There is a nasty story in purana about their birth. Riksharaja an anthropomorphic money with human characteristics was born from Brahma’s thilak for the purpose of demolishing asuras in the forest. He got transformed into a beautiful woman when he entered a bewitched pond. As we discussed on other threads how the demi-gods have Rajas/Tamas gunas, Indra and Surya demi-god lust towards the lady (previous Riksharaja), sired Vali who is progeny of Indra, and sired Sugriva who is Progeny of Surya. Even  there are some court cases where brother married his brothers wife. So we call as an animal act. In-order to behave like animal, does one need to be an animal. No, Its the uncultured behavior’s. So Vali or Sugriva know all their relations, Vali just exhibited his uncultured behavior marrying Sugriva wife after driving him away.

This question of vaali and sugriva being monkey arises because there are no segment of people praying them. 

They are anthropomorphic, human bodies/mentalities with money features but very powerful than any humans or baboons in Kali Yuga, due to their father being Indra & Surya and mother transformed lady from  Riksharaja anthropomorphic monkey.

Thankyou swami for your views. My understanding is by knowing their extraordinary power vali did this fight and grabbing his brother assets and family as his greedy wishes. But one question is why Rama quoted killing vaali is valid being he is an Animal so hide and killing is valid.

Srimathe Rangaramanuja Mahadesikaya Namaha

Adhu romba simple Swamy.

You don’t ask an animal before hunting.

Dasanudasan