Researchers have long been aware that the techniques they use had the potential to cause unexpected effects, and there have been many studies into the effects of radio-collars. However, this is the first study to show an association between radio-collars and sex ratio, although further work is needed to establish a causal link. According to Moorhouse and Macdonald: "We would expect any such effect to be species-specific, but our results will alert those studying other small mammals to look for similar associations. Our findings are a reminder that the assumption that the use of radio-collars does not fundamentally affect the biology of the subjects always requires careful checking. This study emphasises that the effects of commonplace wildlife marking and tracking techniques may be difficult to detect and yet both important and revealing. Clearly, it is both scientifically and ethically important to be aware of, and to strive to minimise, any such effects."