On 5 Feb 2018, Souther White Rhino Chuck was euthanized in San Diego Zoo Safari Park (USA) at the age of ~50 years old. In the recent years he endured a significant decline in health, and the initial finding of the necropsy are that Chuck had various age-associated ailments, especially arthritis, which made walking painful.

He was a very smart rhino: hea learned how to open gates, so the zoo keepers had to create some special ones just for him, the so called Chuck-proof gates.
He was the longtime companion of Nola, one of the 4 last Nothern White Rhino, who passed away in 2015.

He also sired 14 offspring. Some remain at the zoo, but most have been sent to other zoos and conservation parks.

For the original article -> http://www.sandiegouniontribune.com/news/zoo/sd-me-chuck-rhino-20180205-story.html