Do Robot Mowers Kill Hedgehogs? What the Research Shows

What did the research actually find?

The strongest evidence is a 2021 paper in the journal Animals by Sophie Lund Rasmussen and colleagues. They tested 18 robot mower models against dead European hedgehogs, placed in positions based on how live hedgehogs behave. Each model was tested 12 times.

• Some models caused extensive damage to the carcasses. Others consistently caused none. The injuries seen ranged from puncture wounds to far worse.
• Every model had to touch a hedgehog to detect it. None was able to detect a dependent juvenile under 200 g.
• Three design features significantly improved the safety score: pivoting blades, skid plates and front-wheel drive.

There is an important caveat. The study used dead hedgehogs, so it shows what a mower's blades can do on contact, not how often a live hedgehog ends up in the way. The authors say plainly that they could not assess how likely encounters are.

A later study looked at the live side. Researchers exposed 50 rehabilitated hedgehogs to a mower with its blades removed (100 encounters, no animal could be cut). Only 15% ran away, 43% held still in the posture they were placed in, and only one of 100 tests ended with the hedgehog curling into a ball. Most did not run.

The picture before this research was murkier. The Danish researcher behind the work had examined 697 dead hedgehogs from across Denmark and none showed signs of being killed by a robot mower, with some wounds consistent with strimmers or dog bites. The tests came afterwards to find out whether the models themselves were dangerous.

Why are hedgehogs so vulnerable?

Hedgehogs are small, low to the ground and mostly active at night, which is when many people schedule their mowers. A mower that only reacts to a bump has already touched the animal by the time it reacts. The 2021 results suggest that is the case for the models tested. A hedgehog under 200 g, a young one, is the hardest case.

How do I lower the risk?

None of these is a guarantee, but they are the steps the researchers recommend or that follow from the findings.

1. Mow in daylight only. The 2021 paper says restricting mowers to daytime might largely obviate the problem, and says sellers should tell customers not to run them at night. Hedgehogs can still be out in daylight, so this lowers the risk without removing it.
2. Check the lawn before it runs. The authors advise checking for hedgehogs and other wildlife, such as leverets and fledglings, before mowing.
3. Clear the hiding places. Leaf piles, long grass at the fence line and the base of hedges are where a hedgehog may rest. Fence them off in the app as no-go zones.
4. Check the app's schedule controls. You want to set exact start and stop times per day, and per area, so the mower never runs at dusk or dawn by default.
5. Ask about blade design. Pivoting blades were the strongest design factor in the study. Our spec database does not record blade design, so ask the manufacturer before you buy.

Is a mower with AI obstacle detection safe for hedgehogs?

We found no independent test showing it is. Newer mowers use cameras, LiDAR and radar rather than only a bump sensor, and some makers say so loudly. ECOVACS, for example, says its GOAT O1000 LiDAR PRO can avoid more than 200 types of obstacles, "including hedgehogs". That is a manufacturer claim. We found no independent test of it, and the 2021 study did not include current models. A curled-up hedgehog on dark grass is also a hard target for a camera. Treat the sensors as a second line of defence behind a daylight schedule, not a replacement.

What would we buy?

If you have hedgehogs in the garden, the honest answer is that no mower is proven safe, and the safest option is a hand-controlled one or a mower you only run supervised, in the daytime. If you want a robot mower anyway, the things to buy for are per-area scheduling you can lock to daylight, map control for no-go zones, and obstacle sensing that goes beyond a bump sensor. From the models in our database:

• Ecovacs GOAT O1000 LiDAR PRO has the most direct claim, with AI vision plus LiDAR obstacle avoidance and per-area schedules. Its trimmer is louder than the mower body, which matters if you run it at dusk next to a hedge.
• Husqvarna Automower 410 iQ uses radar-based object detection, with a weather timer and work areas you can restrict. It has no camera, so it is a different approach rather than a proven safer one.
• Dreame A3 AWD 1000 combines LiDAR with AI vision and per-zone management in a compact body.

Whichever you choose, set the schedule first and check the result after a week. The finder filters by lawn size and navigation if you want to narrow it down. If you are not yet sure a robot is worth it for your lawn at all, see are robot mowers worth it.