Friday, June 18, 2010

Free in the Forest - Duke Lemur Center's Free-range program

by David Haring, Registrar

It was an historic day at the Lemur Center: The release of the first group of lemurs from the new Releasable Building (now officially designated as Ata Ala) into the 6.5 acre NHE 8, one of the four Natural Habitat Enclosures which surround it. Animals released into the forests from Ata Aly will be able to roam freely all summer (and throughout the cooler months, during warm spells). It is fitting that the group chosen for the first release was led by the red-ruffed lemur matriarch Pyxis, who at 15 years of age, is a veteran of many months free ranging at the Lemur Center. Pyxis was born into NHE 6 before it was subdivided into four enclosures, so her habitat in NHE 8 has been home turf since infancy (although she has not free ranged here since 2007). For a detailed summary of Pyxis’ amazing life, please see my blog entry of May, 2009.

Surprisingly, when the gates of the RB were opened and Pyxis’s group (consisting of her mate Hunter; their triplets born in 2009, Esther, Phoebe and Orion Junior; and twins born in 2007, Scorpius and Aries) were released into the forest, it was not the indomitable Matriarch who boldly led the way into the wilderness, but the triplets, still not quite full grown, fairly gangly and really not very well coordinated (at least when it comes to navigation of an unknown and complex forest habitat). Perhaps Pyxis hung back so that she could witness and get a chuckle out of Phoebe and Orion Junior (OJ’s) hilarious first attempts at climbing trees. I have witnessed a fair amount of releases of na├»ve lemurs into forest environments new to them, but none have come even close to displaying the level of clumsiness shown by both OJ and Phoebe!

They had trouble climbing five foot tall saplings, of a size that could easily be mastered by the clumsiest of human children. They seemed to keep getting tangled up in the mass of branches that have a tendency to grow on healthy saplings (admittedly very unlike the branches of their home cages), and several times fell out of trees that were three or four feet high, disgraceful behavior for an arboreal primate! After a few minutes, the adults (Pyxis, Hunter, Sorpius and Aries), perhaps bored with this display of ineptitude from the younger ones, or perhaps eager to show them how the arboreal lifestyle is accomplished, took to the trees, scaling the highest tulip poplars with relative ease, (although Scorpius and Aries had only a few months experience free ranging in NHE 6 two years ago, it obviously made a big difference!). Surprisingly one of the triplets, Esther, seemed fairly competent in her first ever ascent of a real tree and could actually just about keep up with the group.

Alas, OJ and Phoebe were a different story. When they had finally mastered, to a certain extent, the art of climbing six foot saplings, they proceeded full steam to the next giant step: scaling huge pine trees (the type that have zero branches for the first forty feet). With each attempt the overly ambitious youngsters succeeded only in ascending a few feet up the scaly shear vertical wooden columns, before quickly losing their momentum, then their grips and then plummeting back to the ground in a hail of scraped off pine bark. Finally, they abandoned the pines, and figured out how to climb a reasonably sized hardwood tree (they really do learn fast!), which took them up to a level near the more experiences older animals. Here they were faced with learning another of the basic rules facing every free ranging lemur: not to jump on or walk out onto an obviously dead and rotten branch. Arboreal primates are amazingly adept at being able to quickly brush off falls that would seriously injure a person, but it is little wonder that by the afternoon of the first day free ranging, Orion Junior was cowering inside his cozy air-conditioned RB room, while the rest of the group continued to frolic in the forest.

Amazingly the incompetent yearlings made it through their first free range days in fine shape, and their confidence and ability have increased daily since then. Now the whole group can be seen in the treetops together exploring their enclosure. And, once again, after an absence of two years, the wonderful raucous cry of the ruffed lemur can be heard from the Lemur Center parking lot greeting visitors and letting them know that they have entered the world of the lemur. Everyone on the Lemur Center staff is also delighted to learn that despite the group’s increasing confidence in traveling through the forest, in which they are daily becoming more and more like a wild group of ruffed lemurs, the animals have continued to respond to their audible training cues, coming down from the trees on command, obediently following their technician’s training cues into the RB for conditioning lock up and feeding.

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