A giant crayfish nicknamed "Crawzilla" has sparked an unexpected scientific discovery, revealing a possible biological limit to how large North America's crayfish can grow. The investigation began when Caitlin Bloomer pulled an enormous Crawzilla crawdad from the mud during a biological survey in Kentucky. Crawzilla is the creature's actual common name, and Bloomer was convinced she had captured the largest crayfish ever documented.
But when she proudly showed her discovery to a colleague, the reaction was not quite what she expected. "I thought, 'There's no doubt I have caught the biggest crayfish anyone's ever seen!' I brought it back to campus to show my colleague, naturally bragging about having caught the biggest-ever crayfish. But, as all biologists and sport fishermen do, he took one look and said, 'No way, I've caught bigger,'" said Bloomer, a teaching assistant professor in the Department of Natural Resources and Environmental Sciences within the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois Urbana-Champaign.
A Nationwide Hunt for North America's Biggest Crayfish What started as a little friendly rivalry soon turned into a nationwide search for record-breaking crayfish. Bloomer contacted biologists and museum curators across the country, asking them to examine their collections for unusually large specimens. Using calipers, instruments designed to measure objects with great precision, the researchers compared the sizes of preserved crayfish.
Their search produced a list of 20 exceptionally large individuals representing 18 different species. The results were published in the scientific journal Ecology. Although Bloomer's original Crawzilla did not claim the top spot, it still earned a place among the largest specimens identified.
"Mine was not the biggest, but it did make the top 20, so I'm super proud of it," Bloomer said. "And it was also the only burrowing crayfish to make the list, so I'll take the win." Scientists Identify the Largest Known North American Crayfish The biggest specimen belonged to a Tennessee bottlebrush crayfish preserved in the collection at West Liberty University in West Virginia. It measured an impressive 86.6 millimeters, or approximately 3.4 inches, excluding its tail, claws, and antennae.
The record-holder was not a recent catch. It had been collected in 2011 by Dr. Zac Loughman and students from West Liberty University, making the discovery possible through the examination of existing museum specimens.
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