Denver Zoo Map
July 23, 2013


Zoo Lion Pride Also Faces Critical Age-Related Health Issues

Denver Zoo is deeply saddened to announce the death of Natal, a female South African lion that would have been 16 next month. Natal was suffering from cancer and having lost her quality of life, zoo veterinarians humanely euthanized her the evening of July 22. 

Natal arrived in Denver with the opening of Predator Ridge in the spring of 2004. Natal was best known as the nurturing surrogate mother of an orphaned lion cub, Asali. Asali, born in 2005, was not cared for by her birth mother but got a second chance when Natal took her under her care and raised the cub as her own. Natal then gave birth to a female lion cub, named Kazi on October 25, 2006. 

"We'll miss her. Losing her so close to Rian the lion has been very hard for all of our staff," says Predator Ridge Curator Hollie Colahan. "Our three remaining elderly lions are all similar in age and facing associated health issues. Our keepers love these animals and it's just a difficult reality to face."

Biopsies conducted last week showed Natal had a tumor in her breast and cancer throughout her body. The tumor, a common one found in older female cats, was large and had invaded the lymphatic ducts around the mammary gland. Test results also showed cancer in the spleen. Without hope for recovery, zoo staff opted to keep Natal as comfortable as possible and monitor her quality of life. When Natal became extremely lethargic and stopped eating, staff made the difficult decision to euthanize her.

"This type of cancer is very aggressive and is not responsive to most treatments. Unfortunately, there was no course of treatment that could make her better. As she continued to decline, the humane decision was to euthanize her," says Staff Veterinarian Betsy Stringer. 

The median life span of lions in zoos is 16.8 years, while lions in the wild live about 15 years. Denver Zoo lost 15-year-old lion, Rian on June 19. Rian was being treated for cancer and although showed initial improvement from chemotherapy, he took a turn for the worse and was humanely euthanized. In February, the zoo also lost a 15-year-old lion named Tawny who was found to have cancerous cysts preventing the proper digestion of food. Currently staff is monitoring the quality of life of 15-year-old Krueger, a male lion that has been diagnosed with cancer and keeping a close eye on Baby, a 15-year-old female that has been showing signs of inappetence.

"The lions that we have lost have all developed different types of illnesses that only have one thing in common – you see them with elderly animals at the end of their lifespan. Unfortunately, these lions that we have loved watching flourish in our Predator Ridge exhibit since 2004 are at the end of their life span. This is the hardest part of working at the zoo – knowing you'll eventually have to say goodbye," says Dr. Stringer.

"When we brought in two prides of lions to Predator Ridge, our staff knew it would be difficult to have six lions that were all the same age when they reached the end of their life span. I'm proud of the team at Predator Ridge and our veterinary team for the outstanding care they provided to our elderly lions that have passed away and for the care they continue to provide to the remaining lions in this area," says Denver Zoo Executive Vice President/COO Kyle Burks. 

Denver Zoo is also home to 15-year-old male Rajah, Rian's brother, and the zoo's two young lions, one year-old female Sabi and a new one-year-old male named Sango. Sango is currently in quarantine after arriving from Ellen Trout Zoo and is expected to begin enjoying his outside yard next week. 

In addition to providing the best in care for the lions that live here, Denver Zoo is committed to lion conservation around the world. Predator Ridge Curator Hollie Colahan will travel to Botswana this week for a field conservation project aimed at reducing the conflict lions face with ranchers losing their cattle as prey. The unique project will attempt to taint the wild lions' pallets to the taste of cattle through a harmless taste aversion substance placed on beef. 

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