There's a quiet detective hiding inside a hedgehog's little pile of droppings — and it could hold the key to saving one of Britain's most loved but troubled creatures.
Emily Harper, a Ph.D. researcher, has spent her time learning how to read stress from hedgehog poop. Her new study, published in the journal Conservation Physiology, confirms a gentle way to measure stress in European hedgehogs without ever laying a glove on them. By studying hormones in their feces, scientists can now see which threats really worry these spiky animals.
Why does stress matter so much? Stress is a healthy, natural response to danger — it's what lets an animal bolt or fight in a tight spot. But when threats drag on, that short burst turns into chronic stress. It weakens immunity, harms reproduction, and raises death rates. For the European hedgehog, already in decline, knowing what stresses them out could offer vital clues about the challenges they face.
Hedgehogs are what scientists call an "indicator species" — like a canary in a coal mine, they reflect the overall health of their environment. They're also Britain's most rescued mammal, with around 40,000 hedgehogs in captivity in the U.K. at any given time.
The method works by tracking a group of hormones called glucocorticoids. When a hedgehog feels threatened, a chain reaction in its body — the fight-or-flight system — pumps out these helper hormones, which eventually leave the body in pee and poop. High, lingering levels signal chronic stress. To make sure the test actually works, the research team tested three different chemical assays on hedgehogs admitted to rehabilitation centers.
The results were revealing. Fecal glucocorticoid levels peaked the day after admission — no surprise, since admission means capture, transport, exams, and veterinary treatment, all stressful events. Right on schedule, those levels dropped back down seven days later.
But the most striking finding: hedgehogs admitted to rehabilitation that later died had significantly higher stress hormones in their poop than those that survived. So did hedgehogs infected with a tiny gut parasite called Capillaria. After a week of care, though, stress levels in recovering hedgehogs returned to the same healthy range as wild, uninfected hedgehogs — proof that good rehabilitation works.
Now that the test is validated, researchers can use it to measure how hedgehogs cope with habitat loss, food shortages, and human activity, and to check how released animals adapt once they return to the wild. It's a simple, kind tool that lets us listen to what these animals can't say in words — and act on what they tell us.