Difficulty: Summiteer (Level 3)
The oldest-known land animal in the world is an Aldabra giant tortoise named Jonathan. He is believed to be 194 years old.
Scientists think that his amazing long life might be because of a mix of special genes and his ability to keep important systems in his cells working as they do in younger animals.
Members of this species are known to live more than 100 years, but Jonathan has far exceeded that. Scientists have studied Jonathan to explore the secrets of the animal’s longevity.
The researchers identified 287 genes with variants unique to Jonathan, including some linked to tumour suppression and DNA repair. The tortoise also carries extra copies of a gene that encodes a protein that hunts down ageing and cancerous cells.
