Chapter-i origins Why are snakes called reptiles? What is a reptile?
Are snakes protected species in India?
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- Bu səhifədəki naviqasiya:
- How does CITES protect snakes
- Appendix-I Appendix-II Appendix-III
- What are the snake species listed in the Red Data Book of I.U.C.N.
- Species Name Common Name Status Distribution
- Why are there reports of large numbers of pythons being discovered in the parks and woodlands in places like Florida, USA though no pythons occur in the wild in USA
- Is there a ’spitting viper’
- Can snakes predict earthquakes
- Do pythons or other such large snakes eat or attempt to eat humans
- Is there a snake that pecks at the eye
- Are there two-headed snakes
- Do snakes emit a foul odour
- Is a snake whose fangs have been removed safe to be handled
- Why should a snake never be defanged
- Is venom dangerous when swallowed
- Is a snake immune to its own venom or venom of other species
- Is there a relationship between the size of a snake species and the virulence of its venom
- What is the reason for the venom of some snakes to have very high potency
- Are there male snakes which produce the scent of females and, if so, why
Are snakes protected species in India? Yes. Under the Wildlife (Protection) Act, 1972, all snakes along with many other animals come under one or the other of the schedules to the Act. The Act prohibits the killing of any animal listed in these schedules except in defence of oneself or of any other person. The Act also allows the killing of any snake (or any other scheduled animal) when it has becomes dangerous to human life or is so disabled or diseased as to be beyond recovery but this is subject to a permit being obtained from the wildlife authorities. The Act allows a snake (or any other scheduled animal) to be captured only if permitted by the wildlife authorities and only for specified purposes such as education, scientific management, research, for recognized zoos, etc. Violations of these provisions are punishable with imprisonment or fine or both. Similarly, trading in products of scheduled animals, including snake venom and snakeskins, without a licence obtained from the wildlife authorities, is an offence punishable with imprisonment or fine or both.
CITES is the acronym for the Washington Convention on International Trade in Endangered Species of Wild Fauna and Flora. India is one of the participating countries. The convention came into force in 1975 and is administered by the United Nations. This regulates international trade in fauna and flora (including products thereof) which are listed as needing different degrees of protection and placed accordingly in different appendices. Trade in these is not necessarily prohibited but is governed by a strict procedure of licensing depending on the degree of protection needed. Appendix I lists the most endangered species i.e. those threatened with extinction. International trade in these species is prohibited except for certain non-commercial purposes such as scientific research. Appendix II lists species that, though not now threatened with extinction, may became so unless trade in them is closely controlled. Appendix III lists species are those included at the request of a country that considers cooperation of other countries necessary for their protection. Indian snakes in the Appendices:-
I.U.C.N. (International Union for Conservation of Nature and Natural Resources) publishes a Red Data Book listing the animal taxa belonging to threatened categories – critically endangered, endangered and vulnerable. The criteria for evaluating a taxon for this purpose are detailed in the book. According to the 2009.1 version of the I.U.C.N. Redlist, the following 18 snakes come under these categories (Vulnerable: 7, Endangered: 7, Critically endangered : 4).
None of the Indian species of snakes comes under these categories. The position is, however, different under the Indian Wildlife (Protection) Act 1972 (See Q & A 287).
A term used to refer to the group of three of the four subfamilies of family Viperidae: Viperinae, Causinae and Azemiopinae. Also called ‘pitless vipers’. 14 genera and 85 species, all restricted to the Old World (Asia, Europe and Africa). The true vipers lack the thermo-receptive pits (See Q & A 21) between the nostril and the eye. Only the members of the subfamily Crotalinae, which is outside this group of true vipers, have ‘pits’ and these are found in both the Old World (Asia, Europe, Africa) and the New World (North and South America). Of the 85 species of true vipers, only three occur in India: Saw-scaled viper (Echis carinatus) Russell’s viper (Daboia russelii) Levantine viper (Macrovipera labetina) The first two are commonly found throughout India. The third is uncommon and found in a few localities in Kashmir. One sub species of Echis carinatus – Sochurek’s saw-scaled viper (Echis carinatus sochureki) – found in parts of Northern India (and also in Pakistan, Afghanistan, South and Central Iran, Oman and UAE), is considered by some as deserving the status of a separate species, but there is no finality on this as yet.
Some snake-lovers, mainly in the U.S., as elsewhere, adopt baby pythons brought from other countries as pets little realizing that the cute, adorable creature will one day become a large, unmanageable python. The better-informed of the owners then gift them to a zoo though it is not always that the zoo will accept the gift. The owners who are unable to fund a willing zoo or who are plain irresponsible and will not even try to find a willing zoo will surreptitiously release the pythons into some nearby wild area as in a park. They become a menace to local wild species of fauna and domestic pets, poultry and even little children. This problem has been reported from parts of U.S. like Florida. (U.S. has no wild pythons). Pythons – mostly the Burmese python (Python molurus bivittatus) – are imported illicitly through pet trade channels.
