"His age is estimated because he was "fully mature" when brought to Saint Helena in 1882. "Fully mature" means at least 50 years old, giving him a hatching date no later than 1832.[8] A photograph featuring Jonathan originally thought to date from 1902 actually dates from 1886,[2] showing Jonathan four years after his arrival on Saint Helena. Measurements taken from the photograph show that he was fully mature in 1886.[citation needed]"
In December 2015, the St Helena vet Joe Hollins said that Jonathan was "alive and well [...] He's blind from cataracts, has lost his sense of smell, and so cannot detect food (his fellow giants mug him and can detect the tiniest morsel dropped on the ground), but he has retained excellent hearing."[1]