Mato Grosso Titi Monkey

Mato Grosso titi monkey has lost habitat to deforestation in Brazil.

The Mato Grosso titi monkey was identified as its own species only four years ago. But it’s already one of the world’s most endangered primates.

Also known as the Groves’ titi monkey (Plecturocebus grovesi), the small monkey was described in 2019 by a group of researchers in the municipality of Alta Floresta, Mato Grosso, Brazil.1

Weighing only about 2 pounds, the monkeys are found in the Brazilian Amazon and where the Amazon overlaps with the Cerrado ecosystem, one of the most threatened areas in Brazil.2 The monkeys are just one of four species on the new “Primates in Peril” list of the 25 most endangered primates in the world.3

The list was launched at the recent 19th Congress of the Brazilian Society of Primatology. Brazil has more endangered primates than any other country on Earth.3

"It seems only fitting for this list to be launched today in Brazil, where not only do we have an incredibly diverse set of primates, but a passionate and growing group of Brazilian primatologists working on the animals’ conservation," Gustavo Canale, president of the Brazilian Society of Primatology and vice chair of the International Union for Conservation of Nature (IUCN) Species Survival Commission (SSC) Primate Specialist Group for Brazil and the Guianas, said in a statement.3

"We’re interested in sharing our experiences, advances, and conservation methods across regions to improve the knowledge of and situation for primates in Brazil and all around the world."

Threats From Deforestation

The newly recognized species has mostly gray fur on its head and back, a bright red-brown underside, yellow on its cheeks, and a black tail with a pale tip.1

It is monogamous and mates intertwine their tails and perform duets when they’re together. The male monkeys play a major role in taking care of babies.3

The main threat to species in the Brazilian Amazon is deforestation for cattle. Areas are often cleared for pasture and to grow crops such as soybeans. The Mato Grosso titi monkey’s habitat is in the area with the greatest deforestation.3

State legislators are also considering an ordinance that would no longer require landowners to protect 80% of native Amazon vegetation. If that passes, according to conservationists, many species in the area—including the Mato Grosso titi monkey—would face an even greater risk of extinction.3

"Although the fast-pace rate of deforestation in Mato Grosso imposes urgent action to the protection of Mato Grosso titi monkey, as an uplifting note, small populations may still be found surviving in forest fragments smaller than ten hectares," Canale tells Treehugger.

But that may not necessarily be good news. Canale points out that it's only been a short time since deforestation started so the effects may not yet be felt with the species.

"A plausible explanation to the presence of Mato Grosso titi monkeys living in tiny forest fragments, is the short time since deforestation in its distribution range," he says. "It may be too early to account for the consequences of habitat loss on the persistence of populations of Mato Grosso titi monkey." 

Conservation Opportunities

The “Primates in Peril” report is a collaboration by the IUCN SSC Primate Specialist Group, the International Primatological Society, and the conservation organization Re:wild. It describes the 25 most endangered primates from four regions: Africa, Madagascar, Asia, and the Neotropics.4

Currently, 43% of the world’s primates are listed as critically endangered or endangered on the IUCN Red List of Threatened Species.3 For the biennial report, members consider the degree of endangerment, as well as geographic and taxonomic representation to make sure primates are represented from different groups and all four locations. They also consider the likelihood that adding them to the list will urge further conservation steps.5

This 2022-2023 report lists six species from Africa, four from Madagascar, eight from Asia, and seven from the Neotropics. Seventeen of the species have been listed before, while eight are on the list for the first time.4

The golden-headed langur or Cat Ba hooded black leaf monkey (Trachypithecus poliocephalus), found only in northern Vietnam, has made it on all 11 reports. Listed as critically endangered, the monkey’s population has started to increase, due to conservation efforts.3

"Just because a primate ends up on the 'Primates in Peril' list doesn’t mean that the situation is hopeless," said Russ Mittermeier, a chief conservation officer with Re:wild and chair of the IUCN SSC primate specialist group.

"In fact, our goal with the report is to highlight those species, like the Mato Grosso titi monkey, where there are conservation opportunities. We hope this report helps spur the necessary resources, research and political will to reverse the decline of these species, those they share their home with, the ecosystems in which they live, and the health of the planet overall."

Mittermeier says there’s so much to find fascinating about the newly identified monkey.

It’s “a new species unknown to science until just a couple of years ago, and already endangered,” he tells Treehugger. “Also endemic to the state of Mato Grosso, a very important state for conservation.” 

Conservation plans for the monkey include additional research to learn more about its ecology and behavior, more work to look for other populations, and ecotourism to allow people to see the primate in the wild.5

"Due to the recent history of deforestation, several populations of Mato Grosso titi monkey may still be saved if a positive agenda for their conservation is put in place," Canale says. "This charismatic monkey may be instrumental to the safeguarding of the southern Amazon, which is crucial to mitigate the effects of global climate change."

Fact checked by Haley Mast