The Three-Minute Outdoorsman: Wild Science from Magnetic Deer to Mumbling Carp

54. Outfoxed Again!

A N I M A L I N T E L L I G E N C E 209 mic needle with microscopic barbs.” Their prototype behaved the same as barbed porcupine quills, and presumably their keeping the barbs microscopic minimized the pullout force. This is a good example of having to solve competing problems: you want your needle to penetrate more cleanly and with less force but not be as hard to remove as a porcupine quill. Their work could actually lead to inoculations that would be less painful. Many of our most convenient products were inspired from study of evolution’s success stories. For example, study of cockleburs led to the development of Velcro. By studying the results of millennia of natural selection on porcupine quills, these folks learned a lot about what we only knew superficially (if not painfully ). How natural selection has solved the opposing actions of penetration and pullout is fascinating. But rather than acquiring this knowledge for purely academic reasons of limited value to humans, the investigators concluded that “mimicking the porcupine quill should be useful for biomedical applications including local anesthesia, abscess drainage, vascular tunneling, and trocar placement in addition to the development of mechanically interlocking tissue adhesives.” Maybe we should have a little more respect for porcupines after all! 54 outfoxed again foxes use built-in range finders! We tend to view ourselves as the ultimate observers. We can experiment, watch, record, and interpret what animals do in the real world, and we’re pretty sure they don’t have the same capabilities . Our confidence in our abilities was shaken, however, when we figured out that birds see in the ultraviolet spectrum. We now know that wild turkeys, for example, are communicating with t h e t h r e e - m i n u t e o u t d o o r s m a n 210 each other via a channel we don’t subscribe to, via UV-reflecting patches on their feathers. Actually, if you washed your old hunting clothes for years with the wrong detergent, it actually brightened their UV reflectance, making you stand out like a beacon. Oops. Another surprise, albeit fairly old now, was that many animals make use of the earth’s magnetic field. Birds, for example, use the magnetic field as a compass during migration. Cows and deer orient magnetic north when they are not stressed or being chased, and winter beds of deer are also oriented north–south. That means they can sense the earth’s magnetic field and consistently orient north–south. Scientists aren’t sure why they do this, but a possible reason is that when these social animals are dispersed by a predator, they can regroup easier if they all head in the same direction—magnetic north. These results make one wonder if many animals use magnetic directional information in other ways we are unaware of. Hynek Burda and colleagues from the Czech Republic have now reported that the red fox senses and uses the earth’s magnetic field in an unexpected way. I have seen hunting foxes a few times, and they exhibit a behavior called “mousing.” The fox detects a prey species, such as a mouse, approaches, sets itself, and then jumps high in the air and arcs downward on the mouse from above. Before the jump, foxes perk up their ears and tilt their heads back and forth, apparently using their sense of hearing to get an exact fix on the mouse. What’s magnetic about this? You would expect that if you watched one hundred attacks, they would be spread out over 360 degrees with the direction depending on circumstances like wind, vegetation, where the fox was when it detected a mouse, and so on. However, researchers had noticed before that fox attacks were not directionally random . That’s suspicious. So the Czech scientists had twenty-three wildlife observers record fox attacks and the direction they oriented when they executed an attack. The observers kept track of A N I M A L I N T E L L I G E N C E 211 whether the jumps were in low or high grass and whether they were successful. In low cover there was no deviation from random. However, 75 percent of all successful attacks in high cover were centered about 20 degrees clockwise of magnetic north. That’s clearly not random...