Rufous beaked snake
Description:
The rufous beaked snake is large and stout, with males reaching a maximum length of 1.1 m (3.6 ft) and females reaching 1.07 m (3.5 ft). It has a shortened skull, as with all beaked snakes, giving it a clear distinction between its head and body, as well as a dark brown eye stripe running down the side of its head.[6] Its eyes are large with round pupils. While its back tends to be yellowish-brown to reddish-brown, its belly is cream or yellowish-white.
Geographic range:
The rufous beaked snake's range includes north Botswana, north Zimbabwe, Mozambique, Tanzania, and Sudan.
Biology:
Diurnal animals, rufous beaked snakes hunt small animals, including other snakes, but stay in burrows during the hottest part of the day. In the summer, females lay eight to 17 cylindrical eggs with dimensions of about 36 mm × 21 mm (1.4 in × 0.83 in) over the span of several days.The snake's venom, one of its components of which is a neurotoxin called rufoxin, causes hypotension and circulatory shock in small mammals, but is not dangerous to humans.
Venom:
Although this snake is mildly venomous it poses no danger to man and hardly even attempts to bite.
Farancia is a genus of colubrid snakes. It consists of two species, one commonly referred to as the rainbow snake and the other commonly referred to as the mud snake. They are native to the eastern half of the United States.
Description
Farancia species can grow to a length of 30-54 inches. They are usually uniform dark brown or black with a brightly colored underside that is red or orange. Rainbow snakes exhibit red striping down their back.
Behaviour
The snakes of this genus are typically semi-aquatic. Living in the muddy edges of slow moving, permanent water sources. Their diet consists primarily of amphiumas, eels, and sirens. Breeding occurs in early spring, and eggs are laid in a burrow near the water in early summer. The clutch incubates between 8–12 weeks, and hatches in mid-autumn.
Species
Farancia abacura - Texas, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida, North and South Carolina, Virginia, Tennessee, Missouri, Illinois, and Kentucky.
Eastern Mud Snake, Farancia abacura abacura (Holbrook, 1836)
Western Mud Snake, Farancia abacura reinwardtii (Schlegel, 1837)
Farancia erytrogramma - Louisiana, Mississippi, Alabama, Georgia, Florida, North and South Carolina, Virginia, and Maryland.
Rainbow Snake, Farancia erytrogramma erytrogramma (Palisot de Beauvois, 1802)
Florida Rainbow Snake, Farancia erytrogramma seminola (Neill, 1964)
Geographic range
The mud snake is found primarily in the southeastern United States, in the states of Texas, Arkansas, Oklahoma, Louisiana, Mississippi, Alabama, Georgia, Florida, North and South Carolina, Virginia, Tennessee, Missouri, Illinois, and Kentucky.
Cultural Significance
The mud snake is one of a few animals which may be the origin of the hoop snake myth. J.D. Wilson Writes:
“ Mud snakes are sometimes known as “hoop snakes” because of the myth that they will bite their own tail and roll after people.[1] ”
The hoop snake myth has also been attributed to the Coachwhip snake.
The Rosy Boa (Lichanura trivirgata) is a snake of the Boidae family, one of only two members of that family native to the United States. The other is the Rubber Boa (C. bottae). Rosy Boas are native to the American Southwest, and Baja and Sonora Mexico.
These small attractive snakes attain a length of 39 in (1 m) (though some specimens from the coast of California reach 4 feet) and a large adult has a body width about the diameter of a golf ball. Coloration in Rosy Boas is highly variable. The common name is derived from the rosy or salmon coloration that is common on the belly of Rosy Boas originating from coastal southern California and Baja Mexico. Most Boas do not have this ventral coloration but instead have a series of dark to orange spots on a light-colored background.
Almost all Rosy Boas have at least some trace of three longitudinal stripes, one down the center of the back, and two on the lower sides. The appearance of these stripes varies widely from extremely straight and having high contrast with the interspaces to extremely broken with almost no contrast with the interspaces. Stripe colors can be orange, maroon, rust, brown, or black. The interspaces range from shades of light to dark gray, yellow, or tan.
Geographic range
The Rosy Boa is found in the southwestern United States in the states of California and Arizona, and northwestern Mexico in the states of Baja California and Sonora. In California, the Rosy Boa ranges throughout the Colorado and Mojave deserts and also occupies the coastal areas of Los Angeles, Orange, Riverside, and San Diego counties. In Arizona, the Rosy Boa occupies the Mojave desert and the western areas of the Sonoran desert. It is absent from the eastern and northern halves of the state. In Sonora, the Rosy Boa ranges from the border with the United States south throughout the Sonoran Desert to at least as far south as Ortiz. In Baja California, the Rosy Boa is almost ubiquitous ranging throughout the entire peninsula except in areas of extremely dry or rockless desert.
