Echis (common names: saw-scaled viper, carpet viper) is 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 display a distinctive threat by rubbing some areas of their body 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 worldwide.
There are only twelve known species of the genus Echis.
Scientific Classification
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Reptilia |
| Order | Squamata |
| Suborder | Serpentes |
| Family | Viperidae |
| Subfamily | Viperinae |
| Genus | Echis |
Species
| Species | Distribution |
| 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 (E. coloratus) | Southeastern Egypt east of the Nile, Sinai, Jordan, Israel, the Arabian Peninsula in Saudi Arabia, Oman, and Yemen. |
Hughes’ carpet viper (E. hughes) | 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. |
Characteristics
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, the eyes are large, and the body is slightly slender and cylindrical.
The dorsal scales are usually keeled. However, the scales on the lower flank stick out at an angle of 45° and have a pointy central ridge or keel.
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.
Distribution
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.
Behavior
All species of this genus have a characteristic threat display, forming 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 more stridulation will become louder and faster. This behavior 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 overbalanced and move toward their aggressor (an unusual behavior for snakes).
Diet
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.
Reproduction
Almost all Echis snake species, those seen in Africa, are oviparous, while others, seen in India, are viviparous.
Venom
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 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 hemorrhage.
Venom toxins vary among species, individual specimens, sexes, geographic locations, and injection methods (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 more toxic than that of males.
