First, there's Suberites ambulodomos, or the "walking sponge." This animal forms a unique partnership with hermit crabs. It settles on the tiny shell of a very young hermit crab. As the sponge ...

The hermit crab has a soft abdomen which it protects by occupying shells left empty ... This trick reduces the chance of being attacked by predators, who think the seakrait is looking right at them. A ...