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منذ 8 ساعات نشر في ٢٠٢٦/٠٦/١٣ م

Some neotenic species such as the mudpuppy (Necturus maculosus) retain their gills throughout their lives, but most species lose them at metamorphosis. The embryos of some terrestrial lungless salamanders, such as Ensatina, that undergo direct development, have large gills that lie close to the egg's surface.

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منذ 1 أيام نشر في ٢٠٢٦/٠٦/١٢ م

Respiration differs among the different species of salamanders, and can involve gills, lungs, skin, and the membranes of mouth and throat. Larval salamanders breathe primarily by means of gills, which are usually external and feathery in appearance. Water is drawn in through the mouth and flows out through the gill slits.

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منذ 2 أيام نشر في ٢٠٢٦/٠٦/١١ م

Similar clicking behaviour was observed in two European newts Lissotriton vulgaris and Ichthyosaura alpestris in their aquatic phase.

Vocalization in salamanders has been little studied and the purpose of these sounds is presumed to be the startling of predators.

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منذ 3 أيام نشر في ٢٠٢٦/٠٦/١٠ م

The arboreal salamander can squeak using a different mechanism; it retracts its eyes into its head, forcing air out of its mouth. The ensatina salamander occasionally makes a hissing sound, while the sirens sometimes produce quiet clicks, and can resort to faint shrieks if attacked.

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منذ 5 أيام نشر في ٢٠٢٦/٠٦/٠٨ م

Most salamanders lack vocal cords, but a larynx is present in the mudpuppy (Necturus) and some other species, and the Pacific giant salamanders and a few others have a large larynx and bands known as plicae vocales. The California giant salamander can produce a bark or rattle, and a few species can squeak by contracting muscles in the throat.

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منذ 1 أسابيع نشر في ٢٠٢٦/٠٦/٠٦ م

Salamanders are usually considered to have no voice and do not use sound for communication in the way that frogs do. Before mating, they communicate by pheromone signaling; some species make quiet ticking, clicking, squeaks or popping noises, perhaps by the opening and closing of valves in the nose.

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منذ 1 أسابيع نشر في ٢٠٢٦/٠٦/٠٥ م

The system seems able to detect low-frequency vibrations (500–600 Hz), which may be picked up from the ground by the fore limbs and transmitted to the inner ear. These may serve to warn the animal of an approaching predator.

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منذ 2 أسابيع نشر في ٢٠٢٦/٠٥/٢٩ م

All salamanders lack middle ear cavity, eardrum and eustachian tube, but have an opercularis system like frogs, and are still able to detect airborne sound.
The opercularis system consists of two ossicles: the columella (equivalent to the stapes of higher vertebrates) which is fused to the skull, and the operculum. An opercularis muscle connects the latter to the pectoral girdle, and is kept under tension when the animal is alert.

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منذ 2 أسابيع نشر في ٢٠٢٦/٠٥/٢٨ م

Fully terrestrial species such as the fire salamander have a flatter lens which can focus over a much wider range of distances.
To find their prey, salamanders use trichromatic color vision extending into the ultraviolet range, based on three photoreceptor types that are maximally sensitive around 450, 500, and 570 nm.
The larvae, and the adults of some highly aquatic species, also have a lateral line organ, similar to that of fish, which can detect changes in water pressure.

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منذ 2 أسابيع نشر في ٢٠٢٦/٠٥/٢٧ م

The eyes of most salamanders are adapted primarily for vision at night. In some permanently aquatic species, they are reduced in size and have a simplified retinal structure, and in cave dwellers such as the Georgia blind salamander, they are absent or covered with a layer of skin. In amphibious species, the eyes are a compromise and are nearsighted in air and farsighted in water.

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منذ 3 أسابيع نشر في ٢٠٢٦/٠٥/٢٥ م

In plethodonts, the sensory epithelium of the vomeronasal organs extends to the nasolabial grooves, which stretch from the nostrils to the corners of the mouth. These extended areas seem to be associated with the identification of prey items, the recognition of conspecifics, and the identification of individuals.

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منذ 3 أسابيع نشر في ٢٠٢٦/٠٥/٢٣ م

Olfaction in salamanders plays a role in territory maintenance, the recognition of predators, and courtship rituals, but is probably secondary to sight during prey selection and feeding. Salamanders have two types of sensory areas that respond to the chemistry of the environment. Olfactory epithelium in the nasal cavity picks up airborne and aquatic odors, while adjoining vomeronasal organs detect nonvolatile chemical cues, such as tastes in the mouth.

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منذ 3 أسابيع نشر في ٢٠٢٦/٠٥/٢٠ م

Mature adults of some salamander species have "nuptial" glandular tissue in their cloacae, at the base of their tails, on their heads or under their chins. Some females release chemical substances, possibly from the ventral cloacal gland, to attract males, but males do not seem to use pheromones for this purpose.

