White-lipped peccaries travel in large packs throughout the forest. The hairy, pig-like creatures emit a distinctive musky smell that is not easy to forget, and play a crucial role in their ecosystems, dispersing seeds and creating habitats for insects and amphibians.

Now, though, the species is facing a crisis. A recent study published in the journal Biological Conservation finds that the territory roamed by white-lipped peccaries in Mexico and Central America has shrunk by as much as 87 to 90 percent from their traditional range, and 63 percent from previous estimates.

“It’s shocking for me how fast this population is declining compared to the last assessment,” said Harald Beck, chair of the peccary specialist group of the nonprofit International Union for Conservation of Nature. Dr. Beck was not involved in the new study but conducted a similar one in 2012 that found a habitat loss at the time of 21 percent. “We did not know it was that bad.”

It’s not clear exactly how many animals remain, because of the difficulty of counting them, said Daniel Thornton, an assistant professor at Washington State University, who led the research. The new study relied on camera traps and local experts to identify territory where the social creatures still roam.