Pruney fingertips aren't swollen sponges — the wrinkles actually come from blood vessels constricting and pulling skin inward.

A new fossil and DNA analysis traces how dozens of sloth species responded to climate shifts and humans. Just two small tree-dwelling sloths remain today.

The person who received the bladder is doing well, and the successful transplant could offer hope to thousands of people with bladder dysfunction.

Experts explain the science behind Biden's advanced prostate cancer diagnosis, including how common it is and what treatments are available.

Penguin poop provides ammonia for cloud formation in coastal Antarctica, potentially helping to mitigate the impacts of climate change in the region.