Helping a tiger become a Mom, using assisted reproductive therapy

Posted on March 10

Calgary, AB – Last week, the Calgary Zoo’s beloved Amur tigers, Youri and Sarma, participated in assisted reproductive therapy.

“Everything we do at the Calgary Zoo is with a focus to support wildlife conservation” said Jamie Dorgan, Director of Animal Care and Health. “Sarma and Youri are genetically significant animals within the global Amur tiger population. Supporting them to successfully produce offspring is critical for the international efforts to save wild Amur tigers from extinction.”

Sarma (9 years old) joined the Calgary Zoo family in August 2017 from the Cherrybrook Zoo. Youri (7 years old) joined us in June 2018 from the Granby Zoo. Sarma and Youri are a recommended breeding pair by the Association of Zoos and Aquariums’ Species Survival Plan (SSP), but they haven’t successfully bred since they have been together. Both tigers are genetically valuable and their genes have not yet been represented, so the Tiger SSP requested we try artificial insemination with the pair. 

The Association of Zoos and Aquariums’ Amur tiger Species Survival Plan (SSP) contributes to the success of an assurance population of animal ambassadors in human care that advocate for their wild relatives, and inspire people to support important conservation efforts. Some SSPs already contribute to bolstering numbers or genetics of wild populations, and many more could in the future.

Female tigers are induced-ovulators, which means the act of mating has previously been the only way for the female to release an egg for fertilization. Breakthroughs in reproductive science have shown that with the use of hormone therapy to induce ovulation and assisted reproductive techniques, artificial insemination has a higher margin of success than it used to.

Reproductive physiologists for the Amur tiger SSP were consulted leading up to the procedure. In preparation for it, Sarma was given oral hormone therapy for a month leading up to the procedure to adjust her reproductive cycle. In the days before her procedure, she received a series of voluntary injections to stimulate her to ovulate.

Last week, our Animal Care and Health team harvested semen from Youri, confirming his sperm concentration and motility was good. As Youri was recovering in his bedroom, we anesthetized Sarma in her bedroom. Once properly positioned, Sarma was inseminated with the collected and extended semen from Youri. Sarma was kept with her hips in an elevated position for 30 minutes after insemination. Both Amur tigers recovered smoothly from their anesthesia. 

What’s next?
Sarma’s caregivers have collected baseline fecal samples before the procedure that will help confirm whether or not she’s pregnant in the weeks following the procedure. In addition to comparing her baseline hormone levels in fecal samples to new fecal samples collected over the 12 weeks, they’ll monitor for physical changes such as weight gain and mammary changes, and for behaviors such as nesting. If the procedure was successful, the fertilized eggs will now have implanted in her uterus, where cubs will develop over a three-and-a-half-month gestation period.

About Amur tigers
Amur tigers, previously known as Siberian Tigers, are classified as Endangered by the IUCN Red List with an estimated 540 individuals left in the wild. The species is mainly threatened by habitat loss due to agriculture, logging and mining. They are also illegally poached for the wildlife pet trade and for their fur and body parts.