This National Geographic video taken by researchers using a shell-mounted "crittercam," capturing rare footage of a giant river turtle in Brazil's Amazon basin interacting with its hatchlings underwater.

Also recommended: this NatGeo video charting the surprisingly difficult task of attaching a crittercam to a manatee, because the sight of a manatee briskly and matter-of-factly removing a camera harness is too good not to share.

[Via Mental Floss]