Top 10 Scientific Discoveries of 2013

Cancer-free Naked Mole Rats
These funny-looking eusocial rodents could wind up teaching humans a lot about cancer. © Wolfgang_Thieme/dpa/Corbis

Small and hairless, naked mole rats are so ugly that they're cute. Unlike many rodents though, these subterranean creatures have unusually long lives (30 years!) and don't get cancer. In June, researchers at the University of Rochester announced why that is. They said naked mole rats have a natural substance in between their tissues that keeps cancerous tumors away. This substance, known as hyaluronan, may one day lead to cancer treatments in humans.

How did researchers find this out? When they removed the hyaluronan from the tissue of the mole rats, the rats began to grow tumors. Apparently, the naked mole rats have a lot of hyaluronan that keeps tissues flexible, which is essential for burrowing and making sure their skin remains unscathed. Humans produce hyaluronan, too, but in much smaller quantities [source: Chow].