Alligators can stay underwater for up to 24 hours if they need to, although most only stay submerged for 20 to 30 minutes. The alligator's body is specially developed to stay beneath the water if the circumstances call for it.
The alligator is adept at controlling and slowing down its heart rate. Alligators are not equipped with gills, so they don't breathe under the water. When an alligator goes beneath the water, a flap closes off its ears and nostrils. This lets more blood and oxygen make it through to its vital organs even though the alligator is not breathing.