Amazing Alligator Designs: Nostril Valves

An American Alligator laying alongside the Chesser Island Boardwalk allowed ample opportunity for some close-up study. Alligator’s have upward facing nostrils at the end of the snout that allow it to breath while the body is underwater. The nostrils have flaps which close when the alligator is submerged. Okefenokee National Wildlife Refuge, Georgia, USA. November 14, 2021 ©

The American Alligator is perfectly designed for the swamp habitats that they frequent. The eyes and nostrils protrude above the plane of the snout so that the body and head can be totally submerged yet they still can see and breath.

The nostrils are positioned on a fleshy mound at the tip of the alligator’s snout. The nostrils can close like a valve when submerging to prevent breathing in water. Sensitive nerve endings around the nostrils signal the alligator to close its nostrils as they touch the water’s surface.  In the colder winter months, a gator may submerged for days with just its nostrils poking above the surface.

  • Ouchley, K.. American Alligator: Ancient Predator in the Modern World. University Press of Florida, 2013.
  • Vliet, Kent, and Wayne Lynch. Alligators: The Illustrated Guide to Their Biology, Behavior, and ConservationIllustrated, Johns Hopkins University Press, 2020.

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