크레스티드게코 Many snakes, lizards, turtles, and crocodilians live in dry areas where water is scarce. Without enough water, cells shrivel and die. Reptiles have evolved a series of adaptations to conserve water.
They have impermeable scaly skin and lay eggs with membranes that prevent dehydration. Their kidneys are also efficient at conserving water.
Thermoregulation
Reptiles are ectothermic animals, meaning that they produce very little metabolic heat and that their internal body temperature depends entirely on the ambient temperatures. Because of this, a wide range of adaptations exist for allowing these vertebrates to live in many different environments and maintain their preferred body temperature.
Some reptiles, like this lizard from the rainforest of Brazil, use behavioral thermoregulation to warm themselves. They lie in the sun to absorb its rays and to heat up by radiation and conduction. In the case of some semi-aquatic species, such as crocodiles and tortoises, and most snakes, they stay wet to warm themselves.
Other reptiles, such as this tuatara from New Zealand, rely on thermal gradients in their natural habitat to achieve their desired body temperature. They seek out a patch of sunlight to which they can get close enough to make full use, or they spend most of the day in their burrows and only venture into the open air at night.
In general, a large proportion of reptiles can be found in the tropical, subtropical, and temperate regions of the world, as these environments have more uniform temperature conditions. Even so, it is 크레스티드게코 still possible that reptiles can be found in the coldest temperate areas. These species can do so by employing a number of methods including behavioural thermoregulation, thermal avoidance, and behavioural hibernation.
Tail Displays
Reptiles (except turtles) have tails that can be used for a variety of purposes. Some display them as a sign of aggression or as a defense mechanism. Many snakes and lizards have developed elaborate bluff displays when threatened. These often involve hissing and feigning death. Hognose snakes, for example, writhe violently and excrete urates and feces when disturbed. The feigning behavior is accompanied by an exaggerated S-coil, loud hissing and false strikes. Other lizards may flatten their bodies, puff out their throats or turn broadside to the enemy to increase their apparent size. The helmeted iguanids of Central America and the chameleons of Africa do all of these.
Some snakes, such as mud and ring neck snakes, have brightly colored undersides that are in conspicuous contrast to their body color. When threatened, they sometimes display their tails by lowering them and exposing the underside. This can divert a predator’s attack from the vulnerable head to the less threatening tail.
Other snakes, such as coral and shield-tailed snakes, have short tails that look similar to their heads. They also exhibit a defensive display by displaying their heads and then coiled tightly with their tails in between their jaws. This can deter a predator by showing the brightly colored underside of the tail and making it harder for the snake to be grabbed in an attempt to strike at its head.
Tail Autonomy
Throughout the lizard family tree, autotomy is one of the most widespread antipredator adaptations. The ability to shed a section of tail helps lizards evade capture by diverting predator attacks toward the tail and away from the head and body.
When a lizard sheds its tail, it will often continue to wiggle to distract the predator and to create the impression of continued struggle. Additionally, the regenerated section of tail may differ morphologically from the original segment due to the fact that it is composed of cartilage rather than bones (as in some salamanders).
A variety of studies have found that shedding a portion of the tail can significantly reduce the probability of predation. Moreover, the ability to shed the tail can even allow some lizards to survive capture when their torso becomes too conspicuous or unappetizing for a predator to take notice of them.
Phylogenetic analyses have shown that caudal autotomy is an ancient reptilian behavior. In fact, it appears to have evolved independently in the eureptilian clades Captorhinidae and Lepidosauria. Studies of the fossils of these lizards have also found that the presence or absence of a regenerated caudal tail can serve as an index of lizard predation. However, more research is needed to understand the evolution of the capacity for caudal autotomy. For example, it would be useful to investigate the number and position of fracture planes within the caudal vertebrae of extinct eureptilian lizards.
Hiding Places
Whether it’s a closet or a pile of clothing, hiding places offer reptiles protection from predators and extreme temperatures. Snakes have a particular affinity for dark, damp, and secluded areas—such as the bottom of your bed or a vent in the corner of your room—and will often hide behind boxes, bags, or piles of clothes if they can go unnoticed for a while, Joshua Paske of Paske Pest Control tells Best Life.
Because they are ectothermic, reptiles must rely on ambient environmental temperatures to regulate their internal body temperature, and they cannot tolerate wide temperatures ranges. They use a variety of physiological adaptations, such as brumation, to cope with the cold and vary their activities during weather variations in order to conserve energy.
Amphibians and reptiles exhibit a huge diversity of behaviors and structural morphologies to help them fight off enemies, reproduce, obtain food, and adapt to their environment. Unfortunately, some of these behaviors can be misinterpreted by pet owners and practitioners as a sign of disease or trauma. This lecture focuses on some of the more common and less well-known behavioral and morphological adaptations that are normal for the chelonia discussed but may be misinterpreted as signs of disease or injury. Moreover, it highlights that these adaptive strategies are increasingly important as habitats continue to shrink in our urban-rural world and climate change threatens reptiles with new barriers to dispersal.