Your Toronto Zoo is excited to announce the birth of two red panda cubs! Born on Thursday, June 13, the two cubs were delivered in a cozy nest box in the red panda house in a nest of bamboo created by mom Sakura. Wildlife Care staff is giving Sakura and the cubs time to bond without disturbance but is keeping a close eye on them via camera.
As the only red panda at your Toronto Zoo, how did Sakura become pregnant?
At nearly 11 years old, and after an unsuccessful breeding season last year, Sakura’s fertility was believed to be declining. Indeed, she arrived at your Toronto Zoo in “retirement” from the AZA Red Panda Species Survival Plan®. However, before Sakura’s arrival this past January she spent the first few weeks of the breeding season with her former mate, Arun. It seems they shared a passionate goodbye!
Because she had been housed with Arun, Toronto Zoo staff did their due diligence and collected fecal samples in February. Your Toronto Zoo’s Reproductive Science team, the only one of its kind in Canada, performed hormone analysis and in March, the initial results came in: Sakura had elevated fecal progesterone levels, indicating pregnancy was possible.
How did we confirm she was pregnant?
Pregnancy in red pandas is challenging to determine. After a successful breeding, a female’s body acts like she is pregnant (including physical, hormonal, and behavioural changes) whether or not she successfully conceived. The difficulties in diagnosing pregnancy vs. pseudopregnancy are compounded by delayed implantation, where a fertilized egg pauses before implanting into the uterus, remaining dormant until optimal body conditions are reached. The only way to confirm pregnancy is by ultrasound, which is generally not effective until close to the due date.
Sakura was previously trained to participate in voluntary ultrasound sessions, and her new Wildlife Care team began practicing for ongoing follow-ups. While regular ultrasounds began in April, it was not until June 4 that the first conclusive observation of fetal development was seen. The Veterinary team confirmed bone development and fetal heartbeats later that week, revealing two developing cubs. In recent weeks, Sakura was observed nest building and spending more time in her nest boxes - a preliminary sign of birth preparation. On the afternoon of June 13th, Wildlife Care staff watching the nestbox camera witnessed the arrival of the first cub at 1:15, with the second one following about 15 minutes later.
Challenges with red panda pregnancy and cubs
Red pandas are a difficult-to-breed species due to pre- and post-partum challenges with offspring survival. Evidence is showing a high percentage of early pregnancy loss in this species compared to others, with 40% of pregnancies being lost prior to birth as shown in a recent 10-year study by colleagues at Cincinnati Zoo. Red pandas have low rates of offspring survival both in the wild and in human care. Recent scientific studies have shown that as few as 40% of cubs reach their first birthday. These low survival rates have a significant impact on the growth of the red panda population under human care. Wild red panda cubs face similar mortality rates due to their vulnerable state at birth and ongoing threat illegal hunting and habitat loss. Safeguards have been put in place to try and minimize risk factors for these new cubs, but it will be some time before their future is secure. During this fragile developmental stage, Sakura and her cubs will not be visible in the red panda habitat.
How can we help this endangered species?
In April 2015, the conservation status of red pandas was elevated to Endangered by the International Union for Conservation and Nature (IUCN). Red pandas are elusive and challenging to study in the wild. Their population has been estimated by experts as anywhere between 2,500 and 10,000 individuals, but all agree that the species is declining - by as much as 50% in the past 20 years. Earlier this year, the Toronto Zoo Wildlife Conservancy committed to a long-term partnership with the Red Panda Network to support conservation projects in the wild ("in-situ"). To donate in support of red pandas, visit www.wildlifeconservancy.ca/donate.