Comeback Kid: Search Dog Helps Find Golden Mole Feared To Be Extinct

The De Winton’s golden mole (Cryptochloris wintoni) was last sighted in 1937, leading to its classification as ‘Critically Endangered (Possibly Extinct)’ on the IUCN Red List of Threatened Species.

This small blind mole is particularly elusive. Difficult to see in the sand and leaving no visible tunnels as it borrows thanks to the oily secretions on its coat that allow it this animal to ‘swim’ through the sand, it was rarely seen even before its last known sighting 86 years ago. While the mole was spotted during field work in 2021, DNA sequencing has only now confirmed the finding, which was announced by the Endangered Wildlife Trust (EWT).

“​​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.”

This species had only ever been spotted in the small region of Port Nolloth in the Northern Cape province, South Africa. Additionally, they’re extremely sensitive to noise and vibration in the ground, meaning specimens would escape deeper underground as soon as they detected human presence. With no sightings, it was feared extinct – but scientists lacked the means to confirm whether that was the case.

That is, until environmental DNA and a scent detection dog called Jessie came into the picture.

Field Work

Environmental DNA (eDNA) refers to DNA samples recovered from the environment. It may come in the form of skin cells, faeces, urine or other secretions left behind by the animal. In January 2022, two separate studies confirmed that eDNA can even be extracted from airborne samples. This minimally invasive technique allows to confirm the presence a species in an area when the animal is particularly elusive.

As training Jessie to detect the specific scent of the De Winton’s golden mole was not possible, she was trained to detect the scent of other, more common golden mole species found in the area. This would help rule them out and narrow down search sites. The search team would then collect soil samples, from which eDNA could be extracted. It was a long, difficult process, which was subject of a research paper.

The breakthrough came as the team came across some mole tracks in the sand which Jessie did not react to as she would have if they had been left by mole species whose scent she was trained to detect. The team took samples, and encountered two specimens which they believed to be De Winton’s golden moles. However, one piece of the puzzle was still missing: the team needed some confirmed DNA from the species to compare their samples to.

Breakthrough

That chance came in 2022, when a team of researchers at the Port Nolloth Museum was able to sequence a number of the genes from an old specimen. It was a match. The EWT team now believe that there is a ‘healthy’ population of De Winton’s golden moles on the coast of Port Nolloth. They are seeking to have the location declared a protected area.

“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.”

Do you want to keep up to date? If so, browse our other articles here.