Dewlap

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A mastiff with a dewlap, seen connecting from the neck to the lower jaw. Mastif angielski pregowany 768.jpg
A mastiff with a dewlap, seen connecting from the neck to the lower jaw.

A dewlap is a longitudinal flap of skin or similar flesh that hangs beneath the lower jaw or neck of many vertebrates. 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 of a frog. More generally, it can be any hanging mass of skin, such as a fold of loose skin on an elderly person's neck, or the wattle of a bird. Dewlaps can be considered as a caruncle, defined as "a small, fleshy excrescence that is a normal part of an animal's anatomy". [1]

Contents

Etymology

The word is first attested in the mid 1300s as dewelappe ("fold of skin that hangs from the throat of oxen and kine"), from lappe ("loose piece", from Old English læppa ), but the first element *dew(e)- is of nebulous origin and meaning; it probably was altered by folk etymology with "dew". Old English had fræt-læppa in the aforementioned sense (and Middle English fresh-lappe). There also seems to be a cognate to Danish dialectal doglæp ("flap of skin that sweeps dew from grass, especially on the neck of an ox"), [2] but this might be a parallel independent development.

From the 1580s onward, it was applied to the fleshy fold or wattle of a turkey and also to a flaccid, elderly human throat. [3]

Mammals

A zebu with a large dewlap. Bos taurus indicus.jpg
A zebu with a large dewlap.

Many mammals such as dogs, rabbits and moose possess dewlaps. In zebu cattle, the dewlap is colloquially known as the "briefcase folds".[ citation needed ] The dewlap is also seen in both sexes of moose.

Rabbits

A palomino rabbit displaying her dewlap beside a month-old kit Palomino rabbit with kit.jpg
A palomino rabbit displaying her dewlap beside a month-old kit

In rabbits, the dewlap is a secondary sex characteristic of female rabbits which grows once the doe reaches sexual maturity. In laboratory conditions, when a butyl alcohol extract of the urine of pregnant women was administered to male rabbits, they developed a dewlap, which then gradually disappeared once the administration ceased. If a female rabbit is ovarectomized before reaching maturity, the dewlap never develops, and even when an ovarectomy is performed on a mature female rabbit with a dewlap, the dewlap disappears gradually afterwards. [4] Near the end of pregnancy, the female rabbit will pluck fur from the dewlap to line a nest for her young. [5]

Reptiles and birds

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

Many reptiles have dewlaps, most notably the anole family and Sitana genus of lizards, 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. [6] 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 carotenoids. 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. [7] 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. [8] 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.

An iguana with an extended dewlap. Iguana Dewlap Labeled.png
An iguana with an extended dewlap.

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

See also

Related Research Articles

<span class="mw-page-title-main">Dactyloidae</span> Family of reptiles

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 subfamily, Dactyloidae, of the family Iguanidae. In the past they were included in the family Polychrotidae together with Polychrus, but the latter genus is not closely related to the true anoles.

<i>Anolis</i> Genus of lizards

Anolis is a genus of anoles, iguanian lizards in the family Dactyloidae, native to the Americas. With more than 425 species, it represents the world's most species-rich amniote tetrapod genus, although many of these have been proposed to be moved to other genera, in which case only about 45 Anolis species remain. Previously, it was classified under the family Polychrotidae that contained all the anoles, as well as Polychrus, but recent studies place it in the Dactyloidae.

<i>Anolis carolinensis</i> Species of reptile

Anolis carolinensis or green anole is a tree-dwelling species of anole lizard native to the southeastern United States and introduced to islands in the Pacific and Caribbean. A small to medium-sized lizard, the green anole is a trunk-crown ecomorph and can change its color to several shades from brown to green.

<span class="mw-page-title-main">Brown anole</span> Species of lizard

The brown anole, also known commonly as the Cuban brown anole, or De la Sagra's anole, is a species of lizard in the family Dactyloidae. The species is native to Cuba and the Bahamas. It has been widely introduced elsewhere, via the importation and exportation of plants where the anole would lay eggs in the soil of the pots, and is now found in Florida and as far north in the United States as southern Georgia, Texas, Louisiana, Tennessee, Mississippi, Alabama, Hawaii, and Southern California. It has also been introduced to other Caribbean islands, Mexico, and Taiwan.

