Which snakes constrict

But then again, they don't need to be. But even this light pressure, when applied to a rat's torso, makes its system goes haywire, the team discovered. Once blood flow ceases, organs with high metabolic rates—such as the brain, the liver, and the heart itself—begin to shut down. Doctors call this ischemia.

The team theorizes that killing by circulatory arrest has given all constricting snakes—which includes pythons and anacondas —an evolutionary advantage. The quicker the snakes can disable their prey, the lower the chance the predator will get hurt in the process. Think about other animals living alongside boa constrictors in tropical rain forests , says Rosolie: They have teeth, hooves, and claws capable of kicking and ripping.

But a snake just has a mouth—making it extremely vulnerable. Watch a video of an anaconda taking down its prey. For instance, there's evidence that boa constrictors have a tougher time killing ectotherms, animals such as lizards and snakes that rely on external heat to regulate their body temperatures. During a recent expedition to Honduras , for instance, Boback and several other scientists observed a boa constrictor attacking a spinytail iguana. After the snake constricted its prey for an hour, the team collected both animals—assuming the iguana was dead—and went to bed.

In the morning, they were surprised to discover the animals at either end of the observation tank, with the iguana alive and well. Follow Jason Bittel on Twitter and Facebook. All rights reserved. Blood Pythons python curtis live in the forest regions of Southeast Asia. They are heavily built, meaning they are fairly wide for their length.

Their tails are short, while their bodies are thick compared to other snakes of the Python family. Color patterns consist of beige, tan or grayish-brown ground color overlaid with blotches that are brick- to blood-red in color. These snakes are killed for their skin. Roughly , blood pythons are harvested every year for their scales.

They are also kept as exotic pets but are aggressive compared to the docile ball python. By marcodede, CC, via Wikimedia. Boa constrictors come in a variety of colors. Generally, they are a brown, grey, or cream color with red and brown patterns.

These patterns become more pronounced near the tail, as in the case of the red-tailed boa. The coloring is an effective camouflage in the jungles and forests of South and Central America, where this species is most commonly found.

These snakes prefer the rainforest because of the humidity but can survive in near-desert climates if necessary. By Ltshears, CC, via Wikimedia. Adapted to burrowing, the Calabar python's body is cylindrical with a blunt head and equally blunt tail. The head is covered with enlarged shields used for protection and for burrowing into the ground.

The shape of the tail closely resembles that of the head, which is most likely used to confuse predators. This snake lives in the moist rainforests of west and central Africa, but can be found as far east as Lake Kivu. CC, via Wikimedia. Carpet pythons are found mostly in Australia, Indonesia, and New Guinea. Like Ball Pythons, this snake is bred into many different colored morphs. There is no one distinct color for this species. These snakes lay eggs and the mother snake coils around her eggs until they hatch, but after the eggs hatch, the mother snake does not care for her young.

Carpet pythons are usually nocturnal but often warm themselves in the sun. Emerald Tree Boas are rarely seen on the ground. These snakes coil themselves around tree branches waiting for prey to get close enough.

They have a slower metabolism than other snakes so they can go months without eating. These snakes live in the rainforests of South America. They have highly developed front teeth that are proportionately larger than those of any other nonvenomous snakes. Females give birth to live young, producing an average of between 6 and 14 babies at a time, sometimes even more.

Found in the Amazon rainforests of South America, the Garden Tree Boa is a beautiful, nonvenomous snake that comes in a variety of bright colors. Some are totally patternless, while others may be speckled, banded, or saddled with rhomboid or chevron shapes. In many cases I made assumptions based on generalizations about the biology of groups of snakes—for instance, I assumed that all scolecophidians use neither constriction nor venom, that all vipers use venom, and so forth.

But many dipsadine and colubrine colubrids, and many lamprophiids have not been directly studied, and I could find no reports in the literature about their feeding habits. In some cases we don't even know what they eat, and ecological diversity in these groups is very high, such that there are few consistent patterns that I could use to infer prey subjugation mode for these species. Teach yourself about obscure snakes and help fill in the blanks! The most recent similar review was done by Harry Greene in , in which he revised earlier hypotheses he put forth with Gordon Burghardt in the journal Science 16 years before.

We now know a lot more about the snake family tree than we did in , particularly the fine details of relationships within the Caenophidia. Overall, the basic pattern has held up rather well—constriction evolved first in basal alethinophidians during the late Cretaceous, accompanying or preceding most other evolutionary innovations that permit snakes to consume large prey, such as kinetic skulls. Greene pointed out that this was before the origin of rodents, often mentioned as potentially relevant to the evolution of snake prey-killing behaviors.

Constriction was then lost at least twice—once in uropeltids which feed underground on earthworms, although I'm not actually aware of any detailed observations of uropeltid feeding behavior and at least once in basal colubroids, where it might have been at first replaced by venom.

Venom was then subsequently lost in numerous caenophidian lineages, replaced by re-evolution of constriction in some or by other specializations tooth diastemata for holding skinks , egg-eating in others, and in some caenophidian lineages snakes use both as appropriate, sometimes together or they may elect to use neither even if both are available. This could be one reason why venom as an evolutionary innovation led to a more speciose radiation of snakes; it's also more susceptible to evolutionary arms races, because prey can evolve resistance to certain venom compounds, but not to constriction.

Specialization for constriction is more than just behavior— constricting species also have more vertebrae per unit length than non-constricting species. And there are costs to both, which must be outweighed by the benefits of that defining snake trait: being able to consume prey almost as large, and sometimes much larger, than yourself! Thanks to Karen Morris for asking me this question, and to Alpsdake and Danny Davies for the use of their photos.

For a full list of all the references I consulted in preparing this post, click here. Bealor, M. Miller, A. The evolution of the stimulus control of constricting behaviour: inferences from North American gartersnakes Thamnophis. Gans, C. Aspects of the biology of uropeltid snakes. Pages in A. Bellairs and C. Cox, editors. Morphology and Biology of Reptiles. Linnean Society Symposium Series No. Academic Press, London.

The feeding behavior of the snail-eating snake Pareas carinatus Wagler Squamata: Colubridae. Greene, H. Homology and behavioral repertoires. Pages in B. Hall, editor. Scott Boback from Dickinson College has the answer. Through its thick coils, a boa can sense the tiny heartbeats of its prey. When the heart stops, the snake starts to relax.

It would be virtually impossible to measure the heartbeat of a live rat while it was being crushed by a snake, so Boback opted for a macabre alternative. Boback clearly showed that boas finely adjust their coils to the beats of their prey. If the artificial hearts were beating, the boas constricted the rats for twice as long and with twice as much pressure as when the hearts were still.

And all the while, they kept on tightening, bit by bit. If Boback stopped the hearts after 10 minutes, the pythons stopped constricting a few minutes later. They had never killed a victim with an actual heartbeat before, but they responded to the artificial beats in the same way as the wild snakes.

They did, however, use less pressure than the wild ones. Squeezing the breath out of an animal takes a lot of energy. It would seem to make sense for the snake to precisely detect when its prey has breathed its last.