It's a story that sounds like something out of a feel-good Hollywood pet movie: A 4-year-old indoor house cat named Holly, lost during a family vacation 200 miles from her home, makes a harrowing two-month journey to find her way back. The story even has a tear-jerker ending: The day Holly made it back home was on New Year's Eve, according to the Denver Post.

Holly's trek is an inspiring tale of a cat's resilience and desire to reunite with its family despite the narrow odds and harrowing ordeals she likely encountered along the way. For scientists, though, the saga is as baffling as it is awesome. Unlike some animals, like migratory birds or sea turtles, cats do not have any known homing instinct or internal compass. There isn't even any evidence that they have the kind of long-distance territorial awareness that scientists expect can occasionally lead dogs back home after becoming lost. So how did Holly find her way home?

Though the exact details of Holly's journey remain a mystery, it's unlikely that she was picked up by a good Samaritan and driven home. When she arrived back to her hometown in West Palm Beach, Fla., she was staggering, weak and emaciated. The condition of her feet also gave clues about her ordeal.

"Her pads on her feet were bleeding," explained Bonnie Richter, Holly's owner. "Her claws are worn weird. The front ones are really sharp, the back ones worn down to nothing."

Clearly, Holly was determined to make it home. The fact that she would have had to average more than three miles a day over the course of her journey also tells of just how efficient a traveler she had to be.

"I really believe these stories, but they're just hard to explain," said Marc Bekoff, a behavioral ecologist at the University of Colorado. "Maybe being street-smart, maybe reading animal cues, maybe being able to read cars, maybe being a good hunter. I have no data for this."

Holly's trek especially defies the odds, since she was an indoor house cat. One theory, posited by New York-based animal behaviorist Peter Borchelt, is that Holly might have followed the Florida coast by sight or sound, tracking Interstate 95 and deciding to "keep that to the right and keep the ocean to the left." Nobody but Holly really knows for sure, though, and it wouldn't be prudent to put poor Holly up to the test again.

In fact, little research is available on how cats navigate. One 1954 study, which observed how cats placed in a maze were able to locate exits in the direction of their homes, offers some hints. But the exact mechanism behind the cats' sense of direction is still a mystery.

It's also possible that Holly represents an exception rather than a rule. For instance, cats are not often quite so loyal as some other pets, such as dogs. It's possible that tales of long-distance cat journeys are rare because many cats simply lack the motivation to return home. Perhaps the fact that Holly was kept as an indoor house cat worked in her favor; she didn't know anything else, and felt vulnerable without the familiarity of her home.

Whatever the explanation, it's clear that there's still a lot we don't know about our feline companions. For Holly, though, at least we know she has a happy home, and owners who are thrilled to have her back.

Related post on MNN: Golden retriever leads owner to missing sibling

Bryan Nelson ( @@brynelson ) writes about everything from environmental problems here on Earth to big questions in space.

Cat makes harrowing 200-mile trek to find its way home
Scientists, baffled by the Florida cat's incredible navigational skills, search for answers.