Lonesome George, the last of it's kind, may also be infertile. At the ripe age of 90 and just hitting his sexual prime, the hits just keep on a coming for this poor fellow.
1- encouraged to mate with 2 male tortoises. HEY!!! We didn't know those two were male mkay?
2- placed with two female tortoises (we hope) but shows no interest.
3- 6 months of failed genital manipulation by female staff member to produce semen sample for artificial insemination. Six MONTHS of trying before the grant money ran out. That's right. She got grant money to jack off the world's rarest tortoise for 180 days.
4- He finally manages to fertilize some eggs when horror of horrors, 80% have failed to quicken. Being the only known survivor of a species of tortoise and the world's rarest animal, the other 20% of his fertilized eggs are being kept in an incubator painted with religious figures.
Yeah, THAT should improve their odds of survival.