House Cat-Odyssey Highlights The Mysteries Of Animal Migration
Early in November, a tortoiseshell cat named Holly jumped out of her human family's RV in Daytona Beach, Florida, and ran off. After a fruitless search, the husband and wife returned home to West Palm Beach without their cat.
Holly showed up back in West Palm Beach, only a mile from her house, on New Year's Eve. Because she had been micro-chipped, the family, two surprised and grateful humans and one bedraggled cat, were readily reunited.
But how did Holly find her way home across those 200 miles? As The New York Times reported on Sunday, the worn condition of Holly's feet and claws show that she walked a considerable distance. This fact, together with Holly's having lost nearly half her body weight, rules out the idea that she'd been a passenger in someone's car. With startling accuracy, Holly covered at least most of the mileage by padding along day-after-day through habitat wholly unknown to her. As the Times article makes clear, experienced animal-behavior scientists like John Bradshaw and Marc Bekoff have no explanation for how she did it.
Holly's story caught my eye not only because I'm cat-besotted (and a homeless-cat rescuer), but also because animal navigation is a thriving area of scientific research. Animals — from birds to whales — cross impressive distances during seasonal migrations. Curlews, for instance, fly 6,000 miles non-stop en route from the South Pacific to Alaska.
Just three days ago, I observed wild humpback whales off Virginia Beach as they migrated from the far north (possibly Greenland) to the Caribbean. Mark Jennings from the Virginia Aquarium and Marine Science Center explained to me that those of us on the tour boat were watching juvenile and young adults who were "slow migrators," whales following at a somewhat leisurely pace behind the pregnant females and fully adult breeders who had already gone south at speed. The boat captain was respectful in not getting too close to the whales. Even so, at one point I could hear as well as see two of them, side by side, as they spouted. It was a joyous feeling to share that one fleeting moment with them, during their journey.
Ecologist James L. Gould and science writer Carol Grant Gould write that, in navigating like this, many animals "are performing feats far beyond anything humans can manage without specialized instruments, equipment, and training." In their book published last year, Nature's Compass: The Mystery of Animal Navigation, Gould and Gould show that the best data on animal, including insect and bird, navigation come from experimentation rather than observation alone.
In my review of the book for the TLS, I noted some of my favorite experiments described by the Goulds:
A hive of bees trained to feed at a certain hour is transported from Paris to New York; the bees fly to feed at five hours earlier than local time, but recover from this jet lag within a week by shifting to true solar time day by day. Block ants' view of the sun and offer them a mirror-image reflection from a different direction, and they turn around in their tracks. Require pigeons to carry magnets on their backs on cloudy days, and they get lost. Intercept birds in the process of migrating, and you find that the juvenile and adult coping strategies are different, which plays into an experience-dependent notion of bird navigation.
As that last sentence hints, Gould and Gould in their review find that some animals navigate via instinct, and others through accumulated experience and learning. Humpback whales are good candidates for some learning in their migratory behaviors (see Table 3, page 13 here), which some recent research also suggests may involve making use of star maps as well as the sun's position and Earth's magnetism.
Where does Holly the housecat fit into this picture? She's not saying, and no scientist plans to release cats 200 miles from home under different experimental conditions in order to assess how they navigate.
For now, this feline leaves us with unanswered questions.
You can keep up with more of what Barbara is thinking on Twitter: @bjkingape