Two North American Zoos Unite to Save Amur Tiger by Cross-Fostering with Sumatran Tiger Family


(Oklahoma City, OK) – July 24, 2017 --- On Friday, July 21, the Oklahoma City Zoo and Botanical Garden received a female Amur tiger cub born at Philadelphia Zoo named Zoya, meaning “life” in Russian.  The Oklahoma City Zoo staff,  working closely with Philadelphia Zoo staff, has integrated the cub with a litter of three Sumatran tiger cubs born here two weeks ago and is seeing early signs of success.


Zoya, born on Monday July 10, is the first offspring of 10-year-old mother Koosaka and 9-year-old male Grom. Koosaka gave birth to five cubs, a large litter for tigers.  Two were stillborn, a third was accidentally injured by Koosaka and did not survive and a fourth developed a critical gastro intestinal issue that proved fatal even with medical intervention by Philadelphia Zoo veterinarians.


Zoya was not nurtured by Koosaka whose lack of maternal behavior is not uncommon among first-time mother tigers who sometimes neglect or reject cubs.  As a result, Philadelphia Zoo’s animal care team bottle-fed and continuously cared for the cub who continued to do well, gaining weight from about 2 pounds at birth to almost 4 pounds at 10 days old. However, the Philadelphia Zoo’s animal care team was concerned about hand-rearing a single cub without social opportunities with either a mother or littermates. “With this single cub, we knew that the best scenario for her was to find an opportunity for her to grow up with other tigers,” said Dr. Andy Baker, Philadelphia Zoo’s Chief Operating Officer.


In discussions with colleagues involved in the Tiger Species Survival Plan of the Association of Zoos and Aquariums (AZA), the Oklahoma City Zoo offered to attempt to integrate the Philadelphia Zoo cub with their litter. The Oklahoma City Zoo had a litter of three Sumatran tiger cubs born just one day before the Philadelphia Zoo litter, and their female, six-year-old Lola is caring well for her cubs.


After consultation between Philadelphia Zoo, the Oklahoma City Zoo and with other AZA colleagues, the teams decided the best option for the cub to grow up in a good social environment was for the Oklahoma City Zoo to attempt to cross-foster Zoya with Lola and her cubs.


Cross-fostering is the process of removing offspring from one mother and transferring them to another lactating mother with offspring of the same approximate age.  “Cross-fostering in tigers is unusual, but with less than 500 Amur tigers in the wild, every cub is important for the species’ survival,” said Dr. Rebecca Snyder, curator of conservation and science, Oklahoma City Zoo.  In 2011, the Oklahoma City Zoo successfully cross-fostered a litter of endangered African painted dogs with a golden retriever who had recently given birth.  Cross-fostering among tigers is rare with only a few cases having ever been attempted and documented.


After a 20-hour non-stop drive from Philadelphia, a team of four animal caretakers from Philadelphia Zoo arrived early Friday morning at the Oklahoma City Zoo with Zoya.  Upon their arrival, the Oklahoma City Zoo veterinary team examined Zoya while conferring with the Philadelphia Zoo team regarding the cub’s introduction into the Sumatran tiger litter.


“Though Sumatran and Amur or Siberian tigers are different subspecies, they look almost identical as cubs,” said Eddie Witte, curator of carnivores at the Oklahoma City Zoo.  “Our first step in cross-fostering Zoya is to add her into our litter of three cubs and cover her with the scent of the other cubs by rubbing her with hay from the den, tiger cub urine and even the other cubs. By doing this, we hope Lola will identify Zoya as one of her own.”


While Lola temporarily left her cubs for a feeding, the Oklahoma City Zoo animal care team entered the tiger cub den and prepped Zoya and the other cubs.  As part of this process the zoo team weighed each cub and confirmed that all three Sumatran cubs were male.   Meanwhile, Philadelphia and Oklahoma City Zoo animal teams gathered in the Joan Kirkpatrick Animal Hospital’s conference room to watch live video from the tiger’s habitat broadcast on a large screen monitor.  Everyone watched intently as Lola returned to her cubs and stood over the new cub Zoya. Within seconds, Lola began to lick and nuzzle Zoya to the great relief of the collective team.


True success for cross-fostering of a young tiger cub like Zoya happens when she begins to nurse from Lola.  After more than a week of being bottle fed by Philadelphia Zoo’s animal team, Zoya would need to learn to nurse from a tiger for the first time.  Both Philadelphia Zoo and Oklahoma City Zoo teams established round the clock monitoring of Lola and the cubs to confirm nursing behavior. After a brief nursing session on Friday night, the collective animal care teams were ecstatic to witness long nursing sessions early Saturday afternoon, Saturday night and another on Sunday.  During a brief Sunday morning exam, the Oklahoma City Zoo team confirmed that Zoya was gaining weight. With Zoya having established a steady nursing pattern with Lola, the Philadelphia Zoo team departed Oklahoma City early Monday morning.


“We are very happy that Zoya has integrated well with her new adoptive family,” said Donna Evernham, curator of carnivores and ungulates, Philadelphia Zoo. “She has made an incredible

journey in her first two weeks of life and our Philadelphia Zoo team is thrilled to partner with the Oklahoma City Zoo to ensure Zoya’s well-being. With fewer than 500 Amur tigers left in the wild Zoya’s birth is significant to the entire population.”


