why is the crow's chest white?
The San of the Kalahari Desert has many tales about animals, and here are two of that short stories:

The white patch or collar around the neck of the African Pied (White breasted) crow is said to have been made by a lump of fat tied on by Bushman wives.

The women attached the fat before sending the bird to look for their husbands, if they were late returning after a long day's hunting.

Whether the fat was to sustain the crow on his long flight, or to restore the husbands upon being found is not quite clear, but it has certainly left the crow with an indelible stain on his chest!

The story of how the snake lost his legs:

In the story of how the snake lost his legs, the moon is portrayed as a sympathetic deity who looked into the future, and saw that a terrible drought was impending.

She called to Mantis. 'You must take your wives and children and all the birds and animals and move from this area, for soon there will be nothing here but a desert,' she warned him.

So Mantis told everybody, and all the animals packed up and trekked away to other green places with water.

So, all the animals moved away, except the snake, which in those days had legs like other animals. He was lazy and quarrel-some, and did not believe Mantis. 'No, I will stay here. Your drought will not worry me,' he said.

But soon, when no rain fell and the grass begin to shrivel and all the little fat frogs hopped away. With no fat little frogs to eat, the snake grew thin and hungry and decided to follow the other animals.

By then, however, the land had become a desert of hot loose sand, and with every step, the snake sank into the hot sand. Soon he was very tired from struggling through the loose sand

At last, in desperation, he cried: 'Oh Moon, I am ashamed of myself. Please save me from the sun and hot sand, and I will change my ways.'

The moon took pity on the creature, and in a moment the snake found that his legs had shrunk away, and on his gleaming stomach skin he could glide easily across the hot sand without sinking into it as before.

Whether the snake really did change his ways, when he had found his way out of the desert, we are not told.

But in view of the general feelings about these reptiles, I think it is doubtful!