Rosy Boas spend most of their lives concealed beneath rocks and in crevices to escape the elements and natural predators. Granite outcroppings are the most common geologic association inhabited by the Rosy Boa. Less often they are found in association with volcanic or other rock types. Only in rare places do Rosy Boas inhabit rockless environments. In areas with few rocks Rosy Boas will use rodent burrows for concealment.
Rosy Boas' activity season follows local weather patterns; however, they are generally dormant during the winter, and active during the spring, summer and fall. Like all snakes, they are dependent on external temperatures to promote such normal bodily functions as digestion and gestation. Throughout most of their range the winter is too cold for these functions and the Rosy Boas go into a dormant state called brumation. The spring is breeding season for Rosy Boas, resulting in their highest rate of activity. Most Rosy Boas are encountered in spring as they leave the security of their rock piles and crevices to seek mates. Another reason Rosy Boas may be active on the surface of the ground is to find prey or new territory.
The surface activity of Rosy Boas can take place during any hour of the day, but during hot weather they are primarily nocturnal. In the spring, they are often abroad in the afternoon and early evening. In the late spring and summer, this activity period switches to from dusk to late into the night. Because most populations of Rosy Boas live in exceedingly dry habitats, their activity is often highly moisture dependent. During dry periods they remain deep underground to assist in remaining hydrated. Recent rainfall often results in a flurry of surface activity.
These snakes forage mainly for small mammals but have occasionally been known to take other prey items such as birds and lizards. Pack rats, baby rabbits, deer mice, and kangaroo rats make up a large portion of their diet. Rosy Boas are one of the slowest-moving species of snake in the world. They are unable to pursue prey and must either wait in ambush or stalk their meals. When a meal is within reach, usually a few inches, a Rosy Boa will strike with surprising speed and accuracy. Prey is secured with tiny rows of needle-sharp teeth, then suffocated through constriction.
Rosy Boas are extremely docile when encountered by humans. When disturbed they usually roll into a compact ball with the head in the center.[1] The species is not prone to bite in defense, and when human bites have occurred they have usually been the result of a feeding response with a captive animal. All Rosy Boa bites are nonvenomous. Their extreme docility and their attractive coloration have made Rosy Boas very popular with herpetoculturists.
Rosy Boas bear live young, about six in a brood. The newborns are about 30 cm (12 in.) in length.
In captivity
Their generally docile temperament, ease of care, and small size makes the Rosy Boa an ideal choice for a pet snake (or first boa). They are frequently captive bred, and readily feed on commercially available mice. Many color variations are available, including albinos as well as the many different subspecies that come in dozens of variations. With other species, such as corn snakes and ball pythons, dominating the majority of the market, the popularity of Rosy Boas hasn't been as high as the other more popular species.
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| black mamba |
The black mamba (Dendroaspis polylepis) is the longest venomous snake in Africa, averaging around 2.5 meters (8.2 ft), and sometimes growing up to 4.3 meters (14 ft). Its name is derived from the black colouration inside the mouth rather than the actual colour of the skin which varies from dull yellowish-green to a gun-metal grey. It is the fastest snake in the world, capable of moving at 4.32 to 5.4 metres per second (16–20 km/h, 10–12 mph).
Description
The black mamba's back skin colour is olive, brownish, gray, or sometimes khaki.[5] The adult snake's length is on average 2.5 meters (8.2 ft),[1] but some specimens have reached lengths of 4.3 to 4.5 meters (14 to 15 ft).[5] Black mambas weigh about 1.6 kilograms (3.5 lb).[1] on average. The species is the second longest venomous snake in the world, exceeded in length only by the king cobra.[5] The snake has an average life span of 11 years in the wild.[1]
Habitat
The black mamba has adapted to a variety of climates ranging from savanna, woodlands, rocky slopes, dense forests and even humid swamps.[6] The grassland and savanna woodland/shrubs that extend through central, eastern and southern Africa are the black mamba's typical habitat.[6] The black mamba prefers more arid environments such as light woodland, rocky outcrops, and semi-arid dry bush country.