“We are privileged to assist Philadelphia Zoo with this unique situation and understand how crucial this cross-fostering scenario is for Zoya’s survival and long-term well-being,” said Barry Downer, deputy director/COO, Oklahoma City Zoo “This is an excellent example of how AZA-accredited zoos collaborate to provide exceptional care and long-term welfare to critically endangered animals. We continue to be cautiously optimistic that Zoya will continue to be integrated into our litter of Sumatran cubs and continue nursing with Lola,” says Downer.


Members from both Philadelphia Zoo and Oklahoma City Zoo will continue to monitor progress of the cubs and share updates as they are available.  The cubs will continue to bond and nurse with Lola in her habitat off public view.  In six to eight weeks, the cubs will be big enough to begin exploring their outdoor habitat and may step outside for visiting guests to see.



Both Amur tigers and Sumatran tigers are endangered in the wild. Fewer than 500 Sumatran tigers may survive on that Indonesian island. Amur tigers, also called Siberian tigers, are found in far eastern Russia, with a few surviving in northeastern China. Sustained conservation efforts have resulted in recovery from near extinction for the Amur tiger. Fewer than 50 were thought to survive in the 1930’s and 1940’s, but the population has grown to less than 500 today.


Although Amur tigers have increased in the wild, tigers overall continue to be under tremendous threat. There are thought to be fewer than 4000 total tigers surviving across their entire range in southeast Asia, Sumatra, China and Russia. The primary threat to tigers is poaching for their skins, bones and other body parts that are used in traditional Asian medicine.  Habitat loss and depletion of prey species is also a threat in many areas.



In 2016 the Oklahoma City Zoo began a partnership with Rainforest Trust, a conservation organization whose mission is to work with local partners to purchase and protect threatened tropical forests. Using funds donated by guests through the Zoo’s grassroots program, Round Up for Conservation, Rainforest Trust purchased 13,000 acres of rainforest in central Sumatra, an area five times the size of Oklahoma City’s Lake Hefner.  This lowland forest is rich in biodiversity and is now designated as a protected area, safe from conversion to palm oil plantations and logging.  The area is patrolled to prevent illegal activities such as poaching. It is home to some of the Zoo’s most popular and endangered species including Asian elephants, Sumatran orangutans and Sumatran tigers.



Gorillas, tigers, orangutans, and other animals living in tropical forests are losing habitat as plantations for palm oil and pulp and paper expand to meet growing global demand. Palm oil is the world’s most widely produced vegetable oil. It can be found in more than 50% of the foods we eat as well as our soaps, lotions, shampoos, cleaning products, and cosmetics. Plantations for pulp and paper are responsible for roughly 30% of Indonesia’s forest loss while an expansion of industrial logging in the Democratic Republic of the Congo threatens the second largest tropical rainforest in the world.

In 2012, the Zoo launched the UNLESS Project, a positive advocacy campaign focused on protecting and restoring forests for wildlife by increasing the use of “deforestation free” palm oil – or palm oil grown without destroying forests. Through the UNLESS Project, Philadelphia  Zoo is mobilizing on-site and online audiences to build a community of well-informed advocates for wildlife and inspiring them to action that will raise awareness of the connection between palm oil and orangutans and tigers.


By driving demand for palm oil that’s “deforestation-free,” reducing waste, and reusing and recycling paper products, UNLESS Project advocates can help protect the forests where tigers and other wildlife live. Philadelphia Zoo encourages visitors onsite and online to send a message from the UNLESS Project thanking and supporting companies who are moving toward sustainably-sourced palm oil, sign up to stop receiving junk mail, to use less paper, save energy, and help reduce the impact of climate change.



Celebrating its 115th year of encouraging guests to conserve wildlife and wild places, the Oklahoma City Zoo and Botanical Garden is the state’s oldest and largest cultural attraction with more than 1,080,000 visitors a year.  The 120 acre park includes more than 1,400 animals with dedicated habitats for primates, rhinos, lions, tigers, grizzly and black bears, hippo, giraffe, zebra, red panda and Asian elephants – soon to reside in Sanctuary Asia a new 6.6 acre habitat opening summer 2018. The Zoo holds accreditations from the Association of Zoos and Aquariums, and the American Association of Museums. For more information or to purchase tickets online, visit www.okczoo.org.  Facebook: okczoobg; Instagram: @okczoo;  Twitter:  @okczoo.  For more great stories about the OKC ZOO, visit okczoo.org/blog. 



Animals are on the move like never before at Philadelphia Zoo with Zoo360, a first-in-the-world system of see-through trails passing through treetops, crossing over pathways and connecting habitats, giving animals like amazing big cats, majestic primates and marvelous meerkats the opportunities to travel and explore. Visit our new baby western lowland gorillas, giraffes, hippos, polar bear, white rhino, zebras, red pandas, Amur tigers and more at America’s first Zoo. Explore our 42 acre Victorian garden and enjoy award-winning exhibits like KeyBank Big Cat Falls, PECO Primate Reserve, McNeil Avian Center and KidZooU, a wildlife academy that offers dynamic displays, rare breeds and hands-on experiences.  Philadelphia Zoo is the second highest ticketed attraction in Philadelphia, one of the region's foremost conservation organizations and home to nearly 1,300 animals, many rare and endangered. By connecting people with wildlife, Philadelphia Zoo creates joyful discovery and inspires action for animals and habitats. The Zoo welcomed more than 1.25 million visitors last year. Philadelphia Zoo is accredited by the Association of Zoos and Aquariums. Philadelphia Zoo is a non-smoking facility.  For more information or to purchase and print tickets online, visit us at www.PhiladelphiaZoo.org. Facebook: PhiladelphiaZoo; Instagram: @philadelphiazoo; Twitter: @phillyzoo.