These House Sparrows, one of the sixteen focal species of the Celebrate Urban Birds program, were all dust-bathing together next to the sidewalk near the Washington Monument as I walked past this week. Birds dust-bathe to clean their feathers of oils and parasites, and the behavior is well-documented in this species.

On the other side of the world, just a few days ago, footage was released of previously undocumented (but formerly observed) behavior in Philippine thresher sharks, pelagic predators with a prodigious posterior. A thresher shark’s tail comprises about half of the shark’s total length, and in the video provided by The Guardian from the Thresher Shark Project you can see how incredibly flexible and deadly these whips are.

To learn more about thresher sharks and the opportunities for citizen science volunteers to study them, visit the Thresher Shark Project.