Experts Baffled to Find 8,000 Ancient Frog and Toad Bones Near an Iron Age Site. 'This Is a Puzzling and Unexpected Find'

Scientists were shocked when they came face-to-face with several ancient frog and toad bones in the U.K. around eight years ago. The remains were spotted near the site of an Iron Age roundhouse at Bar Hill, stated BBC. In total experts found remnants of 350 amphibians. Scientists were taken aback because it was rare to find so many amphibian fossils in the same place.

Most of the remains were spotted in a 14-meter-long (46ft) ditch placed on the west of a roundhouse on the site. As per analysis, the roundhouse was functioning in the Middle and Late Iron Age (400BC - AD43). Experts were confused as to why so many amphibian remains were deposited at this particular location. The team found evidence of only a few other amphibian bones in the nearby archaeological sites.

Researchers claimed that though finding amphibian bones was not unusual, the number of them makes the finding extraordinary. There were 8,000 amphibian bones on the site, stated The Guardian. "In my experience, mainly working on sites from London, we don’t get that many frogs. To have so many bones coming from one ditch is extraordinary," Dr. Vicki Ewens, senior archaeozoologist at the Museum of London Archaeology (Mola) said. Researchers were ecstatic with the discovery of pool frog bones. "We’ve also had possible evidence of pool frog, which is exciting… It’s not something that we usually find archaeologically," Ewens added. "In my research, I’ve only found two Saxon sites with single bones on each. They’re a frog that was only found in East Anglia that died out in the 1990s, possibly due to habitat loss, but has recently been reintroduced.”

Researchers analyzed the bones and found that there were no burns, bites, or cut marks, stated BBC. This implied that they were not eaten by a hunting animal who collected their bones on the spot. Experts have come up with various speculations regarding the presence of these bones. They believe that the amphibians possibly got drawn to the spot, in pursuit of food. This theory was backed by evidence of food processing in some places of the site. These methods invite beetles and aphids, which are in turn eaten by frogs. 

Another possible reason could be that these frogs fell into the ditch while migrating to search for breeding grounds. They may not have been able to get out and breathed their last at the place. The researchers claim that winter hardships faced by prehistoric amphibians could have also been the cause behind the mass deaths. The bones were unearthed between 2016 and 2018, amidst excavations alongside a new route. Analysis of remains was still ongoing in 2022  "This is a puzzling and unexpected find, which we are still trying to fully understand," Dr. Ewens stated. "This accumulation of frog remains may have been caused by a number of different factors, possibly interacting over a long period of time - we just aren't sure yet what these were." Examinations till then showcased that the amphibian bones were prehistoric.