Giant pandas Kai Kai and Jia Jia have officially crossed their first mating season, said Wildlife Reserves Singapore (WRS) in a media release on Tuesday (Apr 21).
The pubescent pandas were suitable for pairing last year but did not show signs of readiness to mate, it said. Pandas’ mating instincts are brought on by hormonal changes in response to seasonal variations, such as temperature changes and increasing day length from winter to spring.
"Kai Kai and Jia Jia’s development has been an interesting case for researchers as they are the first pair of giant pandas living so close to the equator," stated WRS.
To encourage mating, River Safari’s keepers and vets have employed a number of measures since last November to trigger the breeding cycles of the pandas. These included varying the daylight hours and temperature in the panda exhibit to simulate the transition from winter to spring in the pandas’ homeland in Sichuan, China, it added.
The pandas responded to the measures, with seven-year-old Kai Kai bleating and scent-marking more frequently to attract six-year-old Jia Jia, which "showed the first signs of coming into estrous" on Apr 5, marked by her swollen genital, restless behaviour and hormonal analysis that indicated she was in heat, WRS said.
Both pandas were brought together for the first time in their dens for natural mating on the evening of Apr 17. The 40-minute session did not appear to be successful and, as such, a decision was made to carry out artificial insemination to increase Jia Jia’s chances of conceiving.
Dr Serena Oh, Assistant Director of Veterinary Services, Wildlife Reserves Singapore, said: “Panda reproduction is a notoriously complex process, with females ovulating once a year, in which they are fertile for only 24 to 36 hours. Jia Jia’s hormones started falling on Friday and we needed to move quickly to artificial insemination due to the short window when female pandas are able to conceive.”
“In the next few months, we will continue to monitor Jia Jia’s hormone levels and conduct ultrasounds to determine if she is pregnant. We will wait and hope for the best,” she added.