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Zoo mourns sudden passing of gorilla Leo

Posted by: Gigi Allianic

Leo, a 40-year-old male gorilla, passed away suddenly on March 29, 2018 after a brief illness. Photo by Dennis Dow/Woodland Park Zoo.

Leonel, a male gorilla fondly called Leo, passed away last night at age 40 after a brief illness. The upper middle-age gorilla had been under a 24-hour care this week. He died in his off-view sleeping den.

On Monday, the 360-pound gorilla had no interest in food or drink, and did not want to leave his den to go outdoors. The zoo’s animal health team did a visual assessment and a 24-hour treatment plan that included medications, hydration, hand feeding and observation. Plans to anesthetize him yesterday for a diagnostic exam were canceled because Leo had shown significant signs of improvement. “Leo drank and ate a lot and urinated, a positive sign of hydration. Also, his activity levels increased and we even observed play behavior, so we believed he was on the mend,” said Nancy Hawkes, PhD, Woodland Park Zoo’s director of animal care. “We continued monitoring him overnight. Unfortunately, he died suddenly in the presence of one of his gorilla keepers and close proximity to his family without any warning.”

Leo was the silverback (adult male leader) of his group: 22-year-old female Nadiri; 2-year-old female Yola, daughter of Nadiri; and 16-year-old female Akenji. Leo’s body was kept overnight at the gorilla building so his family and animal keepers could be with him. Gorillas are social animals, explained Hawkes. “This is a devastating loss for Leo’s family, our gorilla keepers and our zoo family. We’re shocked by his sudden death and will provide extra support and TLC for his family group. This is a very difficult time for our staff and volunteers.”

For the immediate future, Nadiri, Yola and Akenji will continue to be in the outdoor exhibit during zoo hours.

Leo, on the far right, with members of his family, young Yola and her mother, Nadiri. Photo: Jeremy Dwyer-Lindgren/Woodland Park Zoo.

The median life expectancy for male western lowland gorillas is 32 years old, although gorillas in zoos can live in to their 40s and 50s because of the evolving field of zoo medicine including improved husbandry and management techniques, excellent animal care, better nutrition, increased medical knowledge, and diagnostic and therapeutic techniques.

As a standard procedure, the zoo’s animal health team will perform a necropsy (an animal autopsy) to determine the cause of death and to share the results nationally among scientific colleagues to help advance the understanding of medical issues in gorillas, explained Dr. Darin Collins, Woodland Park Zoo’s director of animal health. The cause of death is pending final pathology tests in several weeks.

Leo’s rise to becoming a leader in a cohesive group and a surrogate father to Yola is an incredible story. Leo moved to Woodland Park Zoo in 2008 and, because of the incredibly dedicated team of compassionate and determined gorilla keepers, he was successfully socialized into his existing family, and respected and loved. Read Leo’s extraordinary story here.

In remembrance of Leo, please consider these actions:

All gorillas are threatened by habitat loss, wildlife trade, hunting, disease and human conflict. Critically endangered and losing ground every day in the wild, gorillas need our help.

Recycle cell phones for gorillas
Come recycle your handheld electronics with us through ECO-CELL to preserve gorilla habitat. By reclaiming the minerals in your electronics and diverting them from landfills, we can reduce demand for mining in gorilla habitat. 

How: Bring any old cellphones, MP3 players, or tablets hanging around your house to the zoo and drop them off at our ECO-CELL stations.

Funds generated from recycled electronics will go toward our Mbeli Bai Gorilla Project that works to protect gorilla families like Yola’s in the Republic of Congo. 

Adopt a ZooParent gorilla
ZooParent adoptions are the perfect gift for budding conservationists. Your ZooParent adoption helps us provide exceptional care for all of Woodland Park Zoo's amazing animals. Plus, your support contributes to our conservation efforts at the zoo and around the world.

Visit the zoo
Every visit to Woodland Park Zoo helps support conservation efforts like our Wildlife Survival Fund project, the Mbeli Bai Study. The study researches the social organization and behaviors of more than 450 lowland gorillas living in the Republic of Congo, providing the scientific basis for conservation strategies.


Tura said…
This is heartbreaking news. I always loved watching him interact with the younger gorillas he so sweet and gentle with them. I'm sure his entire zoo family (human and animal) are mourning him. Rest in Peace, Leo.

Unknown said…
This is a devastating loss. What’s going to happen to his family. Perhaps they can be intergrated into Vip’s group