If a robotic lawnmower approaches a hedgehog, it does what it does with other enemies: rolls up into a ball of spikes.

They're rolling again in many gardens: robotic lawnmowers designed to keep the lawn short without any effort on their part. They pose a deadly threat, especially to hedgehogs. The nocturnal animals don't run away, but curl up, explains Julia Stubenbord, State Animal Welfare Officer in Baden-Württemberg. As a result, the number of injured hedgehogs has increased significantly with the increase in robotic lawnmowers.

Experts from the German Federation for the Environment and Nature Conservation (BUND) and the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) have long been calling for a nighttime driving ban for robotic lawnmowers. Some municipalities, such as Cologne, Mainz, and soon Erfurt, have already implemented this.

Last year, the institute published figures together with hedgehog rescue centers: From June 2022 to October 2023 alone, 370 hedgehogs with cut injuries were reported nationwide. Almost half (47 percent) did not survive. In addition, there is a high number of undetected injured or killed animals, as run-over hedgehogs flee to the protection of hedges and bushes—if they still can.

At least 60 percent of the hedgehogs with cut injuries were only found days or even weeks after the accident, explained Anne Berger of the Leibniz-IZW. This means they had to suffer significantly over a long period of time. "Such animal suffering is prohibited by law as long as there are alternatives that do not cause animal suffering."

Hedgehog numbers are dwindling – and not just because of robots. According to the German Wildlife Foundation, the animals lack suitable habitat in modern agricultural landscapes and in tidy, over-manicured gardens. Many hedgehogs are run over or find too little food due to the rapid decline in insect populations.

In Germany, the European hedgehog (Erinaceus europaeus) is on the early warning list of the Red List, and on the international Red List of the International Union for Conservation of Nature (IUCN) it is classified as “near threatened”.

The manufacturer Stihl says the company is aware that robotic lawnmowers pose a risk of injury to hedgehogs. "We have done a lot to reduce this risk in the development of the current generation of our robotic lawnmowers," a spokeswoman said.

To protect crepuscular and nocturnal animals, night-time activation is not included in the preset mowing schedules. If night-time activation is explicitly requested by the user and programmed in the robotic lawnmower app, the user receives a warning that this should be avoided to protect small animals.

BUND advises questioning whether a robotic lawnmower is even necessary: ​​Leaving it out is not only beneficial for hedgehogs, but also for insects, amphibians, and other animals. Allowing the lawn to grow taller and bloom is a real benefit for biodiversity.