If you want to capture something wolflike, it’s best to embark before dawn. So on a morning this January, with the eastern horizon still pink-hued, I drove with two young scientists into a blanket of fog. Forty miles to the west, the industrial sprawl of Houston spawned a golden glow. Tanner Broussard’s old Toyota Tacoma bumped over the levee-top roads as killdeer, flushed from their rest, flew across the beams of his headlights. Broussard peered into the darkness, looking for traps.