Watch sponges breathe out neon green water like they're smoking

There's something completely fascinating in something so incredibly simple. Sponges—animals that can't walk or swim—are incredibly efficient at what they do and have a super fun history to them too. Watch Jonathan Bird explain how sponges work and where they come from in this Blue World clip. » 6/05/14 9:05pm 6/05/14 9:05pm