Dermal pressure receptors (DPRs) are dotted sensory pits found on the scales of animals in the Crocodilia order, which includes alligators, caimans, and crocodiles. Animals in the Alligatorinae family of this order only have the pits in the head area, mainly along the jawline, eyes, nose and upper palate. Animals in the Crocodylidae and Gavialinae families have them distributed over their entire bodies.
Before being given their current name, these sensory receptors were called integumentary sense organs (ISOs) because of their location in the integumentary or outer layer of the skin. Along the jaw line, they resemble black beard stubble and there may be as many as three or four receptors at the outer edges of a single scale. On other areas of the body, such as the belly of a crocodile, DPRs are often white, and there may only be one per scale.
Dermal pressure receptors are not well understood, but it is assumed that their function differs depending on where they are located on the animal's body. Those on the head are very sensitive to the slightest changes in pressure from surrounding water. When a fish swims within close proximity, for example, the disturbance creates tiny waves that impinge on the receptors. The sensation alerts the crocodile or alligator of not only the presence but the precise location of prey, even in murky water where vision is poor. At the surface when languidly resting with eyes and nostrils exposed, an animal might instantly thrash out and catch underwater prey that was otherwise entirely undetectable.
Alligators are mainly found in fresh water while crocodiles live in brackish or salt water, leading some researchers to theorize that the dermal pressure receptors covering the crocodile's body might be involved in chemical reception or salinity detection, but there is no conclusive evidence.
After surviving nearly 200 million years virtually unchanged, crocodile and alligator skin became popular in the 1900s, which led to hunting the animals nearly to extinction. Due to conservationists efforts, alligators have recovered and regulated trade of skins is legal once again. Crocodiles remain on the endangered species list, however. If buying boots, belts or other items advertised as alligator skin, there should be no sign of these receptors, as the skin comes from the belly where they are not found on this animal. If they are present on some or all of the scales, the item is not made from alligator skin.
Dermal pressure receptors (DPRs) are dotted sensory pits found on the scales of animals in the Crocodilia order, which includes alligators, caimans, and crocodiles. Animals in the Alligatorinae family of this order only have the pits in the head area, mainly along the jawline, eyes, nose and upper palate. Animals in the Crocodylidae and Gavialinae families have them distributed over their entire bodies.
Before being given their current name, these sensory receptors were called integumentary sense organs (ISOs) because of their location in the integumentary or outer layer of the skin. Along the jaw line, they resemble black beard stubble and there may be as many as three or four receptors at the outer edges of a single scale. On other areas of the body, such as the belly of a crocodile, DPRs are often white, and there may only be one per scale.
Dermal pressure receptors are not well understood, but it is assumed that their function differs depending on where they are located on the animal's body. Those on the head are very sensitive to the slightest changes in pressure from surrounding water. When a fish swims within close proximity, for example, the disturbance creates tiny waves that impinge on the receptors. The sensation alerts the crocodile or alligator of not only the presence but the precise location of prey, even in murky water where vision is poor. At the surface when languidly resting with eyes and nostrils exposed, an animal might instantly thrash out and catch underwater prey that was otherwise entirely undetectable.
Alligators are mainly found in fresh water while crocodiles live in brackish or salt water, leading some researchers to theorize that the dermal pressure receptors covering the crocodile's body might be involved in chemical reception or salinity detection, but there is no conclusive evidence.
After surviving nearly 200 million years virtually unchanged, crocodile and alligator skin became popular in the 1900s, which led to hunting the animals nearly to extinction. Due to conservationists efforts, alligators have recovered and regulated trade of skins is legal once again. Crocodiles remain on the endangered species list, however. If buying boots, belts or other items advertised as alligator skin, there should be no sign of these receptors, as the skin comes from the belly where they are not found on this animal. If they are present on some or all of the scales, the item is not made from alligator skin.