Natalie Angier in The New York Times:
Tom Vaughan, a photographer then living in Colorado’s Mancos Valley, kept a hummingbird feeder outside his house. One morning, he stepped through the portico door and noticed a black-chinned hummingbird dangling from the side of the red plastic feeder like a stray Christmas ornament. At first, Mr. Vaughan thought he knew what was going on. “I’d previously seen a hummingbird in a state of torpor,” he said, “when it was hanging straight down by its feet, regenerating its batteries, before dropping down and flying off.” On closer inspection, Mr. Vaughan saw that the hummingbird was hanging not by its feet but by its head. And forget about jumping its batteries: the bird was in the grip of a three-inch-long green praying mantis. The mantis was clinging with its back legs to the rim of the feeder, holding its feathered catch in its powerful, seemingly reverent front legs, and methodically chewing through the hummingbird’s skull to get at the nutritious brain tissue within. “It was staring at me as it fed,” Mr. Vaughan said. “Of course, I took a picture of it.” Startled by the clicking shutter, the mantis dropped its partially decapitated meal, crawled under the feeder — and began menacing two hummingbirds on the other side. “Talk about cognitive dissonance,” Mr. Vaughan said. “I always thought of mantises as wonderful things to have in your garden to get rid of bugs, but it turns out they sometimes go for larger prey, too.” "It gave me new respect for mantises,” he added.
Mr. Vaughan’s sentiment is echoed by a cadre of researchers who place mantises in a class of their own among the swarming Class Insecta, and who are discovering a range of skills and predilections that make mantises act like aspiring vertebrates. Praying mantises are the only insects able to swivel their heads and stare at you. Those piercing eyes are much like yours, equipped with 3-D vision and a fovea — a centralized concentration of light receptors — the better to focus and track. A mantis can jump as unerringly as a cat, controlling its trajectory through an intricate series of twists and turns distributed across its legs and body, all to ensure a flawless landing on a ridiculously iffy target nearly every time. The mantis appetite likewise turns out to leap and bound, and with scant regard for food-chain decorum. By the standard alimentary sequence, insects feed on plants or one another, and then birds hunt down insects. But just as there are carnivorous plants like the Venus flytrap, mantises prey on hummingbirds and other small-to-middling birds more often than most people realize.