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منذ 9 ساعات نشر في ٢٠٢٦/٠٦/٢٥ م

A terrestrial salamander catches its prey by flicking out its sticky tongue in an action that takes less than half a second. In some species, the tongue is attached anteriorly to the floor of the mouth, while in others, it is mounted on a pedicel.

It is rendered sticky by secretions of mucus from glands in its tip and on the roof of the mouth.

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منذ 1 أيام نشر في ٢٠٢٦/٠٦/٢٤ م

When struggling prey is advanced into the salamander's mouth, the teeth tips relax and bend in the same direction, encouraging movement toward the throat, and resisting the prey's escape.

Many salamanders have patches of teeth attached to the vomer and the palatine bones in the roof of the mouth, and these help to retain prey. All types of teeth are resorbed and replaced at intervals throughout the animal's life.

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منذ 2 أيام نشر في ٢٠٢٦/٠٦/٢٣ م

Most species of salamander have small teeth in both their upper and lower jaws. Unlike frogs, even the larvae of salamanders possess these teeth.

Although larval teeth are shaped like pointed cones, the teeth of adults are adapted to enable them to readily grasp prey.

The crown, which has two cusps (bicuspid), is attached to a pedicel by collagenous fibers. The joint formed between the bicuspid and the pedicel is partially flexible, as it can bend inward, but not…
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منذ 3 أيام نشر في ٢٠٢٦/٠٦/٢٢ م

Cannibalism sometimes takes place, especially when resources are short or time is limited. Tiger salamander tadpoles in ephemeral pools sometimes resort to eating each other, and are seemingly able to target unrelated individuals.

Adult blackbelly salamanders (Desmognathus quadramaculatus) prey on adults and young of other species of salamanders, while their larvae sometimes cannibalise smaller larvae.

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منذ 5 أيام نشر في ٢٠٢٦/٠٦/٢٠ م

Salamanders are opportunistic predators. They are generally not restricted to specific foods, but feed on almost any organism of a reasonable size.

Large species such as the Japanese giant salamander (Andrias japonicus) eat crabs, fish, small mammals, amphibians, and aquatic insects.

Smaller dusky salamanders (Desmognathus) in the Appalachian Mountains, their diet includes earthworms, flies, beetles, beetle larvae, leafhoppers, springtails, moths, spiders,…
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منذ 6 أيام نشر في ٢٠٢٦/٠٦/١٩ م

The external gills seen in salamanders differs greatly from that of amphibians with internalized gills. Unlike amphibians with internalized gills which typically rely on the changing of pressures within the buccal and pharyngeal cavities to ensure diffusion of oxygen onto the gill curtain, neotenic salamanders such as Necturus use specified musculature, such as the levatores arcuum, to move external gills to keep the respiratory surfaces constantly in contact with new oxygenated water.

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منذ 1 أسابيع نشر في ٢٠٢٦/٠٦/١٨ م

A dissected view of the levatores arcuum muscles in a Necturus maculosus specimen. These move the external gills, as a means of respiration.
In the Necturus, external gills begin to form as a means of combating hypoxia in the egg as egg yolk is converted into metabolically active tissue.

Molecular changes in the mudpuppy during post-embryonic development primarily due to the thyroid gland prevent the internalization of the external gills as seen in most salamanders that…
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منذ 1 أسابيع نشر في ٢٠٢٦/٠٦/١٧ م

In the amphiumas, metamorphosis is incomplete, and they retain one pair of gill slits as adults, with fully functioning internal lungs.

Some species that lack lungs respire through gills. In most cases, these are external gills, visible as tufts on either side of the head. Some terrestrial salamanders have lungs used in respiration, although these are simple and sac-like, unlike the more complex organs found in mammals. Many species, such as the olm, have both lungs and gills as…
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منذ 1 أسابيع نشر في ٢٠٢٦/٠٦/١٦ م

In the lungless salamanders (family Plethodontidae and the clawed salamanders in the family of Asiatic salamanders), no lungs or gills are present, and gas exchange mostly takes place through the skin, known as cutaneous respiration, supplemented by the tissues lining the mouth. To facilitate this, these salamanders have a dense network of blood vessels just under the skin and in the mouth.

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منذ 1 أسابيع نشر في ٢٠٢٦/٠٦/١٥ م

When present in adult salamanders, lungs vary greatly among different species in size and structure. In aquatic, cold-water species like the torrent salamanders (Rhyacotriton), the lungs are very small with smooth walls, while species living in warm water with little dissolved oxygen, such as the lesser siren (Siren intermedia), have large lungs with convoluted surfaces.

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منذ 2 أسابيع 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 2 أسابيع 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 أسابيع 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 2 أسابيع 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 2 أسابيع 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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Jawad

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منذ 3 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 3 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 4 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 4 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 4 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 1 شهور 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 1 شهور 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 1 شهور 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 1 شهور 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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