Gill: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Photos and Videos

sand tiger shark (Carcharias taurus)

Illustration showing different animals and their respiratory organs: a spider with book lungs, a chicken with lungs, a sponge with labeled inflow and outflow pores, a fish with gills, and a caterpillar with spiracles.

Axolotl wearing a green paper hat in the style of Peter Pan, with speech bubble reading “I'll never grow up!”

Study the roles of a fish's scales, swim bladder, and gills in its respiratory system

See All Videos and Images →

Topics

How do gills work?book gill gill pouch gill lamella gill slit Branchial arch ctenidium hyoid arch gill septum lamellibranch ctenidium spiracle Air sac human respiratory system trachea