They have developed a sane, but unusual obsession with furry/anthropomorphic characters! (animals with human characteristics)
Most furries have developed their problem from a very young age, showing how vulnerable our children are to the mischievous Mickey Mouse!
Anthropophormic characters are EVERYWHERE!
Video games, children books, cartoons, movies, name it! They have begun their invasion and they aren't planning to stop now!
They think of humans as just another animal!
God has put us humans on Earth to rule over the other species, not to be their equal!
They have fursonas
They took the "which animal are you?" quizzes way too far; adopting the personality of an animal!
They raise funds to find home to homeless pets!
Instead of letting vetenarians kill off pets with no owner to retrieve them, they defy nature trying to "help" those animals by finding them new homes! They certainly weren't abandoned by their original owners for no reason in the first place!
Some of them wear fursuits!
They dress up in a mascot-like costume, and will try to fool you by being nice and huggy to everyone, but don't be fooled! Once they hug you, you might become one of them!
Note: Pepper spray tends to be useless against fursuits, but they'll stop hugging every non-furry afterward.
They Role Play as animals/fursonas...
Beware when they want to be petted or anything that may seem affectionate. They might be growing attached to you, so you should break bonds immediately before it's too late! It's just another way for them to try to convert you to their cause.
They are sneaky
The person you suspect the least may be a furry. They are in higher proportions from psychology and medical fields. Suspect anyone who seems unusually helpful and who likes animals!
They don't reveal their faces... those that will stop to nothing to show their furriness to the world may wear suits... But really, there must be something wrong about them for them to hide!
They are obviously confused with their sexuality
Some of them even think they are part animal or should've been born as an animal, yet zoophilia is uncommon among furries. Heck, there doesn't seem to be much sexual aspect in the fandom for the majority of furries. Sex is what brought them here and it's their reason to be; they defy nature! They aren't honest with themselves in one way or another. You can't trust these people!