Once a species is considered extinct, it usually stays that way. But not so for an Australian stick insect that had been considered extinct since the early 1920s, and officially extinct by 1986. Alas, they have come back from the dead.
The "tree lobster," or "land lobster," or Dryococelus australis, was a native to Australia's Lord Howe Island, but was wiped out after a 1918 shipwreck unleashed black rats, which decimated not only the D. australis species on the island but other species as well, including "five birds, two plants and 13 invertebrates (including D. australis) – not found anywhere else in the world," according to Science Alert.
Then in 2001, the insect was discovered alive on nearby sea volcano, Ball's Pyramid, yet it wasn't official that these creatures were indeed the tree lobster – they didn't look quite the same as their Lord Howe Island ancestors. But "DNA testing has confirmed that the insects are, indeed, D. australis – an extremely rare success story."
According to Science Alert:
Although the Ball's Pyramid insects didn't look like the Lord Howe Island specimens, comparison between the genomes of the two found less than 1 percent difference – a small enough difference that they can officially be declared the same species.
This means that eventually, they may be reintroduced to Lord Howe Island, pending the completion of a rat eradication program that is due to commence in 2018.