âBruiserâ the bushbaby was killed by a dog in South Africa. He isnât alone
Many of the hallmarks of human civilizationâfrom roads and power lines to pet dogsâare taking a larger-than-expected toll on non-human primates living in Africa, according to two recent studies.
The findings result from a collaboration between 91´ŤĂ˝ and three South Africa-based institutions: the , theĚý and a conservation organization called the (EWT). They take an almost forensic look at what is killing wild animals in South Africa. The country is home to five species of non-human primates, including greater (Otolemur crassicaudatus) and southern lesser (Galago moholi) bushbabies. These primates spend most of their lives in trees, and some are so small they can fit in the palm of your hand.Ěý
In one study, scientists led by Birthe Linden at LajumaĚý in which non-human primates had been killed on roads or around power lines across the country. In a companion paper, the researchers Ěýdomestic dogs pose to the animals.

Samango or Sykes'Ěýmonkey (Credit: Public domain photo via )

A Samango monkey crosses a simple canopy bridge. (Credit: Birthe Linden)

Greater bushbaby seen crossing a canopy bridge at night. (Credit: Birthe Linden)
The research shows the threats facing the worldâs monkeys, apes and other non-human primates arenât always easy to see, particularly for lesser-studied animals like bushbabies.
âBushbabies, especially, are an example of species that may be having problems, but we donât know what they are until we go looking,â said Michelle Sauther, a co-author of the two studies and professor of anthropology at 91´ŤĂ˝.
For her, the results border on personal.Ěý
In the process of studying bushbabies in South Africa for more than a decade, Sauther and her colleagues got to know one male, in particularâa greater bushbaby with one eye who the team nicknamed Bruiser because he reminded them of an old prize fighter.
Then in 2019 Bruiser, who had bad and missing teeth, tried to move on the ground to reach a fig tree with easy-to-grab fruit. A pet dog found and killed him.Ěý
âThese are small stories,â Sauther said. âThey're not the big stories of conservation, but they really do matter, especially as we have no good data on bushbaby mortality and thus cannot easily judge their conservation status.â
Theyâre also small stories that likely touch almost all non-human primate species, not just in South Africa but across the continent.
âWe found that all South African non-human primates are in one way or the other impacted by human linear infrastructure, such as power lines or roads,â Linden said.Ěý
Roadkill on the rise
Linden, a primatologist from South Africa, first became interested in the hidden dangers facing primates on her daily drives to the University of Venda in South Africaâs Soutpansberg Mountains.
She kept seeing Samango monkeys (Cercopithecus albogularis) run over on the side of the road. These monkeys are listed in the Ěýas âvulnerable,â one step up from âendangered.â
âIt's one stretch where the road is quite close to indigenous forest, which is where Samango monkeys typically live,â Linden said.
She wondered if a lot more non-human primates could be dying as roadkill than researchers suspected. South Africa is home to more than 675,000 miles (1,090,000 kilometers) of roads and power linesâand the numberĚýkeeps climbing.
To explore this pervasive threat, Linden and her colleagues drew from a wide range of data sources. They include , a citizen science app released by the EWT that allows anyone in South Africa to upload reports of roadkill. In all, the team gathered 483 examples of primates killed on roads or around power lines, some dating back to the late 1990s. Species included the two bushbabies, Samango monkeys, chacma baboons (Papio ursinus) and vervet monkeys (Chlorocebus pygerythrus).
Next up, Frank Cuozzo of the Lajuma Research Centre and a research fellow at the University of Pretoriaâs Mammal Research Institute led the group in exploring a different kind of peril: domestic dogs. The researchers tracked down 13 reports of greater bushbabies like Bruiser killed by dogs in South Africa since 2014. In one case, humans intentionally released dogs to hunt down a bushbaby that had gotten too close to town.
âThese reports are clearly a sliver of whatâs actually happening,â said Cuozzo who earned his doctorate in biological anthropology from 91´ŤĂ˝ in 2000. âItâs happening in the towns and suburban areas, in the rural areas, the reserve areas, and itâs happening far more than anyone would think.â
Why did the monkey cross the road?
The researchers arenât sure how big of a dent roads, power lines and domestic dogs are making in non-human primate numbers in South Africa or surrounding nations. But they argue that these deaths are important to followâespecially for animals already struggling to survive amid climate change and habitat loss.
Wendy Collinson-Jonker, a co-author of the study on infrastructure andĚýa researcher at the EWT, noted these problems are widespread, but the fixes may be surprisingly simple.
, for example, that monkeys and other forest critters can hop across roads safely on âcanopy bridges,â such as a rope bridge hanging between trees.
Humans can also keep dogs away from primates by being careful to not leave food out, especially at night.Ěý
âWe know the solutions,â Collinson-Jonker said. âIt's a case of now getting them implemented.â
As for Bruiser the bushbaby, Sauther noted his story ended with a small bit of consolation. The teamĚýrecovered his body and collected X-rays that helped reveal a deeper picture of his more than a decade of lifeâdown to the arthritis building up between his joints that likely led him to climb down to the ground.
âWe were able to document his whole life story,â Sauther said. âWe knew him right to the end.â
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