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Summary of Description:
Luke, a 17-year-old African lion at the Smithsonian’s National Zoo and Conservation Biology Institute, was humanely euthanized on October 19 due to a reduced quality of life caused by liver cysts and spinal issues. Luke arrived at the Zoo in 2006 due to a breeding recommendation from the Association of Zoos and Aquariums’ Species Survival Plan, and he sired 13 surviving cubs. Animal care staff treated Luke for occasional discomfort and lameness in his right forelimb since 2016. Luke’s spinal conditions worsened despite various treatments, and he lost weight and appetite. African lions are considered a vulnerable species, with populations declining by about 30% in the past decade and an estimated 20,000 remaining in the wild.
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Smithsonian’s National Zoo and Conservation Biology Institute sadly announced the death of their African lion, Luke. After experiencing occasional discomfort and lameness in his right forelimb since 2016, Luke was humanely euthanized on October 19. Animal care staff diagnosed him with an intervertebral compressive disc lesion on his spine last year. His condition worsened despite various treatments, including steroid injections, anti-inflammatory medications, and deep-tissue laser therapy.
The veterinary team made the difficult decision to euthanize Luke due to his overall poor quality of life, hoping to gain more insight from the pathology report. The keepers noted that Luke had lost significant weight and appetite. This prompted an exploratory exam that found several cystic masses throughout his liver and moderate-to-severe progression of his spinal condition.
Born in South Africa in 2005, Luke was the most genetically valuable lion in the North American population when he arrived at the Zoo in 2006. The scientists considered his genetic makeup, nutritional and social needs, temperament, and overall health in their breeding recommendation from the Association of Zoos and Aquariums’ Species Survival Plan (SSP). Luke sired 13 surviving cubs from four litters with his mates Naba and Shera. His behavior provided valuable insight into lion breeding and cub rearing behaviors, contributing to scientists’ knowledge about African lion reproductive physiology.
Luke’s death is a great loss to the zoo community, as he played a significant role in adding to visitors’ knowledge and appreciation of African lions. Along with his mates and offspring, his presence helped raise awareness about the vulnerable status of African lions due to hunting, disease, and habitat loss. Luke’s contributions to his species’ survival and his gentle nature as a protective father left a lasting legacy, making him the “king” of the Great Cats exhibit and an educational icon for millions.
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Source Description
Staff at the Smithsonian’s National Zoo and Conservation Biology Institute are mourning the loss of Luke, an African lion who was humanely euthanized on October 19. He was 17 years old. The median life expectancy for African lions in human care is 17 years.
Animal care staff had been treating Luke for occasional discomfort and lameness in his right forelimb since 2016 when keepers observed that Luke was not bearing full weight on his leg and was showing signs of significant pain. Veterinarians anesthetized Luke and examined his leg, shoulder, neck, and spine. A CT scan revealed an intervertebral compressive disc lesion on Luke’s spine. Over the years, the veterinary team administered various treatments for Luke’s spinal disease: steroid injections, anti-inflammatory medications, other oral pain medications, deep-tissue laser therapy, electroacupuncture, and dry-needle acupuncture on the affected areas. However, the staff elected not to perform surgery due to significant complications that could arise related to post-surgical care.
Luke was trained to voluntarily participate in awake health exams, including routine weigh-ins and blood draws. On October 14, keepers noted that Luke had lost 8 kilograms or 17.6 pounds and was experiencing repeated episodes of lack of appetite. An awake blood draw performed that day did not reveal any areas of concern. Early this week, keepers noted that Luke had a decreased appetite and appeared dehydrated; additionally, his hind limbs seemed to have a generalized loss of muscle mass. During an exploratory exam on October 19 to identify the cause of his weight loss and lack of appetite, Zoo veterinarians found several cystic groups throughout his liver. They also found the moderate-to-severe progression of his spinal condition—several of his cervical vertebrae had fused. Given these findings, Luke’s overall long-term quality of life was considered poor, and the animal care team humanely euthanized him. A final pathology report will provide more information in the coming weeks.
Born at a private reserve in South Africa in 2005, Luke arrived at the Zoo in October 2006 following a breeding recommendation from the Association of Zoos and Aquariums’ Species Survival Plan (SSP). The SSP scientists determine which animals to breed by considering their genetic makeup, nutritional and social needs, temperament, and overall health. At that time, Luke was the most genetically valuable lion in the North American population because his genes were not represented in U.S. zoos. Luke sired 13 surviving cubs from four litters with his mates, Naba and Shera. The cubs—born in 2010 and 2014—were transported to North American zoos for breeding and research. Zoo visitors can see Shera and her offspring Amahle, Shaka, and Jumbe on exhibit or the Zoo’s Lion Cam.
“Luke was truly the ‘king’ of the Great Cats exhibit,” said Craig Saffoe, curator of Great Cats, Kids’ Farm, and Andean Bears. “He was gentle with his mates, Naba and Shera, and an extremely patient and protective father to all 13 cubs he sired. Luke has left a lasting legacy, not only in the cubs he contributed to his species’ survival but also in the millions of visitors who gained a deeper knowledge of and appreciation for African lions because of who he was as the patriarch of his pride.”
Observing his behavior gave the Great Cats team valuable insight into lion-breeding and cub-rearing behaviors. His contributions to his species’ survival helped increase scientists’ knowledge about African lion reproductive physiology.
The formation of pride makes lions unique among the great cats, many of which are solitary animals. Hunting, disease, and habitat loss have contributed to a decline in the African lion population, which is considered a vulnerable species by the International Union for Conservation of Nature. During the past decade, lion populations have declined by about 30%. Currently, an estimated 20,000 lions remain in the wild.
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