ELEPHANTS ARE EVOLVING WITHOUT TUSKS TO SURVIVE POACHERS

Many of the elephants wandering Mozambique’s Gorongosa National Park these days are tuskless.

From 1977 until 1992, the country underwent a brutal civil war. Due to the conflict, about ninety percent of the elephants that once existed there were poached for their ivory, which helped fund weapons and feed soldiers.

Gorongosa’s tuskless elephants developed a biological advantage as a result of the poaching. According to recent figures, one-third of the generation of females born after the war ended never grew tusks – something that would normally only occur in 2 to 4 percent of female African elephants.

Elephant behavior expert Joyce Poole, who studies the park’s pachyderms, says that decades ago, some 4,000 elephants lived in Gorongosa. Following the civil war, those numbers tragically dwindled into the triple digits. Yet-unpublished research compiled by Poole shows that 51 percent of the 200 known adult females (aged 25 or older) that survived the war are tuskless. Of the female elephants born since the war, 32 percent have no tusks.

Poole, who serves as scientific director of a nonprofit called Elephant Voices, explains that male elephants have bigger and heavier tusks than females of the same age. She continues: “But once there’s been heavy poaching pressure on a population, then the poachers start to focus on the older females as well.” The resulting older age population of elephants will, therefore, consist of a high proportion of tuskless females.

Elephant poaching remains a huge problem throughout parts of Africa – it’s estimated that on average, an African elephant is killed every 15 minutes. It’s no surprise, then, that similar shifts among female survivors and their daughters have occurred in countries other than Mozambique that also have a history of substantial ivory poaching. The effect has been particularly extreme in South Africa – in the early 2000’s, 98 percent of the 174 females in Addo Elephant National Park were reported to be tuskless.

In some heavily-hunted areas, such as southern Kenya, poaching has led to reduced tusk sizes. According to a 2015 study by Duke University and the Kenya Wildlife Service, male survivors of a period of intense poaching had tusks about a fifth smaller than average, while females had tusks about one-third the normal size. This pattern continued – offspring born after 1995 had tusks between 21 and 27 percent smaller than elephants in the 1960’s.

Elephants without tusks are surviving and appear to be healthy, according to Poole, but the work they do with their tusks is part-and-parcel to their everyday lives and vital to the well-being of many smaller species, who rely on elephants to dig holes for water and topple trees over for shelter.

While measures are being taken to reduce the global demand for ivory, such as ivory bans in the U.S. and China, it’s unclear how long it will take for elephants with high levels of tusklessness to recover. One thing remains clear: when it comes to saving these beautiful, gentle giants from extinction, time is of the essence.

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Under poaching pressure, elephants are evolving to lose their tusks

THE OLDEST ELEPHANTS wandering Mozambique’s Gorongosa National Park bear the indelible markings of the civil war that gripped the country for 15 years: Many are tuskless. They’re the lone survivors of a conflict that killed about 90 percent of these beleaguered animals, slaughtered for ivory to finance weapons and for meat to feed the fighters.

Hunting gave elephants that didn’t grow tusks a biological advantage in Gorongosa. Recent figures suggest that about a third of younger females—the generation born after the war ended in 1992—never developed tusks. Normally, tusklessness would occur only in about 2 to 4 percent of female African elephants.

Decades ago, some 4,000 elephants lived in Gorongosa, says Joyce Poole—an elephant behavior expert and National Geographic Explorer who studies the park’s pachyderms. But those numbers dwindled to triple digits following the civil war. New, as yet unpublished, research she’s compiled indicates that of the 200 known adult females, 51 percent of those that survived the war—animals 25 years or older—are tuskless. And 32 percent of the female elephants born since the war are tuskless.

A male elephant’s tusks are bigger and heavier than those of a female of the same age, says Poole, who serves as scientific director of a nonprofit called ElephantVoices. “But once there’s been heavy poaching pressure on a population, then the poachers start to focus on the older females as well,” she explains. “Over time, with the older age population, you start to get this really higher proportion of tuskless females.”

This tuskless trend isn’t limited to Mozambique, either. Other countries with a history of substantial ivory poaching also see similar shifts among female survivors and their daughters. In South Africa, the effect has been particularly extreme—fully 98 percent of the 174 females in Addo Elephant National Park were reportedly tuskless in the early 2000s.

“The prevalence of tusklessness in Addo is truly remarkable and underscores the fact that high levels of poaching pressure can do more than just remove individuals from a population,” says Ryan Long, a behavioral ecologist at the University of Idaho and a National Geographic Explorer. The “consequences of such dramatic changes in elephant populations are only just beginning to be explored.”

Josephine Smit, who studies elephant behavior as a researcher with the Southern Tanzania Elephant Program, says that among the female elephants she tracks at Ruaha National Park, an area that was heavily poached in the 1970s and 1980s, 21 percent of females older than five are tuskless. As in Gorongosa, the numbers are highest among older females. About 35 percent of females older than 25 are tuskless, she says. And among elephants ages five to 25, 13 percent of females are tuskless. (Smit, a doctoral candidate at the University of Stirling, in Scotland, says the data have not yet been published, though she presented the findings at a scientific wildlife conference last December.)

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