EuroSpeleo 2016 Sessions

World’s First Geophysical Surveys of Bat Guano

Session code: OS14

Oral / Science, Main EuroSpeleo Conference

Dr George Veni


Bracken Cave, Texas, USA, holds the world’s largest colony of bats, estimated at 40 million. But what is the depth of the bat guano that covers the floor? Working with Bat Conservation International and other partners, the US National Cave and Karst Research Institute conducted the world’s first geophysical surveys of bat guano. Using electrical resistivity methods and overcoming various technical challenges, the guano is estimated at about 35 m deep. Analyses of the results plus limited coring to date for paleoclimatic and paleoenvironmental research has verified some of the findings and found limitations to the method. Additional resistivity surveys will be run next year to refine the results, and reconfigured to see greater depths through the breakdown below the guano, and its underlying sediment, to map the underlying bedrock cave floor.


Caver for over 40 years. Karst hydrogeologist for nearly as long.
Executive Director of the US National Cave and Karst Research Institute
Vice President of Administration of the International Union of Speleology