Dewlap

Mas angielski pregowany 768

Bos taurus indicus

Palomino rabbit with kit

File:Blue-Eyed Anole, Corcovado Natl Park, Costa Rica.ogv

Iguana Dewlap Labeled

Dewlap refers to a fold of loose skin that hangs beneath the lower jaw or neck of many vertebrates, including some types of birds, reptiles, and mammals. The presence and size of the dewlap can vary greatly among species, and it can serve several functions, ranging from sexual selection to thermoregulation.

Function

The primary functions of the dewlap include sexual selection, species identification, and thermoregulation. In many species, the dewlap is more prominent in males and may be used in sexual displays to attract mates or assert dominance. For example, in some lizard species, males will extend their dewlap to display its size and coloration during mating rituals or territorial disputes. The dewlap can also serve as a visual signal for species or individual identification among animals.

In addition to its role in communication, the dewlap has been suggested to play a part in thermoregulation for some species. The large surface area of the dewlap can facilitate heat exchange with the environment, helping the animal to cool down in hot climates.

Anatomical Features

The structure of the dewlap varies among different species. In reptiles, such as Anolis lizards, the dewlap consists of a flap of skin that can be extended or retracted. This extension is controlled by specialized muscles, bones, or cartilage that allow the dewlap to be displayed prominently when needed.

In mammals, such as certain breeds of cattle and dogs, the dewlap is often a permanent feature that does not retract. It may serve as a protective layer, cushioning the throat and chest from injuries during fights or from the environment.

Evolutionary Significance

The evolutionary development of the dewlap is believed to be driven by sexual selection and ecological factors. The variation in dewlap size, color, and shape among species and within species can be attributed to the differing selective pressures in their respective environments. For instance, in environments where visual signals are crucial for mating success, the dewlap may be more pronounced and colorful.

Examples

- In the Anolis lizards, the dewlap is used in territorial and mating displays. - Certain breeds of cattle, such as the Brahman, have a prominent dewlap that may help in heat dissipation. - The American bullfrog has a dewlap that plays a role in its vocalizations and mating calls.

Conservation and Study

The study of dewlaps contributes to our understanding of animal behavior, evolutionary biology, and ecology. Observing changes in dewlap characteristics can also be an indicator of environmental changes or pressures. Conservation efforts for species with prominent dewlaps often consider the ecological roles and habitats that support the behaviors associated with dewlap display and function.