Big Tim, a beloved elephant who was one of Africa's last giant "tuskers", has died, the Kenya Wildlife Service (KWS) said on Wednesday.

"The celebrated elephant died early Tuesday morning aged 50," KWS said in a statement.

A survivor of poachers, Big Tim was found dead of natural causes in Amboseli National Park at the foot of the snowcapped peak of Kilimanjaro, the Amboseli Trust for Elephants said.

He was "a benevolent, slow-moving preserver of the peace at Amboseli," KWS said. "He was well known and loved throughout Kenya."

An elephant is technically a "tusker" when its ivory tusks are so long that they scrape the ground. Usually, only old bull elephants grow their tusks long enough to reach this acclaimed status.

But conservationists estimate only a few dozen such animals with tusks that size are now left on the continent.

This because poachers target the animals with the biggest ivory, and elephants with the heaviest tusks are most at risk.

With the big tuskers killed first, that reduces the gene pool; as a result most elephants in Africa today have smaller tusks than they did a century ago, scientists say.

Tim was named by researchers who called each elephant in the family herd they were monitoring by the same letter to help identify them; Tim was a member of the 'T' herd.

The giant pachyderm once roamed outside the national parks into farming lands and had survived poachers and angry farmers. Vets once treated him for a spear that had gone through his ear and snapped off into his shoulder.