When the giant Galapagos tortoise faced extinction, Diego answered the call

The Wikipedia article on Diego mentions that there was actually another tortoise in the same breeding programme that fathered even more offspring. The paragraph on the breeding programme made me laugh:

The three male tortoises were placed into breeding pens with different females and the offspring released onto Española as juveniles, once or twice a year. The survival rate of the offspring on the island was around 50%. During this time Diego fathered around 900 offspring, some 40% of the programme's output.[1] A second tortoise, known as E5, fathered most of the remaining 60%, with the third male, E3, producing very few offspring.[5]

Despite E5's being more successful at reproducing, Diego has received the majority of media attention and has been said to have "had so much sex he saved his species".[5] This is believed to be because E5 had a more reserved character, a less interesting name, and was seldom witnessed in the act of mating.[5][6] Diego, by comparison, has been described as aggressive, active and vocal in the act of mating, which in turn made him popular with the female tortoises.[1]

From https://en.wikipedia.org/wiki/Diego_(tortoise)