A recently published study conducted by Dr Sophie Lund Rasmussen, known as 'Dr Hedgehog', along with colleagues from Oxford University and Aalborg University has found that different models of robotic mowers vary substantially in their capability to detect and avoid hurting hedgehogs.

Dr Rasmussen's research involved testing 18 models of robotic mowers in collision tests with dead hedgehogs. The dead hedgehogs in the study were collected from hedgehog rehabilitation centres, where they had been too injured or unwell to save. Each robotic mower was tested 12 times; with four dead hedgehogs representing four different weight classes, each tested in three different positions.

The results from the study, which can be read in full here, showed that some models caused extensive damage to the dead hedgehogs in the tests, but there were noteworthy differences in the degree of harm inflicted, with some machines consistently causing no damage.

“The important next step is to present the results and insights from the research to the manufacturers and encourage a collaboration with them to develop more hedgehog and wildlife friendly robotic lawnmowers,” says Dr Rasmussen, who has already started these discussions.

In order to limit the potential for harm to hedgehogs from robotic mowers, the present recommendation is to restrict the running of the machines to daylight hours - however garden owners are advised to check in advance for any hedgehogs, or other potentially vulnerable wildlife such as leverets, amphibians or baby birds on the lawn.

The research project was undertaken in collaboration with Animal Protection Denmark and Pindsvine Plejerne and was funded by the British Hedgehog Preservation Society.