Hydric brooding is an
egg incubation
Egg incubation is the process by which an egg, of oviparous (egg-laying) animals, develops an embryo within the egg, after the egg's formation and ovipositional release. Egg incubation is done under favorable environmental conditions, possibl ...
practice performed by some species of frogs. It involves either placing urine from the bladder on the eggs to keep them wet or holding the body over the eggs to prevent them from drying out.
Unlike reptile and bird eggs, which have an
amniotic membrane
The amnion (: amnions or amnia) is a membrane that closely covers human and various other embryos when they first form. It fills with amniotic fluid, which causes the amnion to expand and become the amniotic sac that provides a protective en ...
to prevent dehydration, amphibian eggs laid on land can become dry and die. In some species, the male frog will periodically return to the clutch and moisten the eggs with urine from his bladder. For example, the male poison arrow frog ''
Phyllobates vittatus'' sits on top of his eggs and sheds liquid. He visits the clutch roughly three times each day until hatching.
References
Reproductive system
Amphibians
Herpetology
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