A monkey who was the foster-father of बालि and सुग्रीव . He was the king of किष्किन्धा . He had no issue for a long time. बालि and सुग्रीव were brought up by अहल्या at गौतम 's आश्रम . ऋक्सरजस् , with the permission of इन्द्र , went to the आश्रम and took बालि and सुग्रीव with him to किष्किन्धा . From that time, बालि and सुग्रीव remained with him as his foster-sons. (Uttara Rāmāyaṇa)

There is a story in वाल्मीकि रामायण , प्रक्षिप्त सर्ग , about the origin of this monkey.

Once when ब्रह्मा was in a state of meditation on the मेरु mountain, tears rolled down from his eyes and he gathered the tears in his own hands. From those tears, a monkey came into being. ऋक्षरजस् was that monkey.

One day, ऋक्षरजस् went to a lake to quench his thirst. Seeing his own image reflected in the water, he thought it was some enemy and jumped into the lake, to attack him. But he soon realized his mistake and returned to the shore. As soon as he came out of the water, he felt that he had become a woman. Seeing her fascinating beauty, इन्द्र and सूर्य were filled with lustful passion. Both of them had involuntary emission of semen. बालि was born from इन्द्र 's semen which fell on the head and सुग्रीव was born from सूर्य 's semen which fell on the neck of ऋक्षरजस् . Towards the end of the night, ऋक्षरजस् lost his female form and regained his former shape as a male. At once he took the two children with him to ब्रह्मा and told him the whole story. ब्रह्मा sent a messenger with ऋक्षरजस् and had him anointed king of किष्किन्धा . After the time of ऋक्षरजस् , बालि became king of किष्किन्धा .