While we think we've solved the mystery of how Willow, the Colorado cat who went missing five years ago only to surface in New York this week, traveled to the Big Apple, there are still many questions. Like how could Willow's microchip, with information about her Colorado home, not be detected? Well, there are some theories.

Our tipster mentioned that after a New Yorker found Willow while skiing in Colorado, he brought her to a local vet to get her cleared to fly back to NYC and "none of her history came up." We spoke to Dr. Peter Soboroff of New York Cat Hospital, who mentioned that different pet microchip manufacturers use different frequencies, and only in the past few years have there been universal scanners that can scan for all chips. Therefore, it's not entirely out of the question that Willow was brought into a vet and scanned with a scanner set for frequency different than her chip—resulting in a blank for information. (You don't need to re-microchip your pets if you got them microchipped a while back—most vets and shelters have universal scanners now.) Another possibility is that the vet didn't even have a scanner.

Further, Dr. Soboroff also believes that most vets would scan for a microchip if the cat was presented as a stray found on the street, but if a new client brought in a cat and claimed it was his/her own, a vet might not necessarily think to scan it.

At any rate people, MICROCHIP YOUR CATS AND DOGS. You may think, "Oh, I live in the city, my cat won't get loose," but you never know—kitty could run out while you're taking him/her to the vet, or kitty could run out when a cat sitter opens the door—or a Hurricane could even blow through town! And Willow, who will be reunited with her family next week, will always hold New York in a special place in her heart. She wrote on Facebook, "Dear New York, New York: I love you. I plan on being a New Yorker forever even when I live in Boulder. If a bear or mountain lion messes with me I can say 'You got nothing, I am a New Yorker.' (I am pretty sure my humans are not going to let me out of the house but if a bear or lion comes in the house, It's on like Donkey Kong.)"