The threat of extinction has diminished the odds of spotting one of these wood-dwelling elephants in recent decades, according to a new IUCN Red List assessment of African elephants released Thursday. The Red List categorizes species by their risk of forever vanishing from the world. The new assessment is the first in which the conservation union treats Africa’s forest and savanna elephants as two species instead of one. Both are in bad shape. The last time the group assessed African elephants, in 2008, it listed them as vulnerable. Now it says savanna elephants are endangered, one category worse. The shy forest elephants have lost nearly nine-tenths of their number in a generation and are now critically endangered — just one step from extinction in the wild. Led by Dr. Gobush, the assessment team gathered data from 495 sites across Africa. A statistical model let them use the elephant numbers from each site to see broader trends for both species. 

“We essentially looked at data from as far back as possible,” Dr. Gobush said. The IUCN aims for three generations of data to get a full picture of an animal’s well-being. But for the long-lived elephants, that’s a challenge. The average savanna elephant mother gives birth at 25 years; forest elephant moms are 31 on average. Because the earliest surveys researchers could find were from the 1960s and 1970s, they could peer back only two generations for savanna elephants, and a single generation for forest elephants. Even during those few decades, the changes were drastic. The population of savanna elephants has fallen at least 60 percent, the team found. Forest elephants have declined by more than 86 percent. 

“That is alarming,” said Ben Okita, a Nairobi-based conservation biologist with Save the Elephants. Dr. Okita is co-chair of the conservation union’s African Elephant Specialist Group but did not work on the new assessment. Dr. Okita said that considering the two elephant species separately was helping to reveal just how bad things are, especially for the forest elephant. “The forest elephants, in most cases, have been largely ignored,” he said. Grouping the two elephants together probably masked just how bad things were for the forest elephant, he said. The IUCN made the change because in recent years, “It’s become clear that genetically these two species are different,” Dr. Okita said. The final piece of evidence for the conservation union was a 2019 study it commissioned that showed the two elephants only rarely reproduce with each other. It will be especially hard for forest elephants to bounce back, because of how long they wait to reproduce — six years longer than the savanna elephants. The IUCN assessment also found that 70 percent of forest elephants might live outside protected areas, leaving them especially vulnerable to ivory poachers.