Vrishakapi is the name of a tawny yellow bull monkey mentioned in the Rig Veda. Some scholars are of the view that the mentioning of the Vrishakapi is an indirect reference to Hanuman in the Vedas.
In Rig Veda, wife of Indra complains that a huge monkey has stolen her husband’s portion of the Vedic offerings. Only one specific hymn mentions about the naughty monkey.
In Harivamsa, Vrishakapi is identified with the 11th form of Rudra. Some scriptures indicate that Hanuman was the 11th avatar of Rudra.
The name is also found in the Mahabharata and in the Vishnu Sahasranama (thousand names of Vishnu). In both these holy texts, Vrishakapi is one of the names of Vishnu.