Long Horns Win: Selection in action—Attacks favor spike length for lizards

A quirk in a bird’s hunting behavior has given scientists a rare chance to measure an evolutionary force in action in the wild.

GET THE POINT? A flat-tailed horned lizard assumes a defensive posture, ready to snap its spiky head backward and stab an attacker trying to grab its body. Young

When a loggerhead shrike catches a lizard, the bird often impales it on a thorn or a spur of barbed wire and then leaves the carcass hanging, explains evolutionary biologist Edmund D.