Collisions with robotic lawnmowers during the night pose a serious threat to hedgehogs, often resulting in severe injuries or mortality. To address this issue and enhance the safety of robotic lawnmowers for hedgehogs, researchers from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), the crash test company CTS, and the computer magazine c’t are creating specialized hedgehog dummies along with standard testing procedures to prevent deadly encounters. Experts from various fields will gather to discuss the latest advancements in this initiative, along with other critical topics on hedgehog research, animal welfare, and conservation at two conferences hosted by the Leibniz-IZW in Berlin from January 16 to 19, 2025.
In October 2024, the teams from Leibniz-IZW, CTS, and c’t conducted tests on hedgehog dummy prototypes to gauge how closely they mimic real hedgehogs. These dummies do not need to visually resemble actual hedgehogs; rather, they must replicate their behavior under the approach and impact of a robotic mower, allowing for legitimate and consistent safety evaluations. Throughout the testing process, the group compared a CTS-developed prototype with genuine, previously deceased hedgehogs from the Leibniz-IZW. The dummies feature a 3D-printed internal frame, can be warmed to match a hedgehog’s body temperature, and are available in various sizes and postures (curled and uncurled). They are designed to closely match the appearance, weight-to-size ratio, and flexibility of real hedgehogs. This will enable future testing across all robotic mower models, irrespective of their object detection technologies (like laser, ultrasound, optical, thermal imaging, or bumper contacts), to evaluate how effectively these models can identify hedgehogs. Accurate construction, appropriate weight, and stability are critical, especially for mechanical detection through impact sensors. Besides evaluating hedgehog detection, the project also analyses injuries sustained by both hedgehog carcasses and the dummies during identical (forced) encounters with robotic mowers.
“Our tests demonstrated a high degree of similarity between injuries found on the hedgehog carcasses and those on the dummies during the forced collisions,” remarks hedgehog expert Dr. Anne Berger from the Leibniz-IZW. “Nonetheless, the dummies are still slightly heavier and less flexible than actual hedgehogs, and we plan to make further enhancements in the upcoming months. The team will conduct final testing in spring 2025 to finalize the dummies.” Berger, along with her colleagues at CTS and c’t, is striving to establish an SI-DIN standard in Germany, which would mandate standardized crash testing of robotic lawnmowers utilizing these dummies for all brands and models on the market. Such tests will reveal how well each robotic mower can detect hedgehogs and implement evasive actions or emergency stopping.
Previously, Berger and her team executed extensive studies examining hedgehog injuries caused by robotic lawnmowers. This included analyzing 370 reported cases of hedgehog injuries across Germany, finding that the injuries were consistently distributed throughout the week. “This strongly indicates that robotic lawnmowers primarily cause these injuries, as they are the only devices legally permitted to operate on Sundays,” Berger notes. Alarmingly, nearly half of the hedgehogs (47%) reported found did not survive their injuries. Hedgehog rescue organizations are witnessing a consistent rise in cases of injured hedgehogs, highlighting an escalating conservation issue amid decreasing hedge populations in Germany. “We also suspect that a significant number of injured or deceased hedgehogs go unnoticed or unreported,” Berger adds.
Since hedgehogs can endure injuries for extended periods, and such animal suffering is outlawed if alternatives exist that don’t cause the same level of pain, scientists like Berger are collaborating with national and international partners to develop these alternatives. One area of focus includes robotic mowers, which must demonstrate through standardized tests their capability to accurately detect and avoid hedgehogs.
Moreover, there are other effective and even quicker strategies to enhance hedgehog protection, according to Berger. For instance, banning the use of robotic lawnmowers at night, as some local authorities in Germany have already done, could drastically lower the risk to hedgehogs. Operating unsupervised at night is particularly hazardous, as hedgehogs are nocturnal and tend to stay still and quiet when confronted with danger. If injured by the mowers, hedgehogs might silently seek refuge in bushes and hedges to avoid drawing attention from predators. Unfortunately, even minor injuries can lead to severe infections or become breeding grounds for fly eggs, which can be fatal if untreated.
From January 16th to 19th, 2025, hedgehog specialists from both national and international backgrounds will convene for two conferences organized by the Leibniz-IZW in Berlin. The “10th Meeting of the European Hedgehog Research Group” on January 16 and 17 will delve into new research perspectives regarding hedgehogs, touching on genetics, diseases, parasites, and conservation challenges such as population dynamics. Following this, the “2nd Exchange and Training Event for Hedgehog and Wildlife Care Stations” on January 18 and 19 will focus on practical issues faced in caring for hedgehogs and other wildlife while providing scientific insights. This event will also foster networking among various hedgehog and wildlife rescue centers in German-speaking countries, thereby amplifying the impact of individual centers’ conservation efforts.
The latest results from the dummy crash tests conducted by Leibniz-IZW, CTS, and c’t will be shared and discussed during these conferences. DIN-certified safety testing may also be addressed in future sessions of the hedgehog community across Germany and Europe.
