I'm curious: is therianthropy, or feeling like otherkin, pretty much a life-long undeniable thing or is it more like, for lack of a better word, a hobby?
The way people describe therianthropy or otherkinness, it seems to be in terms like the second category above, but does that seem to be the case in practice? Do people feel as if they're a wolf pretty much from cradle to grave, or do they look back at age 50 and wonder: why did I ever think that when I was 20?
I think that for most therians, it is more something you are, not anything you can do one day and decide to stop doing another day. So, more like being left-handed or shy or gay than being a dancer or gamer, in that sense. At least for me, I really feel I am a wolf somehow, and even if I can imagine that perhaps I one day would find out that my behaviours match some other animal (coyote, dog...) better, I don't think I will ever feel completely human. But my feelings about this matter fluctuate. Some months I will feel unusually human and normal, when I was younger I thought that perhaps that whole wolf-thing was a phase and it passed. Then it comes back, and at it's strongest I am unhappy with being human and start to research the possibility of fur and tail implants...
While there have been people first stating they are therian or otherkin and later leaving the community, many of them have had pretty good reasons for thinking they were therian. They might have been very bonded with a pet, or the animalistic spirituality was better described as totemism, etc. There are also many who still consider themselves being therian or otherkin, but have tired of the community and therefore leave.
But I do know of middle-aged therians, some of which have been involved in the community for a long time. There will also always be people who identify as animals, but haven't heard of the therian community, perhaps because they think they are insane, alone and that there is no point in trying to look for others like them. For example, my boyfriend "is" a cheetah, but he didn't know of the community until he met me and still isn't interested in joining. He is happy with just being able to purr or chirp when he is with me, he has no interest in discussing this with strangers.
There's also some confused teenagers coming to the communities, thinking it is something similar to role play... You can recognise them by their over-the-top usernames ("ShadowIceWolf", "Claw of the night") and their questions about how to physically transform... They leave when they found out we aren't cool werewolves and tigermen fighting vampires under the full moon. In the therian community, we jokingly call them fluffies or "tr00 weres", the otherkin community has "elven princess syndrome", where a person claims to have been an important creature in a past life (often royalty) and demand special privileges and extra-ordinary respect. "Elven princesses" are scorned as rude or just role playing.