is taking precedence, but the longer-term crisis of inbreeding will require attention too.
The good news is that researchers have learned that moving the tamarins into new habitats can work, but that introductions of captive animals into the wild do not. This information will help when researchers try once again to introduce new blood into the tamarin population.
The techniques for saving species in the wild vary. Species with less stringent habitat requirements, like the Arabian oryx in Oman and the white rhinos in South Africa, have been rescued by moving animals into new settings as well as outlawing their killing. In the United States, wild turkeys are rebounding because of hunting bans and because forest cover is expanding across the Northeast. More challenging to preserve are species that require a lot of land, like elephants, and species that have highly specific requirements for habitat and prey—and a poor public image—like black-footed ferrets.
Ultimately, as in all challenges, knowledge is power. Armed with the numbers and the distribution of a species, as well as a thorough understanding of the conditions it needs in order to thrive and reproduce successfully, we can, with enough resources, intervene to save wild species from extinction.