Probably a custom of the place.

Nothing queer about that, Olaf.

Why people have all kinds of pets--armadillos and snakes and rabbits, kangaroos and elephants and tigers." Remembering how the frog-woman had stuck in Larry's mind from the outset, I wondered whether all this was not more to convince himself than Olaf.
"Why, I remember a nice girl in Paris who had four pet pythons--" he went on.
But I listened no more, for now I was sure of my surmise.

The road had begun to thrust itself through high-flung, sharply pinnacled masses and rounded outcroppings of rock on which clung patches of the amber moss.
The trees had utterly vanished, and studding the moss-carpeted plains were only clumps of a willowy shrub from which hung, like grapes, clusters of white waxen blooms.

The light too had changed; gone were the dancing, sparkling atoms and the silver had faded to a soft, almost ashen greyness.