In a recent episode of QI, the television programme chaired by Stephen Fry, it was suggested that Giant Tortoises were not given a scientific name until 300 years after their discovery, in part due to the fact that they were incredibly tasty. This led to speculation by team members that British sailors would arrive back at the docks with guilty expressions and a lot of empty shells…
Darwin’s diary entries from the Beagle voyage note from his time on the Galapagos Islands that tortoise did indeed feature heavily in the diet of the ship’s crew: ‘such numbers yet remain that it is calculated two days hunting will find food for the other five in the week’ However even in Darwin’s time the supply was becoming limited and was reckoned to last approximately 20 years.
Tortoises were fascinating food-stuffs for Darwin: ‘The average size of the full-grown ones is nearly a yard long in its back shell: they are so strong as easily to carry me, and too heavy to lift from the ground’ Despite this fascination, he only fully understood the significance of the existence of different tortoise species on neighbouring islands some time after he returned to England. In a letter to his former botany professor John Stevens Henslow in 1838, Darwin comments that he has gained ‘some curious facts… regarding the lizards and tortoises of those same islands’. With support and wider evidence, his curious facts about the islands lay the groundwork for understanding adaptive radiation.
In 1839, in the Addenda to his Journal of Researches, Darwin regrets ‘not having procured a perfect series in every order of nature from the several islands’ as he had not anticipated while on the Beagle `that islands in sight of each other should be characterized by peculiar faunas’. A reminder that we should pay more attention to what we eat.
 Richard Darwin Keynes (ed), Charles Darwin’s Beagle Diary, (Cambridge, 1988), p.356
 ibid, p. 361
 Charles Darwin, Journal of Researches, 1839, p.629