Some animals don’t age.

Their cells age at a negligible rate and theoretically these animals would live forever or a really really long time if they didn’t get eaten or a disease. They can still die, of course, but even if they are many years old, their cells look about the same as those of a young animal. One example is the immortal jellyfish which can cycle perpetually between its “child” and “adult” forms. The FoxO gene is responsible for this perpetual youth (hey why doesn’t someone make an anti-aging cream out of that). American lobsters never stop growing as adults and even adults can regenerate a lost limb. Their chromosomes have tips that protect their DNA. The mollusk ocean quahog has been found to be up to 507 years old. They have cell membranes that resist cell damage to keep their cells looking young.