Turtles Never Die Of Old Age

From "The Gullibility Test" at themuseumofhoaxes.com:

CLAIM: Turtles never die of old age.

ANSWER: TRUE. Turtles exhibit what is known as 'negligible senescence.' In other words, unlike humans, they do not continue to age once their bodies reach maturity. In theory, they might be able to live forever, though in practice this would never happen. Injury, predation, or disease eventually kill them. But turtles have been known to live beyond 150 years without exhibiting any signs of old age. Fish and amphibians also share this enviable characteristic.

That seems kind of impossible to me, but I'll take their word for it.