We’re going to see mass primate extinction in the next few decades if we don’t take conservation efforts more seriously now, say researchers who conducted the most comprehensive review of primate status so far.

For a study published today in the journal Science Advances, scientists combined information from the Red List of endangered species, United Nations databases, and scientific literature to analyze the state of over 500 primates (which include monkeys, apes, and even lemurs) around the world. By taking into account everything from trends in forest loss to the impact of illegal trade to agriculture, they found that 60 percent of primates are at risk of extinction, and about three-fourths have declining populations.

Though hunting and the illegal pet trade are partly to blame, the biggest reason for the declining populations is human activities. Logging, producing palm oil, mining, and drilling all wipe off the habitat of these species, which pushes them closer to extinction.

It’s important to find ways to reduce these impacts, and that means looking beyond just environmental factors, say the researchers. For example, habitat loss is more common when the local communities are living in poverty and their populations are growing quickly. So addressing those issues can also help primate conservation.

Primates are heavily concentrated in a few regions: Madagascar, the Democratic Republic of Congo, Brazil, and Indonesia. These four areas have two-thirds of the world’s primates, so it makes sense to focus on these areas if we want to be most effective at saving these animals.