RomeRoman Britain · Bar Hill, Cambridgeshire, United Kingdom
Owls ate the 8,000 frogs found in a Roman ditch in Cambridgeshire, study finds
Damage on the bones points to short-eared owls or hen harriers, and most of the frogs were caught in the winter of their first year.
In brief 3 key points
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- 8,000 frog bones were found in one ditch during A14 roadworks between 2016 and 2018
- Damage on the bones matches birds of prey, most likely short-eared owls or hen harriers
- Radiocarbon dating places the frogs about 1,700 years ago, in the Roman period
Ten years after 8,000 frog bones turned up in a single ditch in Cambridgeshire, researchers have named the likely culprits. The frogs were eaten by birds of prey, most likely short-eared owls or hen harriers.
Paul Clarkson of Bournemouth University led the study with Vicki Ewens, senior zooarchaeologist at the Museum of London Archaeology (MOLA). It appears in the journal Environmental Archaeology.
A ditch full of bones
The bones came to light on the A14 Cambridge to Huntingdon road scheme between 2016 and 2018, at a site near Bar Hill. Clarkson saw the find in the news and contacted Ewens to study it further.
He compared the damage on the bones with earlier studies and found the marks of birds of prey. Evidence on site showed that the ditch filled within a single year. That left the question of how so many frogs died in so short a time.
Young frogs in winter
The team measured the frogs' humeri, the upper arm bones, a new method of analysis. Most frogs died young, eaten in the winter of their first year. Radiocarbon dating by the University of Vienna placed the bones about 1,700 years ago, in the Roman period.
The waters of the Fens were retreating from the valley at the time, which made good breeding ground for frogs. Snail, pollen and charcoal evidence shows that woodland was felled over time for grazing. By the Roman period, open ground left the frogs exposed to hunters of grassland.
“We don't often get an owl's eye view of what it was like in the past from archaeological sites.”
Paul Clarkson, Bournemouth University
The researchers suggest the birds were helped by a quiet landscape. Communities may have visited the area seasonally to move livestock to new pasture.
Sources (2)
Peer-reviewed paperfrom Bournemouth University, Museum of London Archaeology and University of Vienna
- Cracking the case of the Roman frog graveyard (Phys.org)
- Scientists identify what killed 8,000 ancient frogs found in a single ditch in Cambridgeshire (EurekAlert! (Bournemouth University))
Paper: Clarkson et al., An Owl's Eye View: Human–Animal Entanglement at the Roman Fen Edge, Environmental Archaeology (2026)
Edited by Guiseppe Weijermars
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