There are about 1275 species of skink lizards and most of them are ground dwellers and are represented throughout the world, especially in Southeast Asia and its associated islands and regions of North America.
Their bodies are typically cylindrical in the cross-section. These species mostly have cone-shaped head and long tapering tails. The prehensile-tailed skinks are the largest and can reach about 76 cm, (30 Inches), but most of the species have an average size of 20 cm, (8 inches).
Some skink species have peculiarities as the limbs in some are absent and they have sunken eardrums. As far as nutrition is concerned, they feed on insects and small invertebrates, while the larger species are herbivores and feed on different kinds of fruits. Some species are oviparous and lay eggs while others are viviparous and give birth to the young ones.
6 Main Categories
- Blue Tongue Skinks
- Schneider’s Skinks
- Blue Tailed Skink
- Red-Eyed Crocodile Skink
- Monkey Tailed Skinks
- Fire Skinks
Morphology of Skinks:
Skinks are usually five white-lined black lizards with a blue or red tail. These spend most of the time around the houses and are the most recognizable reptile species. Skinks are smooth and shiny and are often mistaken for salamanders.
The smooth appearance of skinks is due to the tiny bones present under their skin. The five stripes on the back of the skinks run from the head to the tail. They are called blue-tailed skinks due to the coloration of juvenile bodies. As the skink gets older, the blue color fades away.
The males have a brownish colored body with reddish-orange color jaws during the breeding season.
Keeled skinks are semi-aquatic and are found in Southeast Asia to northern Australia. Sand skinks, also known as sandfish can swim through the sand.
Their sunken lower jaws and scales cover the ear openings and allow them to move through the sand without entering their body. These sand skinks are native to North Africa and Southern Asia.
- Keeled Skinks – Southeast Asia
- Sand Skinks – North Africa
Autotomy in Skinks:
Autotomy or self-amputation is the process in which animals discard, or sacrifice their own appendages. It is the process usually used as a self-defense mechanism to elude the predator or to distract him and allows the animal to escape away from the predator.
Animals have the ability to regenerate the lost body part later on. The five-lined skinks rely on their speed to escape from the predators. They can move quickly with their short legs to escape from predators, due to short legs they often resemble snakes. Sometimes when their speed is not enough to escape from the predator, they use their tails to stay alive.
When it’s important to survive, the bright blue tail of five-lined skinks came off and helps them to survive. The color of the tail intends to distract the predators away from them. There are fracture planes in the vertebrae of the tail that helps to separate the tails and muscle close off the blood supply immediately.
Predators of Skinks
- Other Lizards
Can Skinks Live Without their Tails?
The tail serves as the reservoir to store the fat and if skinks lose the tail close to the winter, they may starve to death before the spring. The tailless skinks appear unattractive and thus fail to breed successfully during the period of regrowth.
Regrowth of the tail takes almost a year and the energy in spending for the regrowth purpose instead of the reproduction process. The regrown tails do not match the original tails and appear darker in color, moreover, the ability of the tail to break off is also sacrificed.
This means any future encounters with the predators will have disastrous results for the skinks. Without the tail, skinks can’t run as fast to escape predators.
The Mechanism of Autotomy:
When lizards or salamanders are caught, the detached tail in the attempt to escape from predators will continue to wriggle. The technical term used for the process of sacrificing the tail is called caudal anatomy.
The breakage of the tail occurs when the tail is grasped with sufficient force. Some animals, e.g. the species of geckos perform true autotomy and throw off the tail when stressed sufficiently as when attacked by the ants.
There are Two Forms in which the Caudal Autotomy Takes Place:
- Intervertebral autotomy
- Intravertebral autotomy
In intervertebral autotomy, the tail breaks off between the vertebrae while in the case of intravertebral autotomy, there are zones of weakness or fracture planes across each vertebra in the mid part of the tail.
In the intravertebral autotomy, the lizard contract the muscles to fracture a vertebra rather than breaking the tail between the two vertebrae. Around the caudal artery, there are sphincter muscles that are contracted and help to minimize the bleeding.
The skin flaps often fold over the wound at the site of autotomy and seal the wound, this helps to minimize the chances of infection at the autotomy site. It is an anti-predatory tactic but has high rates of intraspecific competition and aggression.
One of the costs paid by the skinks when they sacrifice the tail is the immune system. Tail loss weakens their immune system and allows other organisms to have negative impacts on their health and lifespan. The tail plays a major role in locomotion and is too valuable to be dropped haphazardly.
Other behaviors noticed are decreased activity and depleted energy resources. In some lizard species, the tail being the major storage organ for the accumulating reserves when lost and when the threat has passed will be eaten by the lizard to recover the part of the sacrificed supplies.
Regeneration is one of the highest priorities after losing the tail in order to optimize the locomotion performance and to regain reproductive fitness.
In fact, it is rare for any of the lizards to go through life without losing the piece of its tail at least once. Once the tail regrows, the bony vertebrae do not grow back but are replaced with the cartilage.
It’s really fascinating that the tail wiggles violently after shedding off by the lizard, but relative to the tail, the lizard hardly moves. That’s the main point; most predators will definitely be attracted to the wiggling tail giving the lizard a precious escape.
The strategy works for at least some lizards because the studies of gut content of the road-killed snakes revealed that many have a lizard tail in their gut but no lizards. The main cause of the wiggling is that the nerves of the lizard’s body are still firming and communicating with each other. Sometimes, the tail keeps moving for upwards of a half-hour. Such a time span is enough for any prey to escape from the predator.
|Species of Skinks||Lifespan||Largest Length||Price|
|Blue Tongue Skinks||20 Years||24"||$199- $499|
|Schneider's Skinks||20 Years||18"||$ 60|
|Blue Tailed Skinks||8 - 10 Years||5" - 8.5"||$ 14.99|
|Red-Eyed Crocodile Skinks||12 Years||8" - 10"||$ 199|
|Monkey Tailed Skinks||20 Years||32"||$ 799|
Fire SkiRed-Eyed Crocodile Skinks
|12 Years||8" - 10"||$ 188 - $ 279|
The Skink losing its tail is a defense mechanism called Autotomy, where the Skinks body is able to lose its tail to preserve its life if attacked. The Loss of the Tail is not fatal and allows the skink to escape with its life. The tail will regrow and the lost tail will continue to wiggle for up to half an hour. Giving the skink time to escape. Most Skinks in their lifetimes have lost their tails to near escapes.