Shapeshifting, as this site defines it, is the act of changing some or all of your physical form into that of another creature. While spiritual and mental forms of shapeshifting are valid, this site focuses primarily on the physical - shifts that have physical effects on a person or their world.
The Western shifter community is composed of many different shifter breeds and beliefs, and in some ways has not diverged far from its roots.
Thousands of years ago, humans who could change their form weren't unheard of. Not just in a metaphorical sense, but often in a spiritual and even physical way. Through magical, spiritual, or scientific means these individuals would change into other animals or beings, and roam the world in these new bodies.
Some took on canine, ursine, or feline forms, but just as many took on reptilian, avian, or cervine forms, among others. They would be called werebeasts, monsters, shapeshifters, and more, and as the human race clashed and collaborated with them, stories, myths and legends would be written about these shapeshifters.
But surely those were just legends, right? Werewolves and shapeshifters are just fictional, and nobody claims to be one in the present day, right?
No, these were not just myths.
People and groups claiming to be real shapeshifters or to possess the ability to shift have continued to exist all over the world, forming their own communities and cultivating supernatural beliefs.