Elephants naturally avoid cancer after 55 million years of evolution. Scientists are studying if they can extract lessons that could help people.
Foot problems are more rife in elephants living in captivity. The hard ground they walk on often gives them foot trouble. Generally, by the time the problem is picked up, it's too late.
Keeping such large, intelligent and endangered animals in captivity poses a number of ethical and practical challenges.
The Leuser ecosystem in northern Sumatra is home to some of the world's rarest and best-loved animals. Thanks to a new government moratorium on land clearing, conservationists have enjoyed a big win.