<span class="mw-page-title-main">Knight anole</span> Species of lizard

The knight anole is the largest species of anole in the Dactyloidae family. Other common names include Cuban knight anole or Cuban giant anole, highlighting its native country, but it has also been introduced to Florida. In its native Cuba, this large anole is called chupacocote.

<span class="mw-page-title-main">Wattle (anatomy)</span> Fleshy growth on the head or neck of a bird

A wattle is a fleshy caruncle hanging from various parts of the head or neck in several groups of birds and mammals. Caruncles in birds include those found on the face, wattles, dewlaps, snoods, and earlobes. Wattles are generally paired structures, but may occur as a single structure when it is sometimes known as a dewlap. Wattles are frequently organs of sexual dimorphism. In some birds, caruncles are erectile tissue and may or may not have a feather covering.

<span class="mw-page-title-main">Blue anole</span> Species of lizard

The blue anole is a species of lizard in the family Dactyloidae. A. gorgonae falls into the genus Dactyloa, which are all highly arboreal, but differ in size, coloration, and perch preferences. The blue anole specifically occupies higher perches. It is a small species which is "near threatened" and found only on the island of Gorgona, in the Colombian Pacific.

<i>Anolis cristatellus</i> Species of reptile

Anolis cristatellus is a small species of anole, belonging to the Dactyloidae family of reptiles. The species is native to Puerto Rico and the U.S. and British Virgin Islands, with introduced populations in locations around the Caribbean. The males of A. cristatellus are easily recognizable by the fin running down the top of the tail, which is known as a "caudal crest". The females also have this crest, but it is smaller than that of the males. The species is often quite common in many areas on Puerto Rico, where it can be seen during the day passing the time on the lower parts of tree trunks, or on fences and the walls of buildings in urban areas, sometimes venturing down onto the ground in order to lay eggs, have a snack, or do other cursorial activities. Like many anoles, this species displays the characteristic behaviour of doing push-ups as well as inflating a pizza-like flap of coloured skin on its throat, known as a dewlap, in order to show others how dominant it is, and thus attract mates or intimidate rivals.

<i>Anolis occultus</i> Species of reptile

The Puerto Rican twig anole or dwarf anole is a species of small, arboreal anole endemic to Puerto Rico and primarily inhabiting the Cordillera Central from the Sierra de Cayey range in the Southeast to the central-western ranges of Maricao. A mostly grey to olive-brown bodied lizard, A. occultus is the smallest of the Puerto Rican anoles with a snout to vent length of 34–42 mm. In comparison to other twig anoles, A. occultus is extremely cryptic through its unique sleeping behaviors and mottled pattern. Sleeping behavior including site selection minimizes the probability of predator encounter along with A. occultus' extensive list of antipredator behaviors.

<span class="mw-page-title-main">Caruncle (bird anatomy)</span> Fleshy growth on the head or neck of a bird

A caruncle is defined as 'a small, fleshy excrescence that is a normal part of an animal's anatomy'. Within this definition, caruncles in birds include wattles, combs, snoods, and earlobes. The term caruncle is derived from Latin caruncula, the diminutive of carō, "flesh".

<i>Anolis grahami</i> Species of lizard

Anolis grahami, commonly known as the Jamaican turquoise anole and Graham's anole, is a species of lizard in the family Dactyloidae. The species is native to the island of Jamaica, and has also been introduced to the territory of Bermuda. It is one of many different species of anole lizards found in Jamaica. There are two recognized subspecies.

<i>Anolis cuvieri</i> Species of reptile

Anolis cuvieri is a species of lizard in the family Dactyloidae. The species is endemic to Puerto Rico, and is common in the Toro Negro State Forest.

<i>Anolis proboscis</i> Species of lizard

Anolis proboscis, commonly known as the horned anole, Ecuadorian horned anole or Pinocchio lizard, is a small anole lizard in the family Dactyloidae. A single male specimen was discovered in 1953 in Ecuador and formally described by Peters and Orces in 1956, but the species then went unreported until its rediscovery in 2004. Its currently known habitat is a small stretch of vegetation along an Ecuadorian highway. It has been classified as Endangered by the IUCN due to its restricted distribution and ongoing habitat loss.

