 Two species, the giant mudskipper "Periophthalmodon schlosseri" and the walking goby "Scartelaos histophorus", build a special chamber at the bottom of their burrows into which they carry mouthfuls of air.Once released the air accumulates at the top of the chamber and forms a reserve from which the fish can breathe – like all amphibious fishes, mudskippers are good air breathers.If researchers experimentally extract air from the special chambers, the fish diligently replenish it.