Narwhal the Rescue Puppy Adoption Applications Halted Amid Shelter Concerns

The rescue puppy with the tail growing out of his head will have to wait to find a forever home, because the shelter's worried some folks applying to adopt him might have the wrong motives.

As we reported ... the undeniably cute little dog named Narwhal is "a perfectly healthy puppy, with an extra tail on his face" who was rescued by Mac's Mission Animal Rescue in Jackson, Missouri. Naturally, he's gone viral due to his unique condition.

The shelter has received hundreds of adoption applications for Narwhal, but its founder, Rochelle Steffen, tells TMZ ... she's pumping the brakes for now. She says on Wednesday alone they got more than 100 applications, which is highly unusual because they are normally lucky to get one for a "special dog."

She tells us the shelter is nervous people may be wanting to adopt Narwhal for the wrong reasons -- for instance, fame and notoriety -- and not for love of a family pet. As a result, Rochelle says they're halting the application process for at least 2 months.

Rochelle says they've never had a dog like Narwhal, so they want to keep him and let him get bigger while they monitor the tail and make sure there are no negative health effects. If all's well in 2 months, they will put him back up for adoption, but she says they'll likely add a few questions to narrow down prospective candidates.

Rochelle adds, Narwhal's been checked by a vet and she's been told there is no reason to remove the tail -- it doesn't wag and has no bone structure -- so it would be a cosmetic surgery.