Vast swathes of the country have been sweltering in temperatures that have risen to over 50 degrees Celsius (122 Fahrenheit) in Rajasthan state.
The monkeys died in Joshi Baba forest range in Madhya Pradesh state where the thermometer reached 46 Celsius (114 Fahrenheit).
District forest officer P. N. Mishra said the primates were believed to have fought with a rival troupe over access to a water source.
“This is rare and strange as herbivores don’t indulge in such conflicts,” Mishra told NDTV network.
“We’re probing all possibilities, including the possibility of conflict between groups of monkeys for water… which led to the death of 15 monkeys from a 30-35-strong group of monkeys living in the caves,” Mishra was quoted as saying.
“Certain groups of monkeys which are large in number and dominate that particular part may have scared away the smaller group of monkeys from the water,” Mishra said.
An autopsy said heatstroke likely caused the deaths.
Tigers have also been reported to be moving out of forest reserves into villages in search of water, causing alerts.
Temperatures touched 50.3 degrees Celsius in the Rajasthan town of Churu last week, just shy of India’s record of 51 degrees.
The heatwave has exposed falling water levels in underground reservoirs and there have been a number of human deaths reported.
In Jharkhand state, a man stabbed six others after he was stopped from filling extra water barrels at a public tank, media reported Saturday.
On Friday, a 33-year-old man died after a similar fight in Tamil Nadu state.
The Indian peninsula has seen a drastic change in rainfall patterns over the past decade, marked by frequent droughts, floods and sudden storms.
In Uttar Pradesh state, 26 people died after freak dust storms, rain and lightning hit the northern plains on Thursday, officials said.
Kerala in the south got some respite from heat Saturday after annual monsoon rains arrived, more than a week later than expected.
Farmers across South Asia depend rely on the four-month monsoon season due to a lack of alternative sources of irrigation.
© Agence France-Presse