SALAMANDERS
Salamanders are one of the most amazing creatures I've read about. Their evolution is intruiging from their body structure to their feeding and other activities.
Salamanders are a group of amphibians (i.e they can live and survive on/in both aquatic and terrestrial habitats). Although, some species spend greater time in water and some, on land.
Depending on the species, they possess four limbs at right-angle to their body. The fore-limbs usually have 4 digits and the hind-limbs usually have 5 digits. In few species, the number of digits are lesser. The limbs are usually short and sometimes webbed.
Strangely, members of Sirens have reduced or no hind-limbs leaving them to only two fore-limbs.
Salamanders do not have scale even if they are partly aquatic. They all have skins. Their skin may be moist and smooth, velvety or warty. Depending on the species, their skins appear in different variations of colour in form of striped, dots or patches. However, these bright coloured skins with slimy coating may be filled with toxins warning their predators of their unpalatableness. The slimy coating also make it hard for some predators to grasp them.
Respiration in adults is usually carried out by the gills, lungs and skin. Some species such as Hydromantes are lungless and depend solely on their skin and the tissue lining in their mouth.
Also, Sirens possesses christmas-tree-shaped gills that grow by the head region for respiration in water.
Regenerative abilities
Scientists have spent so much time and money on researches with the aim of achieving this ability. Up till now, no achievement have been made to give man the ability to regenerate.
All salamanders have this rare ability to regenerate their limbs and tail when severed. Unlike lizards that regenerate part of their tail when severed, salamanders regenerate completely. The Axolotl can even regrow some of their damaged organs (of course, this doesn't mean that they are immortal).
According to researches, they are able to regenerate thanks to their immune cells especially the macrophages.
Fastest predator
One of the species of salamanders, the Hydromantes usually referred to as web-toed salamanders have been given the honour of the fastest tongue in the animal kingdom. The shooting and withdrawal of its tongue with is as long as it's body (about 80%) can be achieved in less than the blinking of an eye and can only be seen with a slowing the action 40 times.
References:
https://www.livescience.com/34513-how-salamanders-regenerate-lost-limbs.html
https://en.m.wikipedia.org/wiki/Salamander
https://amp.livescience.com/52627-salamanders.html
https://en.m.wikipedia.org/wiki/Hydromantes
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