Gilberto Pozo, a biologist, was monitoring a small forest in the southern Mexican town of Cunduacán in early May when two mantled howler monkeys fell from a tree in front of him with a thud.
“They were dehydrated and received treatment,” he explained. “But they didn’t survive.”
At first, Dr. Pozo and his team at Cobius, a nonprofit conservation group, thought the monkeys had been overcome by smoke from fires set by farmers clearing land nearby.
But as temperatures rose above 100 degrees Fahrenheit in recent weeks, dozens of reports of dead monkeys began to surface. Residents discovered groups of 10 or more dead at a time, many of whom also showed signs of dehydration. As of Wednesday, 147 monkeys had died in the southern Mexican states of Tabasco and Chiapas.
The deaths of dozens of howler monkeys in Mexico could be the latest sign of the danger extreme temperatures pose to wildlife around the world. As global temperatures have broken records, scientists have recently documented the deaths of Amazon dolphins and massive bleaching of the world’s coral reefs.
“Animals send us a warning, because they are sentinels of the ecosystem,” Dr. Pozo said of the monkeys. “If they’re not doing well, there’s something going on.”
Scientists investigating the deaths still don’t know exactly what caused them. But they hypothesize that warmer temperatures may have combined with a confluence of other factors – including fires, deforestation and logging – that trapped the monkeys in smaller forest areas, with little shade, food or water. Scientists have not yet ruled out the possibility of pathogens, but a recent autopsy on one of the monkeys showed no signs of influenza, including bird flu, or Covid-19, Dr. Pozo.
Mantled howler monkeys are one of the largest primates in Mexico and Central America, measuring about 25 inches on average. Covered in thick black fur, they are known for their deep, guttural calls. They eat fruits and leaves, which are also one of their main sources of water. Scientists suspect the drought has dried out the leaves and streams, making it harder for the monkeys to hydrate.
The species, found as far south as Peru, is considered vulnerable by the International Union for Conservation of Nature. But the Mexican subspecies is in worse shape and has been listed as endangered.
In Mexico, heat has helped trigger drought in much of the country and the capital is running out of water. Environmental changes have most likely put more pressure on Mexico’s small mammals. The state of Tabasco is home to much of the country’s livestock and is one of the most deforested states in Mexico. As farms have expanded in the region, the rainforests where the monkeys live have diminished.
“In general, howler monkeys are very resilient to these conditions and can survive for long periods of time,” said Liliana Cortés Ortiz, a primatologist at the University of Michigan and vice chair of the Primate Specialist Group at the International Union. for the conservation of wild species. Nature.
Videos showing large groups of dead monkeys on the ground, or local residents with the limp bodies of baby monkeys, have spread on social media in recent weeks. “Please, whoever is starting the fire, stop,” one person said in a video posted to Facebook.
The deaths prompted a response from President Andrés Manuel López Obrador on Monday, when he told reporters his government was studying ways to help. “It was very hot,” he said. “I’ve never felt it this bad,” during recent visits to some states, he added.
This is not the first time this species of howler monkey has been in trouble. In 2016, an equally hot and dry year, mass mortalities of howler monkeys were also reported in Nicaragua. At the time, scientists estimated that at least 280 animals had died in three months, although they could not identify the cause.
Now, area scientists are forming a working group to develop protocols outlining what people should and shouldn’t do if they find monkeys in distress. They are also trying to attract funds to conduct more research into the causes of deaths.
Dr. Cortés Ortiz said she is concerned about what might happen to other species that people are unlikely to notice.
Although species have evolved to adapt to different conditions, things are now changing “so quickly that it will be very difficult for many species to adapt,” Dr. Cortés Ortiz said. “There’s not enough time.”
For now, academic and nonprofit groups in Mexico are taking care of what monkeys they can find. More than a dozen are at clinics to be hydrated and treated. Some are recovering in the town of Cunduácan, where Dr. Pozo first saw animals falling from a tree. But on Wednesday, he said, “unfortunately, one of them passed away.”
News Source : www.nytimes.com
Gn world