Behaviour
The black mamba uses its speed to escape threats, not to hunt prey.[1] It is known to be capable of reaching speeds of around 20 kilometers per hour (12 mph), traveling with up to a third of its body raised off the ground.[1] Over long distances the black mamba can travel 11 to 19 kilometers per hour (6.8 to 12 mph), but in short bursts it can reach a speed of 16 to 20 kilometers per hour (9.9 to 12 mph),or even 23 kilometers per hour (14 mph) [8] making it the fastest land snake.[9] It is shy and secretive; it always seeks to escape when a confrontation occurs.[1] If a black mamba is cornered it mimics a cobra by spreading a neck-flap, exposing its black mouth, and hissing.[1] If this endeavor to scare away the attacker fails, the black mamba may strike repeatedly.[1] The black mamba is a diurnal snake. Although its scientific name seems to be indicative of tree climbing, the black mamba is rarely an arboreal snake.[9] These snakes retreat when threatened by predators.
Venom
The venom of the black mamba consists mainly of potent neurotoxins[10]. With a LD50 of 0.25 mg/kg—0.32 mg/kg, the black mamba's venom is virulently toxic.[11] Some of the components of the venom have a much more toxic LD50 value than the venom as a whole, for example α-dendrotoxin (or "Toxin 1") and γ-dendrotoxin (or "Toxin 7") had subcutaneous LD50 values of 0.09 µg and 0.12 µg per gram of white mice, respectively.[12] Although only 10 to 15 mg[13] is deadly to a human adult, its bite delivers about 100–120 mg of venom on average[13], but they can deliver up to 400 mg of venom in a single bite[13]. It is reported that before the antivenom was widely available, the mortality rate from a bite was 100%.[14][15][16][17][1][18] Black mamba bites can potentially kill a human within 20 minutes or less[19][20][13][12] depending on the nature of the bite and the area bitten, but death usually occurs after 30–60 minutes on average, sometimes even taking up to three hours. British wildlife enthusiast Nathan Layton was bitten near Hoedspruit by a juvenile black mamba and died less than 30 minutes after being bitten.[21] The fatality duration and rate depend on various factors, such as the health, size, age, psychological state of the human, the penetration of one or both fangs from the snake, amount of venom injected, location of the bite, and proximity to major blood vessels.[1] The health of the snake and the interval since it last used its venom mechanism is also important. Presently, there is a polyvalent antivenom produced by SAIMR (South African Institute for Medical Research) to treat all black mamba bites from different localities.[18]
If bitten, common symptoms for which to watch are rapid onset of dizziness, coughing or difficulty breathing, and erratic heartbeat.[18] In extreme cases, when the victim has received a large amount of venom, death can result within minutes[1] from respiratory or cardiac arrest.[18] This is especially true if the victim is bitten in the face or chest area, as a black mamba can rear up around one-third of its body from the ground which puts it at about four feet high. When warding off a threat, the black mamba delivers multiple strikes, injecting large amounts of virulently toxic venom with each strike, often landing bites on the body or head, unlike other snakes. Also, the black mamba's venom has been known to cause paralysis.[18] Death is due to suffocation resulting from paralysis of the respiratory muscles.[18]
Many herpetologists, including South African-born herpetologist Austin Stevens, regard the black mamba as one of, if not the most dangerous and feared snakes in the world due to various factors including the toxicity and high yield of its venom, its high level of aggression, its speed, agility, size, and other factors.[22][12] Nevertheless, attacks on humans by black mambas are rare, as the snakes usually avoid confrontation with humans and their occurrence in highly-populated areas is not very common compared with some other species.
Toxin
Mamba venom is made up mostly of dendrotoxins (dendrotoxin-k - "Toxin K"[23], dendrotoxin-1 - "Toxin 1"[24], dendrotoxin-3 - "Toxin 3"[25], dendrotoxin-7 - "Toxin 7"[25]), and calciseptine[26]. The dendrotoxins disrupt the exogenous process of muscle contraction by means of the sodium potassium pump. Toxin K is a selective blocker of voltage-gated potassium channels[27], Toxin 1 inhibits the K+ channels at the pre and post-synaptic level in the intestinal smooth muscle. It also inhibits Ca2+-sensitive K+ channels from rat skeletal muscle‚ incorporated into planar bilayers (Kd = 90 nM in 50 mM KCl)[28], Toxin 3 inhibits M4 receptors, while Toxin 7 inhibits M1 receptors.[25] The calciseptine is a 60 amino acid peptide which acts as a smooth muscle relaxant and an inhibitor of cardiac contractions. It blocks K+ induced contraction in aortic smooth muscle and it blocks spontaneous contraction of uterine muscle and portal vein.[29][13] The venom is highly specific and virulently toxic. In an experiment, the death time of a mouse after subcutaneous injection of some toxins studied is around 7 minutes. However, a black mamba venom can kill a mouse after 4.5 minutes.[12]
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| black mamba attacking |
Venom:
