Biologists compete over North America’s largest crayfish

by Lauren Quinn, University of Illinois – Urbana-Champaign
September 23, 2026

When Caitlin Bloomer wrestled the massive Crawzilla crawdad — yes, that’s its actual common name — out of the muck during a bio-survey event in Kentucky, she was convinced it was the largest crayfish ever recorded. 

“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 fisherman do, he took one look and said, ‘No way, I’ve caught bigger,’” said Bloomer, teaching assistant professor in the Department of Natural Resources and Environmental Sciences, part of the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois Urbana-Champaign.

The friendly competition between colleagues quickly accelerated. Bloomer enlisted biologists and museum curators around the country to inventory their collections for the largest specimens. Armed with precise measuring tools called calipers, the crayfish crew identified 20 individuals across 18 species that trended larger than all the rest. They published the rankings in Ecology.

Keep reading: https://aces.illinois.edu/news/biologists-compete-over-north-americas-largest-crayfish

Read the Ecology paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.70471