A dewlap is a longitudinal flap of

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

or similar flesh that hangs beneath the

lower jaw In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

of many

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with ...

s. More loosely, it can be various similar structures in the neck area, such as those caused by a double chin or the submandibular

vocal sac The vocal sac is the flexible membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the vocal sac is one way ...

of a

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

. More generally, it can be any hanging mass of skin, such as a fold of loose skin on an elderly

person A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of prope ...

's neck, or the wattle of a

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

. Dewlaps can be considered as a ''caruncle'', defined as "a small, fleshy excrescence that is a normal part of an animal's anatomy".

Etymology

The word is first attested in the mid 1300s as ''dewelappe'' ("fold of skin that hangs from the throat of oxen and

kine Kine or KINE may refer to: Radio and TV stations * KINE-FM, a radio station (105.1 FM) licensed to Honolulu, Hawaii, United States * KINE (AM), a radio station (1330 AM) licensed to Kingsville, Texas, United States * KINE-LP, a defunct low-pow ...

"), from ''lappe'' ("loose piece", from

Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlers in the mid-5th ...

), but the first element ''*dew(e)-'' is of nebulous origin and meaning; it probably was altered by

folk etymology Folk etymology (also known as popular etymology, analogical reformation, reanalysis, morphological reanalysis or etymological reinterpretation) is a change in a word or phrase resulting from the replacement of an unfamiliar form by a more famili ...

with " dew". Old English had ''fræt-læppa'' in the aforementioned sense (and

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old Englis ...

''fresh-lappe''). There also seems to be a

cognate In historical linguistics, cognates or lexical cognates are sets of words in different languages that have been inherited in direct descent from an etymological ancestor in a common parent language. Because language change can have radical ef ...

to Danish dialectal ("flap of skin that sweeps dew from grass, especially on the neck of an ox"), but this might be a parallel independent development. From the 1580s onward, it was applied to the fleshy fold or wattle of a

turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula ...

and also to a flaccid, elderly human throat.

Mammals

Many mammals such as dogs,

rabbit Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit sp ...

s and

moose The moose (in North America) or elk (in Eurasia) (''Alces alces'') is a member of the New World deer subfamily and is the only species in the genus ''Alces''. It is the largest and heaviest extant species in the deer family. Most adult ma ...

possess dewlaps. In

zebu The zebu (; ''Bos indicus'' or ''Bos taurus indicus''), sometimes known in the plural as indicine cattle or humped cattle, is a species or subspecies of domestic cattle originating in the Indian sub-continent. Zebu are characterised by a fatty h ...

cattle, the dewlap is colloquially known as the "briefcase folds". The dewlap is 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. The dewlap is also seen in both sexes of

Reptiles and birds

Many reptiles have dewlaps, most notably the

anole Dactyloidae are a family of lizards commonly known as anoles () and native to warmer parts of the Americas, ranging from southeastern United States to Paraguay. Instead of treating it as a family, some authorities prefer to treat it as a subfami ...

family of

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia altho ...

s, which have large skin dewlaps they can extend and retract. The anole family has been found to have enhanced vision for color and depth perception. This family is able to see dewlap coloration from a distance, giving the dewlap use and importance. These dewlaps are usually of a different color from the rest of their body and, when enlarged, make the lizard seem much bigger than it really is. The dewlap is primarily used when indicating territorial boundaries and for males to attract females during the mating season. The pigments generating this color are pterins and

carotenoid Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, ...

s. These two pigments are the most easily seen through the anole's eyes. Pterin and carotenoid pigments are located throughout the tissue of the dewlap, creating yellow and red hues. Lizards usually accompany dewlap movement with head bobs and other displays. The dewlap moves through extension and contraction. The muscles creating this movement are the ceratohyoid muscles and are connected to the hyoid apparatus in the throat and larynx area. Though the purpose of these displays is unclear, the colors of the dewlap and the movements during the displays are thought to be a way of standing out against visual background noise. Iguana Dewlap Labeled

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

References

External links

* * Weldon Owen Pty Ltd. (1993). ''Encyclopedia of animals — Mammals, Birds, Reptiles, Amphibians.'' Reader's Digest Association, Inc. {{ISBN, 1-875137-49-1 Vertebrate anatomy Skin anatomy Articles containing video clips

Etymology

Mammals

Reptiles and birds

See also

References

External links