Eerie sight as wild monkeys drop dead from trees in Mexico

Monkeys are dropping dead from trees in Mexico in what one biologist has described as “animals sending us a warning”.

Monkeys are dropping dead from trees in Mexico.

More than 100 howler monkeys have reportedly died in the states of Tabasco and Chiapas in the south of the country during extreme heat.

They are believed to be dying from dehydration as temperatures have surpassed 40C, but authorities are also investigating malnutrition or fumigation of crops with pesticides.

A howler monkey is seen partially covered in lime spread by villagers over a mass grave where dozens have been buried in Comalcalco, Tabasco State, Mexico. Picture: Yuri Cortez / AFP

Biologist Gilberto Pozo had two monkeys fall from a tree right in front of him while in a forrest in the town of Cunduacán, Tabasco earlier this month.

They were dehydrated and received treatment, but didn’t survive.

“The animals are sending us a warning, because they are sentinels of the ecosystem,” Dr Pozo told The New York Times. “If they are unwell, it’s because something is happening.”

Local conservation organisation Cobius, which Dr Pozo is apart of, warned on social media that “massive deaths” of the monkeys were being reported and asked people who find dead monkeys to notify them or the authorities.

“If you see weak monkeys who are apparently suffering from heat or dehydration, please just try to lift a bucket of water with a mecate (rope) so they can drink water,” the Facebook post instructed.

A video showed more than five monkeys dead on the ground among dried leaves.

Veterinarian Victor Morato assists a howler monkey while it recovers. Picture: Yuri Cortez / AFP

Local veterinarian Víctor Morato told Wall Street Journal that within weeks at least 147 monkeys had died, and residents had stumbled upon bodies “that dropped dead from the trees”.

Dr Morato has treated those found alive but suffering at his animal hospital.

“It’s the saddest thing to have them stretch out their little hands to you as if to say, ‘Please help me, I’m dying,’” he told the publication.

“And more heartbreaking yet is to think that we humans have contributed to this disaster.”

When they faint from the heat they sometimes fall 20 metres, he added to AFP.

Several monkeys have arrived at his clinic with body temperatures of around 43C.

Authorities in Mexico are investigating the deaths but high temperatures affecting much of the country are believed to be the most likely cause. Monday. Picture: Yuri Cortez / AFP

Tabasco’s Civil Protection Institute said it was working with biologists and veterinary researchers to rescue and assist the howler monkeys in the region, “which are suffering the impact of the intense heatwave that affects the entire country”.

It said volunteers were providing the monkeys with water and fruit to keep them hydrated to withstand the heat.

Mexico’s environment ministry said it was working to determine the cause of death of the monkeys “and rule out any type of virus or disease”.

“To date, various hypotheses are shared about the reason for these deaths, such as heat stroke, dehydration, malnutrition or fumigation of crops with pesticides, so studies will also be carried out to determine the cause,” a statement said.

Food and water buckets placed by volunteers for howler monkeys in the branches of a tree in Comalcalco. Picture: Yuri Cortez / AFP

The mantled howler monkey (Alouatta palliata) is classified as vulnerable on the International Union for Conservation of Nature’s Red List of Threatened Species. The Yucatan black howler (Alouatta pigra) is considered endangered.

Mexican President Andres Manuel Lopez Obrador, who hails from Tabasco, said on Monday the heat was the worst he had known.

“Since I’ve been visiting these states I’ve never felt it as much as I do now,” he said at a press conference.