If you are a San Diego Zoo member, you have already received your copy of June’s ZOONOOZ magazine. Our sun bears are highlighted this month, with sun bear dad Dibu on the cover! Flip through the pages, and you will see photos of Marcella and her offspring Palu and Pagi, and watch video of them, too!
Although we miss Pagi, who is reportedly doing well in her new home at the Oakland Zoo, life goes on in our Sun Bear Forest. Marcella and Palu are back out on exhibit, and you can see them daily (see Sun Bears: Up in the Air). Palu, in particular, seems very happy to be able to climb, explore, and stretch his limbs again. He’s still a growing boy, and very active.
We haven’t yet developed a plan for weaning Palu from his mother. Certainly he is of an appropriate age to be weaned, and obviously Pagi has already moved on to a new stage of independence. However, Palu’s situation is different from his sibling in that he is not yet slated to move to another facility. If we separate him now, he would remain at the San Diego Zoo in the near term, and that presents some challenges for us.
Those of you who have visited our Zoo know that we have a very robust population of bears. We are one of the few zoos in the world that has six species of bears exhibited: pandas, polars, brown, Andean, sloth, and sun bears. Bear Canyon is pretty full, and we don’t have any open, unused, bear-friendly exhibits to move Palu to. That means that once he is separated from his mother, he would remain at Sun Bear Forest, where he would need to rotate exhibit time with Marcella.
Rotating animals on exhibit is a common practice. It allows animals to have some time out in the larger open space of the public enclosure, where they get exercise and sunshine. It allows them time in the back, where they get some privacy and closer inspection by their keepers, important for observing changes in their health status or growth pattern. It keeps incompatible animals apart, important for non-social species or aggressive individuals.
Zoo-wide, there are a number of animals that share exhibit time with others via a rotation schedule. Our aged Manchurian brown bear, Blackie, recently began rotating with the younger grizzly bears to allow the youngsters more room to roam when on exhibit and ensure old Blackie gets plenty of peace and quiet behind the scenes (see Brown Bear Changes). Our giant pandas, solitary by nature, have long rotated through our two primary exhibits to allow the public to see all of our individual animals. Not since Hua Mei was dependent upon her mother have we had enough exhibits to house all of our pandas, so rotation has become a fact of life at the panda facility.
In Palu’s case, we have an even better option than rotation: delay weaning. In choosing this option for the time being, both bears get daily exercise during their time on exhibit. They also continue to enjoy each other’s companionship under this option. We are happy to note that, unlike Marcella’s first-born son Danum, Palu is not aggressive and demanding of his mother. The dynamic between them allows us to consider this option, whereas with other individuals it may not be possible to extend this relationship.
Further, at some zoo facilities in Europe, it is common practice not to wean young sun bears from their mothers, especially females, until they are of breeding age. In those cases, the young female is even introduced to a social relationship with her father, as the three bears are housed together when their personalities permit it. Thus, there is precedent for multiple generations of related bears being housed together in this species.
We need not be concerned that Palu will attempt to breed with his mother any time soon. We expect he will not reach sexual maturity for several more years. Long before then, we will have found a new home for him and weaning will take place. Or, a new male will have moved to San Diego to breed with Marcella, necessitating the removal of Palu from the social mix. Weaning will happen some day, but for now, mother and son will continue to remain a pair on exhibit. We hope you find them as interesting to watch as we do!
Suzanne Hall is a senior research technician for the San Diego Zoo’s Institute for Conservation Research.