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Scale (anatomy) facts for kids

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Keeled scales on a southern watersnake (26954310414)
Keeled scales of a colubrid snake (banded water snake; Nerodia fasciata)



Fish scales


Cosmoid scales


Ganoid scales

Ganoid scales
Ganoid scales on a carboniferous fish Amblypterus striatus

Ganoid scales can be found on gars (family Lepisosteidae), bichirs, and reedfishes (family Polypteridae). Ganoid scales are similar to cosmoid scales, but a layer of ganoin lies over the cosmine layer and under the enamel. Ganoin scales are diamond shaped, shiny, and hard. Within the ganoin are guanine compounds, iridescent derivatives of guanine found in a DNA molecule. The iridescent property of these chemicals provide the ganoin its shine.

Placoid scales

Denticules cutanés du requin citron Negaprion brevirostris vus au microscope électronique à balayage
Placoid scales on a lemon shark (Negaprion brevirostris)


Leptoid scales


Cycloid scales on a common roach (Rutilus rutilus)

Reptilian scales

Gold Dust Day Gecko closeup hawaii edit 1
Brightly colored scales on a gold dust day gecko


The scales of all reptiles have an epidermal component (what one sees on the surface), but many reptiles, such as crocodilians and turtles, have osteoderms underlying the epidermal scale. Such scales are more properly termed scutes. Snakes, tuataras and many lizards lack osteoderms. All reptilian scales have a dermal papilla underlying the epidermal part, and it is there that the osteoderms, if present, would be formed.

Avian scales

Riesenseeadler Fang
Scales on talons of a Steller's sea eagle (Haliaeetus pelagicus)

Birds' scales are found mainly on the toes and metatarsus, but may be found further up on the ankle in some birds. The scales and scutes of birds were thought to be homologous to those of reptiles, but are now agreed to have evolved independently, being degenerate feathers.

Mammalian scales


On the other hand, the musky rat-kangaroo, has scales on its feet and tail. The precise nature of its purported scales has not been studied in detail, but they appear to be structurally different from pangolin scales.

Anomalures also have scales on their tail undersides.

Foot pad epidermal tissues in most mammal species have been compared to the scales of other vertebrates. They are likely derived from cornification processes or stunted fur much like avian reticulae are derived from stunted feathers.

Arthropod scales

Luna moth scales
Scales on a luna moth (Actias luna)


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Scale (anatomy) Facts for Kids. Kiddle Encyclopedia.