It is generally believed that only some species of cobras can spit venom (See Q & A: 258). But there is atleast one species of viper that has been reported to do so – the Mangshan pit viper (Zhaoermia mangshanensis) found in the Mangshan area in the Hunan province of China. Mark O’Shea (Venomous Snakes of the World, 2005) fears that this snake may be on the verge of extinction. Even though the spitting habit of this snake finds mention in Gumprecht A. et al., Asian Pit Vipers, 2004, and Mark O’Shea, Venomous Snakes of the World, 2005, Chris Mattison (The New Encyclopedia of Snakes, 2007) seems to have some reservations on this.
Reports have appeared in the press occasionally of the queer behaviour of many species of mammals, birds and snakes well ahead of earthquakes even as the humans had no idea of the impending doom. Similar reports had come also after the tsunami of Dec.2004. The earliest such account seems to be of the earthquake in 373 BC which wrecked the port city of Helice. According to the Roman scholar, Pliny the Elder (23-79 AD), one of the signs of a coming earthquake is “the excitation and terror of animals with no apparent reason”. There are accounts of such phenomena down to the present times. Most of the observations, understandably, relate to cats and dogs, farm animals and commonly seen birds. The historian Diodorus Siculus records animals leaving the city of Helice in droves days ahead of the earthquake of 373 BC much to the puzzlement of the human inhabitants. And, in this exodus, he includes snakes also. On 4 February 1975, there was a major earthquake in the Liaoning province of China causing widespread damage and loss of lives. This had been preceded for some two months by the unusual behaviour of many species of animals and birds. It had been reported in this context that “snakes came out of hibernation, crawled from their burrows and froze to death on the snow-covered surface”. Various theories have been advanced to explain this phenomenon but none that will stand scrutiny. There has been no consistent research on this except some attempts by the Chinese State Seismological Bureau from the 1970s and some studies by Rupert Sheldrake and Daniel Jay Brown in California from the 1980s which have not led to any significant findings so far (For more on this subject, see Dogs That Know When Their Owners Are Coming Home and Other Unexplained Powers of Animals by Rupert Sheldrake, 1999, particularly the chapter captioned ‘Forebodings of earthquakes and other disasters’). While attempting to answer a similar question about cats, Desmond Morris gives possible explanations in his Catwatching, 1986 : (i) sensitivity to very minute vibrations of the earth that precede an earthquake which are not apparent to us or .capable of being registered on our instruments, (ii) responsiveness to the sudden increase in static electricity that apparently precedes earthquakes (iii) responsiveness to sudden shifts in the earth’s magnetic field that accompany earthquakes (iv) detection of all three phenomena at the same time. A report from Reuters appeared in the Press in December 2006 on the observations made by the earthquake bureau in Nanning, capital of the Guangki autonomous region in Southern China, about the curious behaviour of snakes before an earthquake. “Of all the creatures on earth, snakes are perhaps the most sensitive to earthquakes”, bureau director Jiang Weisong was quoted as saying. Jiang said snakes could sense an earthquake 120 km away, three to five days before it happens. “Their erratic behaviour would be an indication of the quake to come”. There is need for more study on this subject.
Folklore may say so, but authentic accounts are extremely rare. The chances of a healthy man or woman being caught in a position that facilitates such a process is improbable although someone who is badly injured or resting or sleeping or incapacitated by alcohol might be vulnerable. Further, even though snakes, especially pythons, can swallow very large prey items (see Q & A 148), the broad shoulders of an adult human will pose a problem for the snake. But children are not unlikely victims.
There is a belief in South India and Sri Lanka that the common vine snake or the whip snake (Ahaetulla nasuta) will peck at the eye of the beholder. For this reason, it is called the ‘eye –pecking snake’ (Kankuthi pāmbu) in Tamil and Malayalam. Its name in Sinhalese is ehetulla meaning ‘eye-pecker’ and it is this that is the basis for its generic name in Latin. While many dismiss this as a superstition, published literature has a few anecdotal accounts from well-known herpetologists about a strange behaviour of this snake. When held in front of the face it lunges at the eyes and at no other part of the face. For more on this, see the author’s paper in Cobra Vol.II Issue 1, 2008. For the many special features of the vine snake’s vision, see Q & A 26.
These are freaks and occur rarely. Two-headed snakes—both heads at the same end – have been reported from India in the checkered keelback (Xenochropis piscator), dog-faced water snake (Cerberus rhynchops), common sand boa (Gongylophis conicus), wolf snake (Lycodon aulicus), Indian cobra (Naja naja) and Russell’s viper (Daboia russelii). Such defective individuals do not survive for long. But in rare cases they have survived for fairly long periods in captivity. The red sand boa (Eryx johnii) is sometimes mistakenly believed to have a second head at its tail end. It is its very blunt tail with a rounded tip that is responsible for this misunderstanding. The blunt tail may serve a purpose in fooling a predator into attacking the tail believing it to be the head thus enabling the snake to escape with only minor consequences.
