"Oh, they could be built to watch for them," said Huyghens, tolerantly. "But you'd have to swat for yourself. I prefer the bears." He led the way on. Twice Huyghens halted to examine the ground about the mountains' bases through binoculars. He looked encouraged as they went on. The monstrous peak which was like the bow of a ship at the end of the Sere Plateau was visibly nearer. Toward midday, indeed, it loomed high above the horizon, no more than fifteen miles away. And at midday Huyghens called a final halt. "No more congregations of sphexes down below," he said cheerfully, "and we haven't seen a climbing line of them in miles." The crossing of a sphex-trail had meant simply waiting until one party had passed, and then crossing before another came in view. "I've a hunch we've left their migration-route behind. Let's see what Semper tells us!" He waved the eagle aloft. Like all creatures other than men, the bird normally functioned only for the satisfaction of his appetite, and then tended to loaf or sleep. He had ridden the last few miles perched on Sitka Pete's pack. Now he soared upward and Huyghens watched in the small vision-plate. Semper went soaring. The image on the plate swayed and turned, and in minutes was above the plateau's edge. Here there were some patches of brush and the ground rolled a little. But as Semper towered higher still, the inner desert appeared. Nearby, it was clear of beasts. Only once, when the eagle banked sharply and the camera looked along the long dimension of the plateau, did Huyghens see any sign of the blue-and-tan beasts. There he saw what looked like masses amounting to herds. Incredible, of course; carnivores do not gather in herds. "We go straight up," said Huyghens in satisfaction. "We cross the Plateau here, and we can edge down-wind a bit, even. I think we'll find something interesting on our way to your robot-colony." He waved to the bears to go ahead uphill. They reached the top hours later, barely before sunset. And they saw game. Not much, but game at the grassy, brushy border of the desert. Huyghens brought down a shaggy ruminant which surely would not live on a desert. When night fell there was an abrupt chill in the air. It was much colder than night temperatures on the slopes. The air was thin. Bordman thought and presently guessed at the cause. In the lee of the prow-mountain the air was calm. There were no clouds. The ground radiated its heat to empty space. It could be bitterly cold in the night-time, here. "And hot by day," Huyghens agreed when he mentioned it. "The sunshine's terrifically hot where the air is thin, but on most mountains there's wind. By day, here, the ground will tend to heat up like the surface of a planet without atmosphere. It may be a hundred and forty or fifty degrees on the sand at midday. But it should be cold at night." It was. Before midnight Huyghens built a fire. There could be no danger of night-walkers where the temperature dropped to freezing.