Short Wave: When Critters Bleed ... On Purpose!

Some insects and reptiles have a strange self-preservation characteristic — they suddenly start bleeding from places like their eyes or knees.

Scientist Sebastian Hoefer says, “It really does look like it’s deliberate. Deliberately, it’s bleeding to put this show on.”

A show put on to deter any would-be predators. NPR science correspondent Nell Greenfieldboyce looks at “reflex bleeding” and explores some of the creatures that bleed on purpose.

For more science reporting and stories, follow Nell on twitter @nell_sci_NPR. And, as always, email us at

This episode was produced by Thomas Lu, edited by Gisele Grayson, and fact-checked by Ariela Zebede.


Short Wave Podcast

It’s science for everyone, using a lot of creativity and a little humor. Join host Maddie Sofia for science on a different wavelength.

Biology, Zoology
Insects, Reptiles
Middle School, High School

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