Echis (common names: saw-scaled viper, carpet viper) is known as a genus of venomous viper and is mostly seen in the dry region of Africa, Sri Lanka, the Middle East, Pakistan, and India.
They have been known to have a distinctive threat display, by rubbing some area of their body together to create a ‘’sizzling’’ warning sound. The name Echis in Latin transliteration of the Greek word means ‘’viper’’(ἔχις).
Their common names are ‘’saw-scaled viper or carpet viper’’, and they are part of the snake species responsible for most of the snakebite cases and death in the world. There are only twelve known species of the genus Echis.
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|Saw-scaled viper (E. carinatus)||Southeastern Arabian Peninsula (Masirah, Oman, and eastern UAE), Iraq, southwestern Iran, Uzbekistan, Afghanistan, Turkmenistan, Tajikistan, India, Pakistan, Sri Lanka and Bangladesh.|
|Painted carpet viper (||Southeastern Egypt east of the Nile, Sinai, Jordan, Israel, the Arabian Peninsula in Saudi Arabia, Oman, and Yemen.|
|Hughes’ carpet viper (||Somalia|
|Jogers’ carpet viper (E. jogeri)||Central and western Mali|
|White-bellied carpet viper (E. leucogaster)||Northwest and west Africa: extreme southern Morocco, Algeria (Ahaggar), Western Sahara, the southern region of Mauritania, northern Guinea, Senegal, central Mali, western Niger, Burkina Faso, and northern Nigeria.|
|Big-headed carpet viper (E. megalocephalus)||Red Sea island between Eritrea and Yemen|
|Ocellated carpet viper or West African carpet viper (E. ocellatus)||Northwest Africa: Senegal, Mauritania, Guinea, Mali, Ivory Coast, Ghana, Burkina Faso, Togo, southern Niger, Benin, Nigeria, southern Chad, and northern Cameroon.|
|Oman saw-scaled viper (E. omanensis)||Eastern Oman and the United Arab Emirates.|
|Northeast African carpet viper (E. pyramidum)||Northeastern Africa: central Sudan and northern Egypt, Ethiopia, Eritrea, Somalia, and northern Kenya; South Yemen (Hadhramaut), Yemen, and Oman (Dhofar); disjunct populations in the northern regions of Tunisia, Libya, and Algeria.|
Saw-scaled vipers or carpet vipers are partially small snakes, the largest species (E. leucogaster, E. pyramidum) always below 35 in (90 cm) in length, and the smallest (E. hughesi, E. jogeri) being around 12 in (30 cm).
The head is relatively small and short, pear-shaped, distinct from the head, and wide. The snout is rounded and short, while the eyes are large and the body is a little bit slender and cylindrical.
The dorsal scales are usually keeled. However, the scales on the lower flank, which sticks out at an angle of 45° and have a central ridge or keel, that is pointy.
The tail appears short, and the subcaudals are single. A saw-scaled viper of the genus Echis may be recognized as the fiery flying serpent in the bible.
Species of this genus are mostly seen in Pakistan, India (in the rocky region of Maharashtra, Punjab, Rajasthan, Pradesh, and Uttar) and Sri Lanka, areas in the Middle East, and Africa north of the equator.
All species of this genus have a characteristic threat display, and they form a series of parallel, c-shaped coils and rubbing them together to create a sizzling sound.
It is called stridulation. The more they are troubled, the stridulation is likely to become louder and faster. This behaviour has been recorded as a way of limiting water loss.
These snakes are dangerous and will strike when disturbed. When doing so, they may become overbalance and move toward their aggressor (an unusual behaviour for snakes).
Not much is known about the diet of some Echis snake species. For some, their diet is known to be extremely varied, such as solifugids, toads, locusts, beetles, worms, frogs, centipedes, scorpions, spiders, slugs, reptiles (including other snakes) birds, and small mammals.
Almost all Echis snake species, those seen in Africa, are all oviparous, while others, seen in India, are viviparous.
The snake venom of the Echis species contains four kinds of toxins: cardiotoxin, hemotoxin, cytotoxin, and neurotoxin. They live in locations with low modern medical facilities. Victims are bitten after dark when these snakes are active.
All these species have venom that contains items that can cause a consumption defibrination and coagulopathy, which may take place for days or weeks. This may result in bleeding in any part of the body, including the possibility of an intracranial haemorrhage.
Venom toxins vary among different species, individual specimens, sexes, geographic locations, and methods of injection (subcutaneous, intravenous, or intramuscular).
Consequently, the LD50 value of Echis venom differs significantly in mice, the intravenous LD50 varies from 24.1 mg/kg (Christensen, 1955) to 0.44 – 0.48 mg/kg (Cloudsley-Thompson, 1988) to 2.3 mg/kg (U.S. Navy, 1991). Venoms from females are two times toxic than that of males.