DISCLAIMER: THIS POST IS MY OPINION ONLY. NOT TO HURT ANYONE.
Many Western scholars and Indian scholars with Western mindset tried to fix the age of Srimad Ramayana, to approximately the 5th to 4th century BC. They succeeded to some extent in making people believe this story
But, If we study Srimad Ramayana in depth, we will get a clue
उत्तमम् राक्षसावासम् हनुमानवलोकयन् |
आससादाथ लक्ष्मीवान् राक्षसेन्द्रनिवेशनम् || चतुर् विषाणैर् द्विरदैः त्रिविषाणैः तथैव च |
परिक्षिप्तम् असम्बाधम् रक्ष्यमाणम् उदायुधैः || Thereafter, Hanuma the glorious one neared and observed the best residence of Rakshasas and the house of Ravana, containing elephants with four tusks and also those with three tusks, those with two tusks and still not crowded. It was protected by soldiers bearing raised weapons. (Sundara Kanda 9th Sarga 4 - 5 Slokas)
Here, Sage Valmiki describes elephants with four tusks and also those with three tusks and those with two tusks.
Modern anthropologists say that elephants with four tusks existed 12-1.6 million years ago. Referred to as gomphotheres, they were widespread in North America during the Miocene and Pliocene epochs, 12-1.6 million years ago. Most had four tusks, and their retracted facial and nasal bones prompt palaeontologists to believe that gomphotheres had elephant-like trunks.
Hence, we can infer that Srimad Ramayana was written 16 lakh or 1.6 million years ago and not 5th to 4th century BC.
From this it is very clear that RAMAYANA happened 1.6 million years ago.
WHO ARE VANARAS?
Vanaras were as described in ramayana are monkey like humans who had the ability to create fire, build bridges, fight, even read and write in some cases(mentioned clearly in Ramayana that only lord hanuman and some royal family were able to talk and study). Hence by seeing all this we can say that vanaras had the same ancestors as the homo sapien and they were very close to humans. We can say they were somewhere near to the homo erectus. Who were exactly there in this world 1.6 million years ago. Hence we can guess and say vanaras were homo erectus. We can also compare the pics of homo erectus with pics of vanar sena. - 2 minutes ago