The Shark and the Jellyfish: More Stories in Natural History

Sky Walkers

49 Sky Walkers The margay walked just above the ground, on a low branch so thin it quavered with her every step. Her legs flexed and her long tail switched from side to side to counter the swaying; she compensated so well that her head glided as steadily along as if she were on solid ground. She was an acrobat, lithe and sure, as accomplished a hunter in the trees as on land. She could hang from one back foot like a monkey as she negotiated the scaffolds of her world. When she paused to scan the streamside just below, the pattern of leopard rings on her coat merged with the network of twigs and shadows around her, and she faded into the background. She scanned the tropical forest understory beyond the maze of branches, but her gaze was drawn back to the limb just before her. Revealed there was what looked like the head of an insect floating in the moss—an oblong visage from which grew paired fronds that could have been antennae above a glossy black eye spot. A body was not apparent behind this head—it appeared to be attached to the finely veined sheath of a fallen leaf, which was overlain with the common blotchy texture of the moldering forest floor. But parallel to this leaf was a long shank ribbed in a herringbone design. As the margay drew closer to study the scene, she detected the faintest motion—the long appendage had tightened. Her eyes flashed and she pounced, moving faster than she could think, but pinned only moss between her claws. The hopper had launched reflexively, accelerating to a speed that would cover three meters in a second—faster than a cat’s eye could follow. Ten centimeters into its flight, it caromed against a twig. The stunning force of the collision would have incapacitated most creatures, but the grasshopper was built like a bullet with a helmet for a head, and the impact only set it spinning. It tumbled through the air with six legs spread in all directions, so even though it landed awkwardly on its back, it had one foot in position to grasp the bark and right itself. It gathered its grip, cocked its jumping legs, and hurled itself into the air again, all in less time than it took the cat to dive from the branches and pounce on the spot. The cat stood with one paw held up at shoulder height, her eyes track- 50 ing the hopper’s crazy trajectory. The insect ricocheted back and forth, disappearing along random paths, somersaulting through the air until it touched down, found its purchase, then sprang again twice, three times. It bounced here and there, finally launching into an arc that would land it in the water. This was an opportunity for the cat, who knew that an insect trapped on the surface is easy prey. The world spinning in the grasshopper’s eyes was dominated by a hemisphere of greatest brightness—sky light. Now a counterbalancing light entered his vision from another direction, with the same hue as the sky but only half as bright—polarized, reflected light. He deduced that he was descending over water. So he opened his wing covers and spread black and orange wings that rippled in the airstream until they slowed his tumbling descent. He rolled level and rose under slower but controlled flight, headed away across the stream. A jacamar perched twenty feet above the scene heard the heavy insect flying toward the brush on the far shoreline. But before she could take flight in pursuit, the display of bright wings disappeared—as though a branch had intervened in her line of sight. Her gaze tracked the flight path, but the banner of the insect’s colors did not emerge back into view. She knew that the hopper must have touched down and folded its wings in the same motion. It had vanished right before her under camouflaged wing covers snapped shut so quickly that she had not been able to mark its location . She considered descending to hunt through the general area, but the proximity of the cat dissuaded her. At the water’s edge the margay stood watching her meal sail out of reach. She turned to pick the driest course back along the shore. But before she could take a step she was startled when the stone she was about to walk on shot off across her path. The...