dewlap

An anole in Costa Rica repeatedly protracting and retracting its dewlap.

A Mastiff with a dewlap.

A zebu with a large dewlap.

A dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double chin or the sub-mandibular vocal sac of a frog. In a more general manner, the term refers to any pendulous mass of skin, such as a fold of loose skin on an elderly person's neck, or the wattle of a bird. There are also dewlaps on dogs such as the English Springer Spaniel, the Basset Hound and the Mastiff. A fatty "dewlap" is also found on female rabbits, such as the New Zealand white rabbit. While pregnant, the female rabbit will pluck fur from the dewlap to line a nest for her babies.^{[citation needed]} A dewlap is also found in both genders of moose.

Many reptiles have dewlaps, most notably the anole species of lizard, which have large skin dewlaps which they can extend and retract. These dewlaps are usually of a different color from the rest of their body and when enlarged they make the lizard seem much bigger than it really is, especially when warding off predators. Males use the dewlap to intimidate rivals and to attract females during the mating season. While the male anole's dewlap is much larger, the female also possess one. Lizards which have mobile dewlaps usually accompany their dewlap movement with head bobs and other displays. Scientists^[who?] are unsure about what this is meant to communicate, but it is prevalent when the lizards are courting.

Many birds also have dewlaps, such as domestic chickens, some cracids and some guans.

In Brahman cows, the dewlap is sometimes colloquially referred to as "briefcase folds."

In humans, the formation of a dewlap is prevented by the attachment of the deep cervical fascia to the hyoid bone.^{[citation needed]}

See also

• Crest
• Double chin
• Neck frill
• Wattle

References

• Weldon Owen Pty Ltd. (1993). Encyclopedia of animals - Mammals, Birds, Reptiles, Amphibians. Reader's Digest Association, Inc. ISBN 1875137491.

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