According to a related article: https://www.discovermagazine.com/why-its-nearly-impossible-to-castrate-a-hippo-4775 https://www.discovermagazine.com/why-its-nea

According to a related article: https://www.discovermagazine.com/why-its-nearly-impossible-to-castrate-a-hippo-4775 https://www.discovermagazine.com/why-its-nearly-impossible-t... The death was caused by an "unknown pre-existing condition" but doesn't elaborate further.