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Webbed feet are the result of mutations in genes that normally cause interdigital tissue between the toes to apoptose. [8] Apoptosis, or programmed cell death, in development is mediated by a variety of pathways, and normally causes the creation of digits by death of tissue separating the digits.
Webbed toes is the informal and common name for syndactyly affecting the feet—the fusion of two or more digits of the feet. This is normal in many birds, such as ducks; amphibians, such as frogs; and some mammals, such as kangaroos.
Simple syndactyly can be full or partial, and is present at birth (congenital). In early human fetal development, webbing (syndactyly) of the toes and fingers is normal. At about 6 weeks of gestation, apoptosis takes place due to a protein named sonic hedgehog , also known as SHH, which dissolves the tissue between the fingers and toes, and the ...
An example of interdigital webbing on an Abah River flying frog.. In oryzomyines, a mainly South American rodent group, the marsh rice rat, Pseudoryzomys simplex, and Sigmodontomys alfari all have small webs, which do not extend to the end of the proximal phalanges, whereas Amphinectomys savamis, Lundomys molitor and the members of the genera Holochilus and Nectomys have more expansive webbing ...
As traditionally—but erroneously—defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such names as totipalmates or steganopodes . Most have a bare throat patch (gular patch), and the nostrils have evolved into dysfunctional slits, forcing them to breathe through their mouths.
Typically, true frogs are smooth and moist-skinned, with large, powerful legs and extensively webbed feet. The true frogs vary greatly in size, ranging from small—such as the wood frog (Lithobates sylvatica)—to large. Many of the true frogs are aquatic or live close to water. Most species lay their eggs in the water and go through a tadpole ...
Most have sharp claws on their feet and all except the sea otter have long, muscular tails. The 13 species range in adult size from 0.6 to 1.8 m (2.0 to 5.9 ft) in length and 1 to 45 kg (2.2 to 99.2 lb) in weight.
They have stout legs and webbed feet, with the web connecting all four toes. In some species, the webs are brightly colored and used in courtship displays . The bill is usually conspicuously colored, long, deep at the base, and pointed, with saw-like edges.