The assessment of 504 primate species found that 60 percent are on track toward extinction, and the numbers of 75 percent are going down.

Agricultural expansion led to the clearing of primate habitat nearly three times the size of France between 1990 and 2010, impinging on the range of 76 percent of apes and monkeys.

By region, Madagascar and Southeast Asia have the most species in trouble. Nearly 90 percent of Madagascar’s more than 100 primates are moving toward extinction.

Primates also face serious threats from hunting, logging and ranching.

Gorillas, chimpanzees, orangutans — our great ape cousins teeter on the precipice of extinction. And it’s not much of a secret that we humans have had a lot to do with putting them there.

But what about the other primates? The news isn’t much better, it turns out.

According to a new study, 60 percent of primates — including drills and gibbons, lemurs and tarsiers, bush babies and spider monkeys — face the threat of extinction. Even those not in immediate danger of dying out are at risk, as the numbers of three-quarters of all primate species are trending downward.

“The figures suggest that we may be reaching a tipping point or perhaps we are already there,” said Alejandro Estrada, lead author of the study and a senior research scientist at the National Autonomous University of Mexico, in an email to Mongabay. He and 30 other primatologists published their research Wednesday in the journal Science Advances.

Estrada said that he and fellow author Paul Garber of the University of Illinois noticed that, for all the research on specific primates in specific areas, what was missing was a broader understanding of conservation and threats for all primates.

But that’s not an easy undertaking. Primates are a huge and diverse group with 504 species by the authors’ count. The only other mammal orders with more species are the bats and the rodents.

The team began by pulling together information from published research, the IUCN Red List, and UN databases to puzzle out where primate populations are headed and why.

The researchers tabulated the threats, statuses and conservation efforts for primates in 90 countries across Central and South America, Asia, mainland Africa, and Madagascar.

“What was surprising from our global analysis is that many species in the four regions are threatened and a higher number have their populations declining,” Estrada said.

For example, nearly 90 percent of Madagascar’s more than 100 primate species are threatened.