About 55 million years ago, tiny shrew-like mammals began combing the forest canopies in search of food. These were the precursors of primates, fruit foragers whose survival depended on swift movement through the trees, deft hands and acute vision. The vision thing is especially important, because as our ancestors strengthened their ability to see in the dimensions required for canopy life, they developed color vision, a rarity among mammals. This allowed them to perceive what birds and insects had long known: that among the leaves were bright fruits and flowers, wondrous delicacies that could keep them alive.
Eventually, these early frugivores became omnivores and evolved into us. We developed language and culture and intercontinental ballistic missiles, but we never really lost our reliance on vision. Today, humans favor sight well above any other sense, including common. “Seeing is believing,” we say, gluing ourselves to a global television industry whose revenue topped $265 billion last year. We can distinguish 10 million colors, their impact and import hard-wired into our shrewd minds.
Unfortunately, this over-reliance on sight makes us more susceptible to invisible dangers. This issue’s cover story is about one such phenomenon. Visually, Coeur d’Alene Lake lives up to its reputation as the gem of Idaho. It is long and deep and lovely, with popular beaches and a tourism industry that relies on the beauty of bald eagles and chinook salmon. What we can’t see, Associate Editor Emily Benson writes, is the danger below the surface — a potent concoction of mine-drainage toxins, locked into the bed of the lake by a fluke of chemistry. Under the wrong circumstances, the lake could turn deadly. But the people of Idaho either can’t or won’t face this danger, at least not yet.
Other stories in this issue warn of hard-to-see hazards, including, it seems, our own government, so fervently dedicated to obfuscation. With the help of diligent Freedom of Information requests, editorial fellow Jessica Kutz has begun investigating an Interior Department program that has operated with little oversight or transparency, as rangers are moved from parks and refuges to patrol the U.S.-Mexico border. And writer Gabriel Furshong reminds us of the power of self-delusion — another vision problem — and asks why Montanans are so enamored of their vigilante origins.
Meanwhile, of course, the greatest danger continues to grow, out of sight and out of control. In May, carbon dioxide in the atmosphere reached 415 parts per million. If we don’t act, we’ll soon have a planet that hasn’t been this warm for hundreds of millions of years — well before those bright-eyed shrews took to the trees and started all this trouble.
This article appeared in the print edition of the magazine with the headline Out of sight, out of control.
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