“Our goal is not to have a lemur living alone.”

As the lemur gets older, its movements become slower and more rigid. They wobble over branches that they can easily grip. Sometimes their comb will drop their teeth, which is a set of teeth used for grooming, making it difficult for them to keep their fur fluffy on their own. So the best companion for an elderly lemur is another aging lemur, someone who does not want to get stuck but who is content with just sitting together and helping with grooming. “The little ones can be very troublemaker,” said Dr. Gharib.

To her credit, Cheyenne has never accepted any aging lemurs. After a while, the goalkeepers attempted to introduce Martin, an upside-down female lemur, to Cloris and Xian. Cloris didn’t mind – loyalty the cataract might have helped him. “She doesn’t care what anything looks like,” said Keith. But Cheyenne showed her teeth, stared at the new lemur and eventually knocked it out. Ms. Keith said Cheyenne could be bossy but Martin was notorious for divisions: “She was not showing proper feelings for Cheyenne.”

However, Cheyenne and Cloris are still open to elderly individuals joining the enclosure in Ward D. Until a few months ago, lemurs would coexist with PedroAn old mongoose lemur loved kiwi, until he died.

Wild lemur populations are often sympathetic, which means they live in the same geographical area. But scientists rarely notice the different species interacting with each other, according to Dr. Tecot. One A 2006 study It found that crested lemurs and Sanford lemurs of Madagascar formed a multi-species association, communicating and coordinating their activities over time. The pairing of lemurs of different species appears to be more rare, if it occurs at all. Dr Tecot, who co-managed the Ranomafana Red-Bellied Lemur project in Madagascar, has not seen any mixed-species pairs in the wild.

In captivity, these matings could provide insights into how lemurs form inter-species companions, according to Epic Kulahshi, a postdoctoral researcher at the University of Notre Dame.

Cheyenne and Cloris, who will turn 33 in April, don’t have the energy to play anymore. But they’re still soaking in the sun in their outdoor enclosure and staying warm in their sleeping baskets lined with woolen blankets to soothe their old bones.

In recent years, Ms. Keith said, Cloris has been going through more episodes of forgetfulness as she appears to be unaware of where she is – her bodyguards call her “the big moments”. But when Cloris returns to clarity, in her good eyes, she sees that she is still with Cheyenne.