President Donald Trump says he won't apologize for posting a racist video of the Obamas. Trump told reporters that, “I didn't make a mistake,” as he flew to Florida on Friday.

A new study comparing 59 species of primates linked same-sex sexual behavior to scarce resources and more predators in socially complex species. The findings show diverse sexual behaviors are common — and likely beneficial in primates.

Learn how repeated burn injuries may have acted as a form of natural selection, influencing human genes linked to healing and immune response.

Lemurs are known for their social grooming, but their best grooming tool is their tongue. Below their main tongue lies the sublingua—a stiff, secondary “tongue” used specifically to clean their specialized “toothcomb” teeth.