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منذ 4 أسابيع نشر في ٢٠٢٦/٠٥/١٩ م

Some salamander toxins are particularly potent. For example, the rough-skinned newt (Taricha granulosa) produces the neurotoxin tetrodotoxin, the most toxic nonprotein substance known. Handling the newts does no harm, but ingestion of even a minute fragment of skin is deadly. In feeding trials, fish, frogs, reptiles, birds, and mammals were all found to be susceptible.

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منذ 4 أسابيع نشر في ٢٠٢٦/٠٥/١٨ م

Glands in the skin discharge mucus which keeps the skin moist, an important factor in skin respiration and thermoregulation. The sticky layer helps protect against bacterial infections and molds, reduces friction when swimming, and makes the animal slippery and more difficult for predators to catch. Granular glands scattered on the upper surface, particularly the head, back, and tail, produce repellent or toxic secretions.

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منذ 4 أسابيع نشر في ٢٠٢٦/٠٥/١٦ م

When the front limbs have been worked clear, a series of body ripples pushes the skin toward the rear. The hind limbs are extracted and push the skin farther back, before it is eventually freed by friction as the salamander moves forward with the tail pressed against the ground. The animal often then eats the resulting sloughed skin.

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منذ 4 أسابيع نشر في ٢٠٢٦/٠٥/١٥ م

The skin of salamanders, in common with other amphibians, is thin, permeable to water, serves as a respiratory membrane, and is well-supplied with glands. It has highly cornified outer layers, renewed periodically through a skin shedding process controlled by hormones from the pituitary and thyroid glands. During moulting, the skin initially breaks around the mouth, and the animal moves forward through the gap to shed the skin.

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منذ 4 أسابيع نشر في ٢٠٢٦/٠٥/١٤ م

The tail is used in courtship and as a storage organ for proteins and lipids. It also functions as a defense against predation, when it may be lashed at the attacker or autotomized when grabbed. Unlike frogs, an adult salamander is able to regenerate limbs and its tail when these are lost.

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منذ 1 شهور نشر في ٢٠٢٦/٠٥/١٣ م

In the families Ambystomatidae and Salamandridae, the male's tail, which is larger than that of the female, is used during the amplexus embrace to propel the mating couple to a secluded location. In terrestrial species, the tail moves to counterbalance the animal as it runs, while in the arboreal salamander and other tree-climbing species, it is prehensile. The tail is also used by certain plethodontid salamanders that can jump, to help launch themselves into the air.

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منذ 1 شهور نشر في ٢٠٢٦/٠٥/١٢ م

When ascending, the rock-climbing Hydromantes's tail props up the rear of the body, while one hind foot moves forward and then swings to the other side to provide support as the other hind foot advances.

In larvae and aquatic salamanders, the tail is laterally flattened, has dorsal and ventral fins, and undulates from side to side to propel the animal through the water.

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منذ 1 شهور نشر في ٢٠٢٦/٠٥/١١ م

Climbing species have elongated, square-tipped toes, while rock-dwellers have larger feet with short, blunt toes. The tree-climbing salamander (Bolitoglossa sp.) has plate-like webbed feet which adhere to smooth surfaces by suction, while the rock-climbing Hydromantes species from California have feet with fleshy webs and short digits and use their tails as an extra limb.

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منذ 1 شهور نشر في ٢٠٢٦/٠٥/٠٨ م

Some aquatic species, such as sirens and amphiumas, have reduced or absent hind limbs, giving them an eel-like appearance, but in most species, the front and rear limbs are about the same length and project sideward, barely raising the trunk off the ground. The feet are broad with short digits, usually four on the front feet and five on the rear. Salamanders do not have claws, and the shape of the foot varies according to the animal's habitat.

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منذ 1 شهور نشر في ٢٠٢٦/٠٥/٠٧ م

An adult salamander generally resembles a small lizard, having a basal tetrapod body form with a cylindrical trunk, four limbs, and a long tail. Except in the family Salamandridae, the head, body, and tail have a number of vertical depressions in the surface which run from the mid-dorsal region to the ventral area and are known as costal grooves. Their function seems to be to help keep the skin moist by channeling water over the surface of the body.

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منذ 1 شهور نشر في ٢٠٢٦/٠٥/٠٦ م

Salamanders range in size from the minute salamanders, with a total length of 27 mm (1+1⁄8 in), including the tail, to the Chinese giant salamander which reaches 1.8 m (6 ft) and weighs up to 65 kg (145 lb). All the largest species are found in the four families giant salamanders, sirens, Congo eels and Proteidae, which are all aquatic and obligate paedomorphs.

Some of the largest terrestrial salamanders, which go through full metamorphosis, belong to the family of Pacific giant…
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