In the city of Prague, two closely related hedgehog species share the same streets, parks and gardens, yet a seven-year record of thousands of rescued animals shows they lead strikingly different urban lives. Researchers at the Czech University of Life Sciences Prague analyzed 4,253 cases involving the Western European hedgehog (Erinaceus europaeus) and the Northern white-breasted hedgehog (Erinaceus roumanicus) admitted to the Prague Wildlife Rehabilitation Centre between 2017 and 2023.
The two species meet across a broad swath of Central Europe, and Czechia hosts the widest area of overlap in their distributions. Although hybridization between them is very rare, both species show high variability in physical traits, making identification in the field challenging. At the Prague rehabilitation center, however, species recognition had been previously validated, offering researchers a rare opportunity to compare the two animals within a single urban environment using reliable records.
Most of the admitted hedgehogs, 3,692 cases or 86.8 percent, came from within Prague itself, while 513 cases arrived from the surrounding Central Bohemian region and 48 from unspecified locations outside the city. Each record contained the species identification, sex, age estimate, location and date of admission, reason for admission, and the animal’s eventual fate. Because the animals were not marked, the same individual could theoretically appear multiple times in the dataset, and sex was known in only 14 percent of cases, so it was excluded from analysis. Hedgehogs were grouped into two age categories: young, meaning before their first hibernation, and adult, after it.
When the researchers mapped the cases with known geographic coordinates across the city, a clear spatial divide emerged. The Northern white-breasted hedgehog dominated the eastern portion of Prague, with 76.6 percent of its cases found on the eastern bank of the Vltava River, while the Western European hedgehog concentrated in the southwest, with 64.8 percent of its cases on the western bank. The river bisects the city from south to north and in many places exceeds 100 meters in width, a span that may be difficult for hedgehogs to cross. Although 20 bridges span the river, only three are pedestrian-only, which could reduce their accessibility to the animals. The pattern suggests the Vltava may act as a dispersal barrier, consistent with earlier studies that identified large rivers as obstacles to the movement of small mammals, including hedgehogs.
The seasonal timing of admissions also differed sharply between the species. Young animals made up the majority of admissions in both, at 71.6 percent for the Northern white-breasted hedgehog and 67.6 percent for the Western European hedgehog. But the Western European species showed a single peak in young admissions in September and October, consistent with one litter per year, while the Northern white-breasted species displayed two peaks, one in June and July and another in September and October, a pattern consistent with two litters annually. Adults of both species were most commonly admitted in May, though adult Western European hedgehogs rose again in September and October in some years while adult Northern white-breasted hedgehogs generally declined in fall.
These reproductive differences align with earlier literature suggesting the Northern white-breasted hedgehog awakens from hibernation earlier than its Western European relative. The timing and duration of hibernation are strongly shaped by climate through their effect on seasonal food availability. In milder southern European regions and areas with oceanic climates, hibernation tends to be shorter and the breeding season extended, whereas in northern and more continental regions, prolonged winter resource scarcity usually restricts reproductive activity to a single litter per year. The researchers suggest this asynchronous breeding may represent a temporal niche segregation mechanism that reduces competition for food and minimizes the risk of hybridization, though they caution that these inferences rest on admission patterns rather than direct field observations.
Rehabilitation outcomes also diverged. Across the full dataset with known outcomes, release was the most common result at 56.0 percent, followed by unassisted death at 37.5 percent and euthanasia at 6.5 percent. When outcomes were treated as a simple binary of release versus death, the Northern white-breasted hedgehog achieved a higher release rate of 60.5 percent compared with 47.9 percent for the Western European hedgehog. The gap appeared across all seasons, with the Northern species outperforming by roughly 10 percentage points in spring, summer and fall, and by approximately 30 points in winter.
To account for the influence of season and reason for admission, the researchers built a generalized linear model with a binomial error distribution. The model predicted an overall release probability of 46.6 percent for the Northern white-breasted hedgehog versus 44.1 percent for the Western European hedgehog, a difference that was not statistically significant overall. However, the model did detect significant interspecific contrasts in specific contexts: in winter admissions, where the Northern species had a roughly 20 percent higher predicted release probability; in cases of exhaustion and starvation; and in hoglets, the term for young hedgehogs. The most striking observed difference appeared in infections and parasites, where the Western European hedgehog’s release rate of 28.2 percent more than doubled the Northern species’ 12.0 percent.
Annual release rates told another story of divergence over time. The Northern white-breasted hedgehog’s rates remained stable at approximately 60 percent throughout the study period, ranging only from 53.3 to 65.2 percent. The Western European hedgehog, by contrast, started at 65.4 percent in 2017 and declined steadily to 31.7 percent by 2023. The researchers note that shifts in the composition of admitted cases alone are unlikely to explain this trend, as the relative frequency of admission reasons stayed broadly similar across the seven years, with hoglets consistently the most frequent category. Other factors, such as management changes at the center, public awareness, or the disruption caused by the COVID-19 pandemic, may have played a role, though the authors consider it unlikely these would affect the two species disproportionately.
The study demonstrates that wildlife rehabilitation center records, despite being an opportunistic and non-random subset of the population, can serve as a valuable source of comparative ecological information. The authors emphasize that release outcomes may reflect not only species-specific ecology but also the composition and severity of admitted cases, and that direct extrapolation to population-level processes should be made with caution.
Subject of Research: Comparative urban ecology of two sympatric hedgehog species in Prague using wildlife rehabilitation records
Article Title: Contrasting urban ecology of two hedgehog species in Central European contact zone
Article References: Cetkovská, E., KlÃmová, A., Pokorná, Z., & ÄŒerná BolfÃková, B. (2026). Contrasting urban ecology of two hedgehog species in Central European contact zone. BMC Zoology, 11(1), Article 33. https://doi.org/10.1186/s40850-026-00279-x
Image Credits: AI Generated
DOI: 10.1186/s40850-026-00279-x
Keywords: hedgehogs, Erinaceus europaeus, Erinaceus roumanicus, Prague, urban ecology, wildlife rehabilitation, Vltava River, contact zone, reproductive timing, release rates, Central Europe, species distribution
News Source: Drew Townsend. (November 5, 2026). Two hedgehog species split Prague along a river line, seven-year records reveal. Scienmag.
