Eurasian Otter (Lutra lutra)
The Eurasian otter (Lutra lutra) is the only otter species native to the UK. They’re now present throughout the UK, having returned to many watercourses since their decline in the 1950s to 1960s. Restrictions in the UK on certain chemical pesticides and fertilisers, as well as conservation efforts have allowed for their slow recovery.
Genetic Identification of Otter from Spraints
DNA testing is particularly useful for rare, elusive or secretive wild animals such as the Eurasian otter; a largely nocturnal, secretive and semi-aquatic species. Therefore, genetic analysis of non-invasive samples (e.g. faeces) present themselves as a feasible method for obtaining genetic and population data.
Otters deposit faeces, known as spraints, on features near to water including fallen trees, logs, rocks and storm drains. Spraints are used to define and defend territories and to communicate with other otters.
Spraints are about 2-7cm long and largely contain fish bones, scales and shells. It is tarry and black and turns grey when it’s old. Having smelt spraint myself, I can confirm that it smells like jasmine tea!
Sometimes it can be difficult to distinguish between faeces of otters and other mustelid species such as minks (Mustela vison) as the stature is similar and their diets largely overlap.
We are working with local otter enthusiasts to help track, monitor and conserve County Durham’s Eurasian otter population.
We are using DNA testing technology to analyse spraints collected from the areas pinpointed on the map. We will extract DNA from the spraints for species identification, gender determination and relationship testing.
The main advantage of using DNA-based approaches is the potential to identify specimens to species level through analysis of DNA extracted from faecal samples. For otters, DNA typing of spraints can be used to provide estimates of dispersal, genetic diversity, home ranges, population size and territories for monitoring purposes.