Star Born by Andre Norton

Raf leaned back against the wall. Long since the actions of the aliens in the storage house had ceased to interest him, since they would not allow any of the Terrans to approach their plunder and he could not ask questions. Lablet continued to follow the officer about, vainly trying to understand his speech. And Hobart had taken his place by the upper entrance, his hand held stiffly across his body. The pilot knew that the captain was engaged in photographing all this activity with a wristband camera, hoping to make something of it later.

But Raf's own inclination was to slip out and do some exploring in those underground corridors beyond. Having remained where he was for a wearisome time, he noticed that his presence was now taken for granted by the hurrying aliens who brushed about him intent upon their assignments. And slowly he began to edge along the wall toward the other doorway. Once he froze as the officer strode by, Lablet in attendance. But what the painted warrior was looking for was a crystal box on a shelf to Raf's left. When he had pointed that out to an underling he was off again, and Raf was free to continue his crab's progress.