Cunduacán, Mexico - Scientists and conservation groups in the south of Mexico are concerned that monkey populations could be at risk due to extreme heat and wildfires.

Over the last few weeks, people in and around the south Mexican town of Cunduacán have found groups of mantled howler monkeys dead beneath trees, sometimes in groups of ten or more. In total, local authorities have recorded 85 monkey deaths in the state of Tabasco.

After biologist Gilberto Pozo witnessed two monkeys fall from a tree in front of him, the first assumption was that local wildfires had caused the monkeys to die from smoke inhalation.

Yet, as more monkeys were reported dead over the course of the next few weeks, it became obvious that heatwaves with temperatures of over 100 degrees Fahrenheit were the more likely cause.

Per the New York Times, Pozo said that the monkey deaths were likely caused by extreme temperatures, adding: "The animals are sending us a warning, because they are sentinels of the ecosystem... If they are unwell, it’s because something is happening."

The state's Civil Protection agency later confirmed the cause of death as dehydration. Mexico's president, Andrés Manuel López Obrador, also commented on the issue in a press conference.

"I've been visiting the states for a long time and I have never felt it as much as now... So, yes, we have to care for the animals and yes, we are going to do it."

Considered a vulnerable species under the IUCN and endangered in Mexico, howler monkeys are threatened by a toxic combination of extreme heat and other human-related factors.