There really is no established Therian symbol. However, there is a symbol that is generally accepted as the Therian symbol.
"The Therian Symbol was created by members on The Werelist a while ago. The intent was to make a universal therian symbol for the entire community. Most of them adapted the basic design (a Greek theta symbol interwoven with a delta) into a unique charm with personal significance to them. Those therians began calling the symbol by a specific name, which seems to fit its Greek origins- therios." - Therian Wiki and also,
"The Theta Delta is believed to have origionated from an early incarnation of The Werelist, where it was decided on in a forum topic that revolved around the creation of such a symbol. The Theta Delta was created, Theta, being a T, used to represent the word "Therian" and Delta for a change, as in a shift."-Therian Wiki
Some Therians prefer to use their own symbol and others prefer no symbol at all. All in all it's your choice to pick a symbol that defines Therianthropy to you.
Otherkin: An umbrella term for those who believe they are non-human on a spiritual, neurological or psychological level. This includes therianthropes, plantkin, mythkin, draconics, fictionkin and otherwise.
Animal Hearted/Other Hearted: Someone who identifies with (not as) an animal or creature. This can be an obsession, connection or strong fascination with an animal or creature. As with kintype and theriotype, one would say "kith". "I am ___kith", the underscores being replaced with what one identifies strongly with.
Phytanthrope/Plantkin: A person who believes that they are a plant or multiple plants on a spiritual, neurological or psychological level. This includes any plant life.
Mythkin: Those who believe they are a creature from mythology on a spiritual, neurological or psychological level.
Fictionkin: Someone who identifies as a fictional species, one not yet aged enough in modern culture to be considered mythology or folklore on a spiritual, neurological or psychological level.
Draconity: Someone who identifies as a dragon.
Copinglink: (Formerly called Copingkin); People who use a non-human identity as a way to cope with a mental illness or disorder. These individuals are not otherkin or therians due to the fact that a non-human identity is not something that you can choose to have. The name was changed from copingkin to copinglinkers to denote that they are not associated with the otherkin community.
An umbrella term for people who identify as non human beings and have such experiences and feelings. While Therians include only earthly animals, Otherkin in total can include any creature whatsoever, so while Therian is used to describe earthly animals, Otherkin is used to describe anyone who doesn't fall in that category be it mythical creatures like Gryphons, Dragons, Angels or any other thing like Aliens, entities, energies or something completely different.
Therians are often confused for furries, however there is a huge difference between the two.
It is not too common but some therians join furry communities and get involved with the furry fandom. Therians are not likely to wear costumes but don’t be surprised to find some wearing tails or masks.
At the Therian Guide, we have a lively community on our forums with hundreds of members, loads of new posts daily and usually someone to talk to whenever you show up. However we also have an expectation of privacy. Therianthropy is a very personal thing and we are quite shy. Because of this, we will need you to write something about yourself, before we let you join us.
At the end of the registration process you will be asked to make an introduction in the forum, answering a few of our questions (see stickied post). We may ask you additional questions before your application is processed, please check back and answer them on the forums.
We are open minded and welcome everyone, but please understand these few basic requirements.