Physiology

"On those sounds being heard the down of Bhima's body stood on end; and he began to range that
plantain wood, in search of those sounds. And that one of mighty arms saw the monkey-chief in the
plantain wood, on an elevated rocky base. And he was hard to be looked at even as the lightning-flash;
and of coppery hue like that of the lightning-flash: and endued with the voice of the lightning-flash; and
quick moving as the lightning-flash; and having his short flesh neck supported on his shoulders; and
with his waist slender in consequence of the fullness of his shoulders. And his tail covered with long
hair, and a little bent at the end, was raised like unto a banner. And (Bhima) saw Hanuman's head
furnished with small lips, and coppery face and tongue, and red ears, and brisk eyes, and bare white
incisors sharpened at the edge.' And his head was like unto the shining moon; adorned with white teeth
within the mouth; and with mane scattered over, resembling a heap of asoka flowers.

Vana Parva: Section 145