Jonathan the tortoise is 194 — and a new study says he's aging more slowly than expected

Jonathan, a giant tortoise on St Helena — about 4 feet high and 5 to 6 feet long — is 194 years old, the oldest known living land animal. A study published this week in Science Advances found his gene regulation resembles that of a very young animal: he is 'genuinely aging more slowly than we would expect,' researcher Justin Gerlach of Peterhouse, Cambridge told NPR's Mary Louise Kelly. He arrived on St Helena 144 years ago, a gift to the island's governor, and spends his days grazing in a pasture.