|
09/01/2014
Animals Getting Smarter
CHAPTER 48 Clever Creatures
These days one often sees or hears media reports about wildlife in our towns and cities. Bears and coyotes abound here in New Jersey and the metropolitan New York area. About a month ago, I was eating breakfast and noticed a young deer in our backyard. This is no longer an unusual event. However, the next day, again while breakfasting, I saw a large fox scurry across our yard. I only recall one other time seeing a fox in our yard in our nearly half century living in our present home. The following day, the wildlife parade continued when there was a rabbit happily eating clover in our yard. Rabbits are not unusual.
When we moved into our house in 1965, it was also not unusual for raccoons in our area to tip over garbage cans and we resorted to bungee cords to secure them from those marauding scavengers. However, for the past couple of decades or so, I've seen no evidence of raccoons and I stopped making any effort to secure the garbage cans. But, a couple days after the rabbit sighting, I was backing the car out of the garage and heard a thump. I'd bumped into our garbage can, which had been knocked over and one of the garbage bags chewed open by what I'm reasonably certain was a raccoon. They're back!
Appropriately, a couple of weeks ago, I watched a PBS Nature program on raccoons to see what these masked marauders are up to these days. I learned that the raccoon's original habitat was in the tropics but over the course of time they have migrated up into northern climes as far as Alaska. There were apparently no raccoons in Japan until relatively recently. Thanks to a fictional raccoon character, the Japanese fell in love with the cute animal and started importing raccoons as pets. Well, the critters weren't as lovable in person and were turned loose into the wild. The raccoons multiplied and found wooden temples particularly to their liking and soon these temples were being ravaged by the raccoons, their urine and feces contributing to decay of these structures that had survived for centuries and are still being used by Japanese monks. Now there's a campaign to kill the pesky creatures, with some ten thousand being killed every year! Raccoons were also introduced into Europe and the program cited Germany has having a problem with damage to structures caused by raccoons.
I knew that raccoons could climb but didn't realize how agile they truly are, shinnying up downspouts with alacrity. A particularly fascinating segment of the program followed a raccoon mother with her brood of youngsters. The young raccoons typically stay with the mother for more than a year while she teaches them the lessons they need to survive. (The raccoon father apparently takes off and has no role in the youngsters' upbringing.) This particular mother found a building (probably a barn or garage) with large doors that were not completely shut, thus providing a space at the top for entrance into the structure. The mother took her brood up to the roof and then demonstrated how to shrink her abdomen so as to squeeze into the small opening into the structure. After each one of her kits had squeezed inside, she would pop up looking for the next one to help inside. One of them fell off the roof and she came outside and down to pick up the clumsy one and put it back on the roof, where it finally managed to squeeze itself inside. It's worth watching if you get on the PBS Web site.
The main subject of the TV program was the adaptation of raccoons to life in large cities such as Chicago, New York and Toronto, Canada, which has one of the largest raccoon populations. In Toronto, scientists have tagged and followed raccoons to get some idea as to how wide ranging the creatures are. What they found was that the territory of the raccoon is only an area of about three blocks radius and the raccoons seem to have sensibly developed an aversion to crossing major highways. The city raccoon has truly adapted well to city life and the program raised the question as to whether or not we humans, by allowing the critters to live in our cities, are promoting the evolution of smarter raccoons. The thought occurs to me that, hey, what would happen if some raccoon mutated to have an opposable thumb? Those five little fingers are already able to grasp doorknobs and the like. With city smarts and an opposable thumb, who knows what these little guys and gals could accomplish? Could they take over the world when we humans go extinct?
Actually, for this column I had planned to write about evolution, having read a Perspective by Michael Benton on a paper by Michael Lee and coauthors in the August 1, 2014 issue of Science on how dinosaurs evolved to give rise to birds. Up until about twenty years ago, one of the key features distinguishing birds from other animals was feathers. However, we now know that dinosaurs had feathers at least 50 million years before the first bird, Archaeopteryx, arrived on the scene about 150 million years ago. It weighed about two pounds and was under two feet in length.
What led to birds? The answer, according to Lee and coworkers, was a continuing and, in geological terms, rapid process of miniaturization and development of birdlike features such as short snouts, enlarged eyes and brains. The researchers plotted the length of the femur (thighbone) in the dinosaur lineage leading to the bird and concluded that the body size decreased from 163 kilograms down to 0.8 kilogram in a mere 50 million years. Dinosaurs had been jumping, gliding and parachuting but it seems that life in trees may be the feature driving the miniaturization that led finally to free flying creatures, birds.
Speaking of birds, I've often written about studies showing that these winged creatures are not "bird-brained" in the sense that it often has been used. Western scrub jays, for example, have been shown to remember past events and cache food for future use, anticipating they will be hungry in the future. In the September issue of Scientific American, Jason Goldman has a brief item on an experiment done by Arii Watanabe of the University of Cambridge. Watanabe wanted to see if the scrub jay is aware that it is planning for its future. In a neat experiment, Watanabe had two researchers hide tasty morsels, wax worms. One of the researchers had four open cups in front of him so he could hide the worm in any of the four cups. The other researcher had three covered cups and only one open cup in front of him. Obviously, he could only hide the worm in the open cup.
If the scrub jay is smart, it would soon realize that it would be best rewarded in the future by watching the 4-open-cup fellow, knowing the other guy could only put the worm in the open cup. Watanabe had five scrub jays participate in the experiment and the jays lived up to expectation. They spent more time watching the fellow hiding the worms in the four open cups.
Finally, on the subject of evolution, the September issue of Scientific American devotes most of the issue to the subject of the evolution of us humans. "Evolution, the human saga" is the theme of the issue. With recent findings of new and more complete skeletal fossils, it is clear that much more work is in the offing to detail our increasingly complex evolutionary past. One of the articles discusses the question as to whether we humans are still evolving and the answer is yes. Let's hope that somewhere in the future the human brain evolves in some way that promotes a realization that we on this planet need to work together to save our environment and ourselves from extinction!
Next column will be posted, hopefully, on or about October 1, 2014.
Allen F. Bortrum
|
