In the June 21 podcast of DJ Dan, Dan speculates that Alvar was transformed into Joop because of Life Extension tests.
Joop was "harvested" in the early 1900s, and that's when they start counting his birthdays, thinking he was no more than a year old when captured and domesticated. However, Joop was actually THREE years old when he was captured, and therefore his last birthday wasn't his 105th, but his 108th.
Joop is actually the body within which Alvar Hanso's brain has been trapped.
Joop isn't really 105. It's an elaborate hoax. Over the years the pictures taken of Joop show his appearance has subtly changed. This is because every couple decades when a previous Joop shows signs of aging, he's replaced by another younger orangutan.
Joop is actually a female orangutan.
Joop is short for Jupiter.
Joop is not actually the Orangutan. On the SaveJoop.com Fansite, someone claiming to be Persephone said (in binary language) "Again, Joop is NOT the ORANGUTAN!" (again, this is not an official site).
Joop died before 1966 and was brought back to life later by the Hanso Foundation.
Joop is a product of parthenogenesis, a form of cloning connected to the IGA.
Joop lives somewhere on the island.
Joop will be freed now that Alvar Hanso is free.
The Life Extension Project has something to do with Richard Alpert's apparent longevity.