<i>Anolis podocarpus</i> Species of lizard

Anolis podocarpus is a species of anole lizard in the family Dactyloidae. It was first described by Fernando P. Ayala-Varela and Omar Torres-Carvajal in 2010, the type locality being the Podocarpus National Park at Romerillos Alto in Zamora-Chinchipe Province, Ecuador on the southeastern slopes of the Andes. The specific name refers to the Podocarpus trees which are found in the Park.

<i>Anolis stratulus</i> Species of reptile

Anolis stratulus is a moderately-sized species of anole found in Puerto Rico, the United States Virgin Islands and the British Virgin Islands. It is a gray-colored lizard spotted with brown markings. It is arboreal, usually found positioned on tree bark on branches in the canopies of forest trees, where in some areas of Puerto Rico it can be incredibly abundant, with tens of thousands of the lizards being present per hectare.

<i>Anolis vermiculatus</i> Species of lizard

The Vinales anole, also known as the Cuban stream anole, is a species of lizard in the family Dactyloidae, endemic to Cuba.

<i>Anolis eugenegrahami</i> Species of lizard

Anolis eugenegrahami, the Eugene's anole or the black stream anole, is a critically endangered species of lizard in the family Dactyloidae. This semi-aquatic species is endemic to northern Haiti.

<i>Anolis aquaticus</i> Species of reptile

Anolis aquaticus, commonly known as the water anole, is a semi-aquatic species of anole, a lizard in the family Dactyloidae, native to southwestern Costa Rica and far southwestern Panama. The species demonstrates adaptations that allows it to spend periods of time underwater up to approximately a quarter of an hour, forming an air bubble which clings to its head and serves to recycle the animal's air supply while it spends time beneath the surface. Although highly unusual, similar adaptions and behavior are found in other species of semi-aquatic anoles.

<i>Anolis auratus</i> Species of lizard

Anolis auratus, the grass anole, is a species of lizard in the family Dactyloidae. The species is found in Costa Rica, Panama, Venezuela, Colombia, French Guiana, Guyana, and Brazil.

<i>Anolis evermanni</i> Species of lizard

Anolis evermanni, also known commonly as the emerald anole, Evermann's anole, and the small green anole, is a species of lizard included within the family Dactyloidae. A. evermanni is native to Puerto Rico, where it is mainly found in wet forests. A. evermanni is a medium-sized lizard and bright emerald-green in color. A. evermanni is studied for its behavior as well as the evolution of the family Dactyloidae. The group of lizards which are member species of the family Dactyloidae are known as anoles. Anoles are found throughout the Americas and are related to iguanas.

References

  1. Lexic.us. "Definition of caruncle" . Retrieved April 20, 2013.
  2. "doglæp — Den Danske Ordbog". ordnet.dk. Retrieved 2022-03-25.
  3. Harper, Douglas R. "dewlap (n.)". Online Etymological Dictionary.
  4. Hu, C.-k.; Frazier, C. N. (1938-02-01). "Relationship Between Female Sex Hormone and Dewlap in the Rabbit". Experimental Biology and Medicine. 38 (1): 116–119. doi:10.3181/00379727-38-9761. ISSN   1535-3702. S2CID   87987542.
  5. Vennen, Kristine M.; Mitchell, Mark A. (2009-01-01), Mitchell, Mark A.; Tully, Thomas N. (eds.), "Rabbits", Manual of Exotic Pet Practice, Saint Louis: W.B. Saunders: 375–405, doi:10.1016/b978-141600119-5.50017-2, ISBN   978-1-4160-0119-5, PMC   7152457
  6. Sigmund, William R. (1983-01-01). "Female Preference for Anolis carolinensis Males as a Function of Dewlap Color and Background Coloration". Journal of Herpetology. 17 (2): 137–143. doi:10.2307/1563454. JSTOR   1563454.
  7. Steffen, John E.; McGraw, Kevin J. (2007-01-01). "Contributions of pterin and carotenoid pigments to dewlap coloration in two anole species". Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology. 146 (1): 42–46. doi:10.1016/j.cbpb.2006.08.017. PMID   17056290.
  8. Font, Enrique (1991-11-26). "Localization of brainstem motoneurons involved in dewlap extension in the lizard, Anolis equestris". Behavioural Brain Research. 45 (2): 171–176. doi:10.1016/S0166-4328(05)80082-8. PMID   1789924. S2CID   4031506.