How DNA left behind in the sand of South Africa led to the rediscovery of De Winton’s Golden Mole, a species lost to science for 87 years
By Kyrsten Stringer on November 29, 2023
Using new eDNA technology and a specially trained scent-detection dog, an intrepid team of scientists with Endangered Wildlife Trust (EWT) have uncovered important secrets hidden in the sand dunes of Port Nolloth, a seaport town on the northwest coast of South Africa. The team’s passion, creativity and determination has led to the exciting rediscovery of De Winton’s Golden Mole, the latest species to graduate off of Re:wild’s most wanted lost species list to a status of rediscovered.
“I think it's just fantastic that in 2023 we can still rediscover species,” says Cobus Theron, program manager at EWT. “All of our stories around conservation are doom and gloom. Here we have an opportunity to say that, actually, there are opportunities to make change.”
De Winton’s Golden Mole was last scientifically documented in South Africa—in Port Nolloth—in 1936, when Franklin D. Roosevelt was president of the United States; a species lost for almost a full century, of which there were no photographs, and limited information about its behavior, or how it differs as a species from other golden moles. As a family, the 21 known species of golden moles are generally small, blind, insect-eating mammals that are not actually gold in color. They owe their ‘golden’ name to the pearl-like iridescence of their fur, a beautiful little byproduct of the oil their body secretes to make it easier to “swim” through sand.
Yes, you read that right. Tracking golden moles is difficult in part because they live and travel underneath sand, navigating the world through sound and vibrations that tremble between sand grains. For fans of Frank Herbert’s Dune novels, it might be difficult to read a description of a golden mole without recalling the Shai Hulud of the sand dunes on Arrakis — but golden moles are not science fiction. They are tiny real-life curiosities, and an example of how weird and wonderful the wild on Earth is.
The first challenge: it is impossible to train a dog to track a scent there is no sample for. In the absence of De Winton’s Golden Mole, the team settled for the next best thing: they used the scent of other, more common, golden moles to help narrow down search sites. EWT trained a scent-detection border collie named Jessie to lay down on the ground to alert the team that she caught the scent of a familiar golden mole species. The team knew that Jessie wouldn’t be able to detect De Winton’s, but hoped that she might be able to rule out other more common species.
The second challenge: sand moves. Sand dunes shift with the wind and with time, which means that golden moles do not leave whole tunnels or burrows behind that make their presence more obvious. They tend to skitter 2 to 4 inches beneath the surface of the sand, where it is cooler, during the day. They navigate the world through sound, and the slightest vibrations in the grains disturb them, including humans walking on the sand overhead. It is usually only after the sun has begun to set that golden moles crawl into the open air, and leave hints of their presence behind them under cover of darkness, in the form of raised paths or collapsed sand pockets.
The third challenge: determining the positive identification of De Winton's Golden Mole without a historical sample, without a detailed description of how the species differs from other golden moles, and without DNA.
When they arrived at Port Nolloth, a heavy rainstorm had come through, which helped the team see fresh tracks and burrows of golden moles. Jessie did not signal for a scent she recognized. Because the team knew there were golden moles in the area, Jessie's lack of interest actually told them something else: there was a species here their scent-dog did not know, and she did not know De Winton’s Golden Mole.
The team collected more than 100 samples from the sand to take back to the lab for eDNA —short for environmental DNA— analysis. eDNA focuses specifically on the nuclear or mitochondrial DNA animals leave behind as they move through their environment, including hair cells, skin cells and scat.
By comparing multiple sequences of mystery DNA found at Port Nolloth to samples from De Winton's only ancestral cousin, Van Zyl’s Golden Mole, another Endangered species, the EWT team found that the eDNA belonged to a sister species of Van Zyl’s.
Although the eDNA didn’t match any other known species of golden mole, it still wasn’t enough evidence to declare De Winton’s Golden Mole rediscovered. The team didn’t have a full DNA sequence of De Winton’s Golden Mole to compare the results to.
Despite testing more than 100 soil samples and seeing tracks on the beach in Port Nolloth, the team accepted they would have to do more morphological and genetic analysis on the golden moles living on the beach.
The missing evidence they needed to finally unmask the mystery golden mole species in Port Nolloth unexpectedly became available in 2022. The Port Nolloth Museum had an old specimen of De Winton’s Golden Mole in its collection and a separate team of researchers had sequenced a number of its genes. When their results were published, the EWT team immediately compared them to the eDNA in the soil samples.
It was a match.
“It's been so exciting for me to make this discovery alongside a group of people with a shared interest and vision for golden moles to raise awareness about their presence, about their plight,” says Samantha Mynhardt, a conservation genetics researcher at the Endangered Wildlife Trust. “The other side is the importance of using eDNA as a method for studying these animals. I know from a research perspective and within the scientific community that the use of eDNA for detecting rare species is important and exciting.”
Based on EWT’s findings, it appears there may be a healthy population of De Winton’s Golden Mole in Port Nolloth. The team also detected the eDNA of Cape Golden Mole, Grant’s Golden Mole, and Van Zyl’s Golden Mole, a species of golden mole lost to science for 18 years, in the soil samples as well.
The EWT team is excited about what this rediscovery means for the future of conservation, and the role eDNA will play in that future for conservation in South Africa.
“It puts a focus on species that people walk over and don't even know that they're there,” says Esther Matthew, senior field officer at EWT. “A lot of the conservation focus is on the more charismatic and big animals that people see often, while the rare ones that probably need more help are the ones that need more publicity. It was very exciting to be part of a team looking for lost species. The cherry on the cake is finding one.”
The location where De Winton’s was found is currently not a protected area. The team at Endangered Wildlife Trust wants to change that. This particular stretch of western coast in South Africa is a hot area for development, and the De Winton’s habitat is threatened by the presence of large-scale diamond mines operating nearby.
An Environmental Impact Assessment (EIA) screening tool is available to developers in South Africa, enabling them to screen potential build sites for endangered species. The information EWT has been able to collect about De Winton’s Golden Mole and all of the other golden moles living in the area can be shared with that screening program to help protect them.
“We need to identify areas to focus our conservation [efforts] ... and secure protected areas to make sure there's still strongholds for these species,” says JP Le Roux, former EWT field officer.
Scent-dogs are going to help make that possible. To help find sites with thriving populations of De Winton’s Golden Mole, EWT intends to train a new scent detection dog to track De Winton’s Golden Mole exclusively, which will aid in the future protection of the wildlands they depend on. (Jessie, the dog originally helping the team, died from cancer in late 2021.)
The sand of Port Nolloth has not yet given up all of its secrets about De Winton’s Golden Mole. Several questions remain to be answered, waiting for the EWT team to uncover them. How far is De Winton’s Golden Mole distributed across the coast? How many are there? What are the best ways to ensure the protection and the survival of this rediscovered species?
“The amazing part for me is that it's been there all this time, and nobody knew,” says Le Roux. “Now we finally know."
Kyrsten Stringer is a Brand Content Manager for Re:wild specializing in storytelling techniques designed to immerse the reader in the narrative Kyrsten is passionate about breaking down barriers to nature through the power of inclusive language, and about the power of words to galvanize action in conservation — for wildlife and wildlands, for the ocean, and for people everywhere. Her home base is Saskatchewan, Canada.