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.

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

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

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

In a first-of-its-kind test, scientists used a levitated magnet to search for dark matter, the unidentified substance believed to be present throughout the cosmos. If dark matter is made up of ...

Scientists suggest the missile defense plan will face big hurdles, especially given its projected timeline and cost.