I was hoping to write a short update about how we reintroduced the big guy, greater one-horned rhino Bhopu, back into the exhibit to meet up with rhino mom Alta and her calf, Charlees, and how everything went as expected and there was no drama. But as a zookeeper, I should know better: we can’t count on anything to go as expected when working with animals!
We had waited a few months to let Alta and Charlees scope out the exhibit on their own. Bhopu, who has been by himself in the boma yard since Charlee’s birth, is lovable, but honestly, does a rhino mom really need that hulking body following her around the exhibit while trying to bond with her little one and getting her accustomed to her new female herd-mates: Asha, Tanaya, Sundari, and Kaya? (See post, Where Are Those Rhinos?) Once they had the lay of the land and seemed comfortable, we decided it was time to bring Bhopu back into the mix. But, there’s really nothing gradual to this process. It’s as simple as opening the boma door and watching what happens. Using the rest of the herd to our advantage, we strategically chose a range of dates that offered a distraction to Bhopu that was too good to resist and would keep him occupied for a few days: we set him up on a date!
We monitor the girls’ estrous cycles pretty accurately by submitting weekly fecal samples to our Endocrine Lab for hormone and pregnancy analysis. We expect to see them cycle every four to six weeks (see Collecting Rhino Treasures: Poop!). We really only had one candidate to set up with Bhopu: Asha, the nine-year-old. We believed she would cycle sometime around the end of June, and these behaviors and signals would help make Bhopu’s transition a little easier for Charlees. Greater one-horned rhino estrous behaviors can range from subdued and subtle to very obvious and last from a few hours to a few days. If we missed this opportunity, we would have to wait another month or so. We waited and watched Asha like a hawk, listening closely for a whistle vocalization, a sign of agitation, or just that indescribable characteristic that keepers are just in tune with – looking to see if she seems different than her usual self.
As I drove around the exhibit one morning at the end of June, I noticed one of the female rhinos alone, walking the perimeter of the exhibit. Hmm. Even with binoculars, I couldn’t identify the isolated rhino, but the girls are almost always paired up: Alta and Charlees, Asha and her sister, Kaya, and Tanaya and her younger sister, Sundari. When one of these girls is alone, it can only mean one thing: she’s in estrus. Ordinarily, this occurrence wouldn’t be a big deal, but today we had a very small window of opportunity that we had to take advantage of immediately!
We gathered the troops, conversed via radios and cell phones to concoct a plan, and made sure we had extra vehicles available. First, we conferred to make sure we were all in agreement that this was the best opportunity and possibly the only sign of behavioral estrous that we might see. We all agreed and quickly met up in the exhibit.
With our trucks in position, we opened the heavy boma yard door, and Bhopu calmly exited. A little while went by, and Bhopu wasn’t picking up on any of Asha’s signals. Instead, he searched the exhibit and met up with each rhino. As he approached Alta, we were poised, 4-wheel drive engaged, ready to intervene any potential aggressive interactions. Alta, the super-protective mom that she is, roared at Bhopu and took off with her calf. Among the confusion, Alta and Charlees were separated from each other for a little while. We maneuvered our trucks around the very bumpy exhibit terrain, bouncing around while trying to reunite these two. Instinctively, Charlees tucked herself into the rocks way in the back of the field exhibit. Alta only searched the front of the exhibit! We had to try to get her to walk in the direction of Charlees, while timing it perfectly to encourage Charlees out of her hiding spot so Alta could spot her. This strategy took some effort on our part, but very soon they were reunited, and we all felt like we were in the clear.
That was a tough, but memorable, day. Alta is a great mom and continues to keep a careful watch over the little one. Charlees has had several subsequent interactions with Bhopu, and he’s been quite gentle with her, probably because Alta just gives him a look and a snort, and he respects her protectiveness. Charlees is really doing well on exhibit with the rest of the group. She readily approaches the feed truck and sometimes she even visits with the guests on the Caravan Safari Tours.
Jonnie Capiro is a senior keeper at the San Diego Zoo Safari Park. Follow Jonnie’s tweets from the field on the Safari Park’s Twitter feed.