THE OUTSIDE STORY: Raccoons: It's all in the hands
Harry Houdini was a great break-out artist: Handcuffed, straight-jacketed, chained and submerged in water, he'd always emerge. Raccoons are famous break-in artists. No chimney flue, garbage can, or campground cooler is safe from their prying hands.
Like Harry Houdini, it's partly clever hand work that makes the raccoon so good and so bad. Raccoons have remarkably sensitive hands, with five long, tapered fingers and long nails. They lack thumbs, so can't grasp objects with one hand the way we can, but they use both forepaws together to lift and then acutely manipulate objects. Thanks to this tactile intelligence, raccoons are problem solvers that adapt easily to cities, suburbs, and other manmade habitats.
There's a myth that raccoon wash their food. (Our North American raccoon's species name, lotor, means washer in Latin.) But what they're doing when they wet and rub an object is "seeing" it; it's thought that water contact increases a raccoon's tactile ability. When a raccoon wets and handles a crayfish, stone, worm, or clam, he's gathering information: nearly two thirds of the sensory data that he's processing comes from cells that interpret various types of touch sensation. In other words, touch is as important a sense as hearing, smell, and sight.
Raccoons are omnivorous, which many researchers believe has pushed raccoon brain development. Every object they come across has the potential to be food: this drive to acquire a wide variety of foods, scientists believe, has driven human brain development as well. As every teacher knows, children learn by touch, whether it's building blocks or bouncing balls, and in cognitive development the sense of touch is vital to developing abstract understanding.
How did raccoons develop those incredible hands? They evolved around river and lake banks in South America where they had to use their forepaws to find food hidden under water or buried in mud and silt. The fingers of a raccoon's forepaws are well-padded. Each has some four to five times more mechanoreceptor cells (cells adapted to detect mechanical stimulus, such as changes in pressure) than are found in most mammals. Only humans and other primates have similar numbers.
So raccoons have this enormous ability to sense with their forepaws and a brain that's able to interpret and store vast amounts of touch sense information. They're omnivorous, curious, smart, practically fearless, and they have great memories. So, why, I wonder, haven't they learned how to open a simple barrel latch? Let me explain.
For over 30 years I've watched raccoons make their evening rounds to the primitive campsites on Cumberland Island, a national park at Georgia's coastal border with Florida. Cumberland offers a welcome escape from mud season, and I look forward to making the trip there each year. There are miles of uninhabited beach, a large live oak forest and robust populations of feral horses, migrant birds, wild boar and armadillos.
Raccoons have all kinds of natural foods at their disposal, from oysters and fish to mast crops and crabs. Why they prefer boxes of Saltines and hamburger buns to fresh oysters is beyond me. But they will spend hours trying to obtain camper food, often successfully.
Raccoon-proof containers at each campsite on the island consist of four foot square plywood boxes with sides screened using small-mesh hardware cloth. The boxes sit on posts five feet high. The front of each box is hinged and locked with a simple sliding barrel mechanism. I have witnessed raccoons hanging for hours from the wire mesh sides, poking their fingernails through the fine mesh (the defense against that is to line the inside of the box with cardboard). But I have never seen or heard of a raccoon opening a simple barrel latch. Why haven't they figured it out?
Rangers who have been dealing with raccoons for years have their theories. Some think it's the lack of an opposable thumb. Others say that because it's a two-step process, raccoons simply can't manage it through trial and error. I think it's only a matter of time before they slide open the barrels and we have to change the locks.
Tim Traver is an author and freelance writer who previously served as executive director of the Upper Valley Land Trust and co-directed the social service organization COVER Home Repair. The illustration for this column was drawn by Adelaide Tyrol. The Outside Story is assigned and edited by Northern Woodlands magazine and sponsored by the Wellborn Ecology Fund of New Hampshire Charitable Foundation: firstname.lastname@example.org
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