Snail Shells Record Extreme Rainfall and Could Map Prehistoric Cyclones, Study Finds

A new University of Queensland-led study has found that the growth bands of a Biggenden Banded Snail shell can record extreme rainfall events, opening a possible path to reconstructing the tracks of past and prehistoric tropical cyclones. The research, published in the journal The Holocene, examined a single snail collected from Coalstoun Lakes National Park in southeast Queensland and linked its growth spurts to severe weather rather than ordinary seasonal wetness.

Palaeoclimate scientists have long sought natural archives that can extend weather records beyond the instrumental era. Tree rings, ice cores, corals and lake sediments have all served as proxies for past climate conditions, but direct evidence of individual cyclone events has remained difficult to obtain, especially for periods before modern meteorological observations began. The new study suggests that land snail shells, which are abundant in many terrestrial environments, could help fill that gap.

The snail in question belongs to the species Figuladra bayensis, commonly known as the Biggenden Banded Snail. It was collected from Coalstoun Lakes National Park, a 26-hectare protected area about 230 km northwest of Brisbane. The park sits on volcanic lakes formed roughly 600,000 years ago. According to Xinhua, the researchers chose the site partly because it has a unique microclimate, can be examined in detail by satellite, and is home to a large native snail.

The project was led by Dr Nicholas Patton of the University of Queensland School of the Environment, with Honorary Professor Jamie Shulmeister also from UQ. Collaborators included Dr Quan Hua from the Australian Nuclear Science and Technology Organisation (ANSTO) and Professor Melanie Leng of the British Geological Survey and the University of Nottingham. The study was published in 2026 in The Holocene.

Key Facts

Xinhua reported on September 14, 2026, that researchers examined the rings on the shell of a Biggenden Banded Snail collected from Coalstoun Lakes National Park in Australia's southeast Queensland. Tiny samples taken from the shell at millimetre intervals were analysed using high-resolution radiocarbon dating. Dr Nicholas Patton, the lead author, said the shell contained elevated levels of radiocarbon from nuclear tests in Australia in the 1960s. 'It contained elevated levels of radiocarbon from the nuclear tests in Australia in the 1960s, meaning we could date the growth bands and reveal the snail had lived for about 4.5 years,' Patton said. The snail is believed to have died in mid-August 2018.

Phys.org reported on September 14, 2026, that analysing the oxygen and carbon stable isotopes of the different bands revealed insights into the rainfall the snail experienced. Dr Patton said the shell did not grow continuously; there were periods of rapid growth separated by periods of little or no growth. The team initially expected the rapid growth phases to correspond to years with heavier rainfall, which would have made more food available for the snail. However, Honorary Professor Jamie Shulmeister said the results showed the snail was responding to extreme rainfall events rather than annual wetness.

Because the researchers knew when the snail lived, the growth spurts could be linked to periods immediately following cyclones in 2015 and 2017. Severe Tropical Cyclone Marcia and Tropical Cyclone Debbie both caused extreme rainfall within Coalstoun Lakes National Park. Shulmeister said: 'It shows that snail shells could be used to map extreme weather events for periods before modern meteorological records.' He also said it was surprising and quite exciting that the humble snail could be a tool to reconstruct the paths of past cyclones even in prehistoric times.

Yahoo News Australia reported on September 14, 2026, that the team selected the 26-hectare Coalstoun Lakes National Park, 230 km northwest of Brisbane, as its study area for three key reasons: a unique microclimate, the ability to examine it in detail by satellite, and the presence of a large native snail. The park sits on volcanic lakes formed roughly 600,000 years ago. Shulmeister explained that the volcanic lakes were not connected to the rest of the country outside and that these closed areas were the perfect study site. The National Tribune reported on September 14, 2026, that the research was completed with Professor Melanie Leng of the British Geological Survey and University of Nottingham, and Dr Quan Hua from ANSTO.

Analysis

The study adds a new, unexpected proxy to the palaeoclimate toolkit. Snail shells are common in many terrestrial deposits, and if their growth bands reliably record extreme rainfall, they could provide a window into storm activity that predates instruments. What this really means is that scientists may be able to reconstruct the paths of past cyclones by analysing shells from different locations and times, potentially extending the record of tropical cyclones back thousands of years. That is a significant shift because direct evidence of individual prehistoric storms has been extremely scarce.

The finding also challenges a simple assumption about how land snails grow. The team expected growth to track annual rainfall, but the data pointed to a response to extreme events. That distinction matters for interpretation. If growth spurts are triggered by the immediate aftermath of cyclones, then a shell is not a general rain gauge but a recorder of intense, discrete disturbances. This makes the proxy potentially more specific for cyclone reconstruction, even as it complicates efforts to read average conditions from the same bands.

However, the study is based on a single snail shell. The researchers acknowledge that they used the shell of one deceased snail, though they expect to find a similar connection between growth and rain in almost any land snail species. That expectation is plausible given the physiological link between moisture and snail activity, but it remains to be tested across species and environments. The involvement of ANSTO's radiocarbon expertise and the British Geological Survey's stable isotope laboratory adds credibility to the analytical work, but broader validation will be needed before the method becomes a standard tool.

The bigger picture here is that palaeoclimatology often relies on proxies that are indirect and require careful calibration. Snail shells could complement existing archives such as tree rings and lake sediments, especially in regions where those archives are absent. Yet the method will need many more shells and sites to move from a promising case study to a robust technique. The study's publication in The Holocene signals that the work is being taken seriously by the palaeoclimate community, but it is a first step rather than a final answer.

Why It Matters

Improved understanding of past cyclone activity matters for risk assessment and for testing climate models. Modern meteorological records cover only a few decades in many regions, and satellite monitoring is even shorter. If snail shells can reliably record extreme rainfall, they could help fill gaps in the historical and prehistoric record, offering clues about how often and where cyclones made landfall in the deep past. That could inform debates about long-term patterns in tropical cyclone frequency and intensity.

The research also highlights the value of interdisciplinary collaboration. The project brought together the University of Queensland's School of the Environment, ANSTO's radiocarbon dating capabilities, and stable isotope expertise from the British Geological Survey and the University of Nottingham. Such combinations allow scientists to extract multiple lines of evidence from a single sample. In this case, radiocarbon dating provided a timeline, while oxygen and carbon isotopes provided information about rainfall. The result is a detailed life history of one snail that can be compared with weather observations.

Finally, the study underscores how much can be learned from common organisms. The Biggenden Banded Snail is a large native species in a small national park, yet its shell has yielded insights that could have global implications. As Shulmeister suggested, the humble snail could become a tool for reconstructing the paths of past cyclones, including those in prehistoric times. That is a compelling example of how curiosity-driven research can produce practical proxies for understanding extreme weather.

Next Up

The team expects that older or even fossilised shells could be used to reconstruct past extreme weather events. Future work will likely focus on testing the method across more snail species and more locations, and on refining the link between growth bands and specific rainfall events. The researchers may also try to identify shells that lived during periods with known cyclone activity to see whether the proxy holds up outside the Coalstoun Lakes case.

For now, the study offers a proof of concept. The next steps will involve building a larger dataset of dated shells and comparing them with independent climate records. If that effort succeeds, snail shells could join the small set of natural archives that allow scientists to peer into the stormy past, well before humans began keeping written weather records.