CORVALLIS, Ore. (KTVZ) – In a first-of-its-kind study of aardvarks, Oregon State University researchers spent months in sub-Saharan Africa collecting droppings from the animal and concluded that the drying landscape is isolating them. could have implications for their long-term survival.
“Everybody’s heard of aardvarks, and they’re considered very ecologically important, but there’s been very little study of them,” said Clint Epps, an Oregon wildlife biologist. “We wanted to see if we could collect enough data to start understanding it.”
In a document just published in Diversity and Distribution, researchers used genetic information gathered from 104 aardvark feces samples to begin to understand their home range.
“In times of rapid environmental change, assessing and describing changes in the landscape where a species lives is important for informed conservation and management decisions,” said Rachel Crowhurst, a wildlife geneticist who works with Epps and co-authored the paper.
Aardvarks are nocturnal burrowing mammals that can weigh up to 180 kg. They have a long snout, similar to that of a pig, which they use, along with their claws, to locate and dig up ant and termite mounds. They are found over much of the southern two-thirds of Africa.
Despite the fact that they are often compared to pigs and South American anteaters, aardvarks are not related to them. Aardvarks are the only living member of the order Tubulidentata, and their closest relatives include golden moles, elephants, and cabbages.
The International Union for Conservation of Nature lists aardvarks in the category of “least concern”, in part because of the wide range of ecosystems they inhabit. However, little is known about current population trends or their actual distribution across the landscape. The Oregon State researchers believe the species has been understudied because it is nocturnal, difficult to trap and occurs at low densities in large and often remote landscapes.
These factors led Epps to undertake the first study of aardvark genetics in the wild and to develop non-invasive methods to do so. People have looked at aardvark DNA before for studies of mammalian evolution, but never in wild populations.
Epps learned to recognize aardvark tracks and droppings (which they bury) when he was working as a postdoctoral researcher nearly 20 years ago in Tanzania. In 2016, during a sabbatical, he returned to Africa for six weeks to see if he could spot signs of aardvark digging, track them through the bush and find their buried droppings.
“I wanted to work in an understudied system where anything I learned would probably be really new information for the scientific community,” Epps said. “I also wanted to work in large landscapes, on foot, alone or with a friend or with rangers when necessary, in protected areas, with minimal logistics and low cost.”
He learned how to find their droppings on that 2016 trip and returned for shorter trips in 2017 with graduate student Rob Spaan and in 2018 with Crowhurst.
They looked at eight protected and four privately owned areas in South Africa, two protected areas in Eswatini (formerly Swaziland) and one site in Kenya. They collected 253 stool samples and analyzed 104 that were of the highest quality for genetic information.
They then used the genetic information to infer aardvark distribution and movement across the landscape. For example, if genetic testing showed that faecal samples collected at different sites came from the same aardvark, they then used this information to determine the scale of individual movements.
In South Africa, the genetic information they collected suggested three regional divisions of aardvarks, indicating that the animals in the western, central and eastern regions of South Africa were somewhat isolated from each other. Individuals were found in multiple locations separated by up to 7 km, indicating that home ranges may be greater than previously determined, particularly in arid regions where food resources may be low.
Closely related individuals were located within 44 km of each other, and individuals less than 55 km were more genetically similar. So they discovered that aardvarks can disperse up to 55 kilometers from where they were born. Across the study area, genetic differentiation among individuals was greatest when intervening landscapes were drier, suggesting that movement through these areas is limited.
The researchers plan to continue the work and hope to perform genomic analysis on new samples and conduct fieldwork in a wider area of sub-Saharan Africa.
“Our initial findings suggest that climate change will increase habitat fragmentation and limit gene flow for aardvarks, particularly where rainfall is expected to decrease and temperature to increase,” Epps said. “With drought expected to increase in southern Africa under most climate change scenarios, the need for further research is clear.”
Epps’ other hope for further research: to see an aardvark in the wild. That goal eluded him.
The paper was also co-authored by Spaan and Matt Weldy of Oregon State and Hannah Tavalire of the University of Oregon.