Freediver David Vencl not only broke the human record for the longest swim under ice this week, he made it farther than any polar bear on record. The Czech swimmer wore only swim trunks and goggles Tuesday when he swam underneath ice for almost 266 feet in a disused quarry northeast of Prague, CBS reports. Reuters reports that the 38-year-old said "This will do" after emerging from water whose temperature measured 37 degrees Fahrenheit. The previous record of 250 feet was set by Denmark's Stig Avall Severinsen in 2017. In a 2015 study in Polar Biology, researcher Ian Stirling said a 165-foot swim under the ice over 3 minutes and 10 seconds was the longest known polar bear dive.
Vencl says he expects the Guinness Book of Records to confirm the record after viewing video footage. The records book requires ice to be at least a foot thick and does not allow diving suits. Vencl swam from one hole cut in the ice to another, though there were holes cut in the ice at intervals to give him the option of emerging earlier. "Safety is naturally first. It's not like I dive into a hole and they wait if I manage to find the other one," he told AFP while training earlier this month. He said his training included taking freezing baths and wearing light clothes even in very cold weather. (Read more swimming stories.)