There is an interesting story in the Hindu tradition that narrates why crocodiles and chameleons have rough and tough skin. The story is found in the Rig Veda. The story is associated with Apala, a ugly woman and Indra, the king of devas.
Apala was not a good looking woman. She had coarse and dry skin. Her husband rejected her due to her ugly skin.
She left home and reached a jungle. Here she made a hut and started a life away from the society. One day while searching for fruits and vegetables, she came across a strange plant. She picked up the tender part of the plant and started chewing it. It was the Soma plant.
Soma plant was considered highly precious by Devas and Indra, the king of gods, had a special liking for it. The accidental extraction of the Soma juice by Apala caught the attention of Indra.
He appeared before her and told her that she had extracted the Soma juice and offered her a boon for not sharing the secret.
Apala only had on thing to ask as boon and she asked Indra to make her beautiful. Indra agreed.
Indra pulled Apala through the hole of his chariot’s wheel three times and she appeared beautiful.
The skin that was shed from Apala the first time she was pulled through the chariot hole transformed into hedgehog.
The skin that was shed the second time became crocodile and the skin that was shed the third time became chameleon.