게코도마뱀
Reptiles display a wide variety of behaviors and structural morphologies that help them to escape from enemies, reproduce, obtain food, and adapt to their environment. Some of these behaviors are normal and others may be misinterpreted by the amateur hobbyist or the clinician as signs of disease.
게코도마뱀For example, researchers trained one bearded dragon to slide a door open. They then showed the lizard to other lizards and they all slid the door in the same direction that was demonstrated.
Predatory Displays
Many reptiles display a variety of deceptive defensive displays in response to predation. These include bluffing, threat, and fake strikes. The display may also involve a loud hiss. This type of behavior is common in snakes, lizards, and other chelonians. A hognose snake (Heterodon) is well known for its complex death feigning behavior that consists of an exaggerated S-coil, loud hissing, and false striking. This behavior diverts a predator’s attack away from the head to the more vulnerable tail.
Whether the display is honest aposematism or a false warning has never been tested in the wild. In fact, the survival value of deimatic displays is often assumed to depend on generalized predator learning rules, rather than on specific visual characteristics of the defended prey species that are displayed1.
Mountain katydids (Acrieza reticulata) reveal a vivid red-, blue-, and black-banded abdomen when attacked. This is a deimatic display that enables them to warn predators of their poison glands. However, this signal is not effective against naive predators in the laboratory. A new study suggests that the post-attack conspicuous display of the katydid facilitates predators’ associative learning about its non-conspicuous normal look and chemical defenses1. This is consistent with the facilitation hypothesis. However, the results also suggest that the katydid’s post-attack conspicuous display does not protect it from being fatally handled by predators after an initial attack.
Defensive Displays
The rattling of the tail (usually on a rock or piece of wood) is an almost universally recognized display behaviour in both venomous and non-venomous snakes. This is done to send a message of aggression that may deter a predator. Other defensive displays include writhing, regurgitation, emptying of the cloacal glands to release a foul smelling odour/taste and even death displays (best known in Eastern Hognose snakes).
Some reptiles will shed their tail when grabbed by a predator this is called 게코도마뱀 Caudal Autotomy and is a very effective form of defence. They then continue to writhe and vibrate the tail to divert the predators attention away from the vulnerable head/body area and give them time to escape.
A variation on this is seen in some Leopard Geckos where the tail is ‘waved’ to attract the attention of the predator. This works by attracting the eyes and distracting the predator from the body area.
Another common display is gaping threats exhibited by iguanas when threatened or competing for food, perches and basking sites. These are highly aggressive displays that can lead to full bites if the display is not heeded. Similarly monitors and Asian rat snakes flatten the caudal and cranial areas of their neck to increase their size in threat displays. This also reveals bright colours that would normally be concealed and acts as a deterrent to the predator.
Tail Displays
Some reptiles wave their tails to attract the attention of predators. This display is particularly effective for lizards and snakes with striped or zebra-like skin. The display helps to deflect the predator’s attention from the lizard’s head and body, and allows it to observe its surroundings. A recent study on zebra-tailed lizards found that when the lizards were foraging in areas that were populated by many predators they wagged their tails more often than those lizards that foraged in safer spaces.
The writhing behavior of coral snakes (Uropeltidae) and monitor species is a highly effective threat or bluff display that involves the expulsion of cloacal contents, false strikes and a tightly coiled posture. These displays also serve to reveal brightly colored contrasting ventrums to the predator which can startle it.
Another common defensive behavior is gaping threat display in which a lizard’s mouth opens wide and exposes its bright pink oral mucosa to the predator. This display may be accompanied by a low guttural hiss. This is a powerful display of aggression and can lead to full bites and tail lashing if not heeded.
Many lizards and snakes exhibit this display when they are in a territory and attempting to defend it from other members of the same species. The displaying animal will erect crests along the back and neck, puff up the body and emit a long loud hiss from the lungs. Pine snakes (Pythonidae) have evolved a septum in their glottal opening that serves to amplify the sound and enhance the effectiveness of this defense mechanism.
Active Hunting
Several reptile species, particularly snakes and monitor lizards, are able to use stealthy movements to ambush prey. This type of hunting can be difficult for observers to see, but accelerometer data from radio-telemetry tracking devices can reveal the distinctive sequences of movements associated with caching or handling prey. These sequences, for example, include carrying food with forelimbs, digging with a claw or head, tamping with the muzzle to press the food into soil and finally scooping the prey with the head.
In contrast to the ambush foragers, some snakes rely on sedentary, sit-and-wait strategies and use sheltering sites for long periods. Such predators, which include pit vipers and certain smaller lizard species, are known as pursuit hunters, and their low movement rates and home range sizes reflect the need to remain near prey for lengthy durations. It is thought that this behavior evolved around the Tertiary period as a response to ungulate prey’s increasing feeding range in response to climate change.
The specialized movements of pursuit predators, however, are not well suited to conventional home range estimation methods, and minimum convex polygons or kernel density estimators are often used in herpetological spatial ecology studies. Newer movement-based models, such as dynamic Brownian bridge movement models (dBBMMs), may offer a more suitable solution. These models generate probabilistic utilization distributions that provide a more flexible approach to answering space-use questions than MCPs or KDEs, but further research is needed to test this hypothesis.