It is a widespread belief that some snakes emit a foul smell. Snakes are normally odourless. But they have special scent glands situated at the base of their tail which exude a musk-like substance at certain times, to attract a mate or, sometimes, as a defence tactic. The smell of this varies from snake to snake and, in some cases, it may be unpleasant (to humans and predators). See also Q & A 95.
No. In snakes, all teeth including fangs, are shed regularly and replaced regularly. This may be in cycles of 10 to 70 days depending on the species and the health of the snake. In a venomous snake, when an active fang gets ripped off either by accident or by human intervention or is shed in course of time, the next most-mature fang will take its place.
Defanging a venomous snake is often resorted to by snake-charmers and others who handle snakes in a mistaken attempt to make them ‘safe’ to handle. This is a cruel practice. The defanging is almost always done in a crude manner causing injury to the snake making it difficult for the snake to eat and also causing infections in the mouth. That apart, since the venom is an enzyme to aid digestion, a defanged snake, even if, being a captive specimen, it does not have to hunt its prey, it will be in distress. In any case, this practice does not help the snake charmer or snake handler since another fang will soon take the place of the lost fang.
Venom is dangerous when it gets into the blood stream. Therefore, if there are no lacerations in the mouth or the digestive tract and no cavities in the teeth, venom can safely be swallowed, but not in very large quantities since, in that case, it is not unlikely that a little of it (but enough to be dangerous) may be absorbed. But, then, why try it at all?
The snake is generally immune to its own venom and of related species. However, a bite from an unrelated species may prove fatal though, sometimes, there could be a partial immunity. The habitually snake-eating king cobra is not safe from the bite of a Russell’s viper. The snake-eating mussarana of Central and S. America (See Q & A 268) is immune to the venom of the central and S. American pit-vipers but not to the venom of the coral snakes. King snakes of America are immune to the venom of rattle snakes on which they prey, but the immunity is not total.
Yes, but, paradoxically, it is in the inverse proportion. In related species of snakes, the general observation is that the larger the species, the less virulent the venom. Conversely, the smaller the species, the more virulent the venom. But, really, this is not surprising since this is Nature’s way of compensating for the smaller quantity of venom in a small snake. Examples : -- The large-sized banded krait (Bungarus fasciatus) and its smaller relative, the common krait (Bungarus caeruleus). -- The large-sized Russell’s viper (Daboia russelii) and its smaller relative, the saw-scaled viper (Echis carinatus). -- The large-sized king cobra (Ophiophagus hannah) and the (somewhat distantly) related Indian cobra (Naja naja).
There could be two reasons for this. Firstly, coevolution. As the prey species, in the course of evolution, develop greater and greater resistance to the snake’s venom, the snake has to develop venom with greater and greater potency. This is a vicious circle and holds good for all venomous snakes. Secondly, the nature of the prey species. Fast-swimming fishes being the prey of sea snakes, it is necessary for sea snakes to quickly kill or incapacitate or the prey may be lost, and for this, very high potency of venom is essential. The two reasons could also interact taking the process forward.
Richard Shine and Robert Mason have given an account of the queer behaviour (no pun intended) of the red-sided garter snake (Thamnophis sirtalis parietalis) in Manitoba, Canada. During the eight-month long severe winter, these snakes in their thousands take shelter in hibernacula (See Q & A 134), sometimes more than 10,000 huddled together in rocky depressions no more than 100 square metre. in size. The mating season starts immediately after the hibernation is over. Males emerge first from the hibernaculum and wait in huge numbers at the exit for the females to appear. As soon as a female emerges, hundreds of males cluster round her in a huge ‘mating ball’ and the ‘mating balls’ move en masse (like ‘live spaghetti’) over rocks and vegetation until the female has mated. Curiously, some ‘mating balls’ contain no females. In 1985, Bob Mason and David crew found that such odd ‘mating balls’ consist of desperate males attempting to mate with certain other males which they seem to mistake for females notwithstanding that they cannot be so mistaken by size or markings. The two scientists discovered that the mix-up happened because the males mistaken for females were exuding what resembled the female pheromones (See Q & A 177). The reasons for some of the males thus mimicking females are not very clear. The two scientists hypothesize that since the females are far fewer in number than males in this species, there is intense competition among the males to secure a female. In this process, some of the males who are not as yet ready for mating try to mislead the other males and lure them away from the females by exuding the female pheromones so that the females will be available to them later on. This phenomenon of male snakes mimicking females has not been noticed in any other species. (Shine, R. & Mason, R. 2001. Serpentine cross dressers, Natural History. 2/01 (12 Sept 09; http://oregonstateedu/~masonr/pdfs/057serpentinecross.pdf).
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