Sun bears Palu and Marcella.
It has been some time since sun bear Pagi left us to travel north to her new home (see Overseeing Bears: The SSP) . Our staff has maintained regular contact with the keepers in her new home, and all reports are that she is thriving there. After initially developing a relationship with her older sister, Bulan, it appears that the young girls have had a falling out. No matter, as Pagi is happy interacting with her keepers and continues to enjoy training opportunities with them.
Palu is still with his mother, living comfortably on the Sun Bear Trail in the San Diego Zoo’s Asian Passage zone. Despite Palu’s continued presence, Marcella is probably not supporting his nutritional needs significantly; nursing is still seen, though rarely. Palu is a big, growing boy—he is heavier than his mother by several kilos—and his calories come primarily from food provisioned by keepers. Since the time of maternal dependence is ending, Marcella’s body is returning to its not-so-maternal baseline state.
As a result of this, Marcella has recently shown us some signs that she may have had a mild estrus. Her behavior changed, and she became more solicitous with Palu. For his part, the young male seemed confused by these changes, but it got us thinking that it’s time to separate these two animals before Marcella has a solid, fertile estrus. We don’t think it is very likely that Palu is reproductively mature yet, at age two, but we can’t be certain that he isn’t capable of fathering his own offspring.
Marcella typically cycles every three to five months. This is actually a pretty active estrus schedule for a Bornean sun bear in North America. Some females don’t cycle at all, and many cycle only once per year. Even with more frequent estruses, we can predict a quiet period for Marcella until sometime in the spring. During this lull, we will need to arrange for our big little bear to wean.
Marcella and Palu will settle into separate lives in the next few months. Keep an eye on Sun Bear Trail, as there will be some interesting bear behavior there in the near future.
Suzanne Hall is a senior research technician for the San Diego Zoo Institute for Conservation Research Read her previous post, 300 Pandas.
I saw Marcella in her exhibit with a male today. Is that still her son Palu? Or have you brought in a potential mate for her? Do tell…
Suzanne responds: Palu is still with his mother but will be separated soon.