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Tuesday, 19 April 2011

Mulilo, Supposedly an Unsightly Slugly Snake

Raheel Mughal's list of lesser-known African cryptids comes to entry number six, which to me was always a transparently obvious category, although apparently not to Karl Shuker, George Eberhart or the majority of other Cryptozoologists:

"(6) Mulilo: The Mighty Mollusc! The Mulilo is described as a giant slug purported to live in the dense forests of the Congo, Zaire and Zambia. Not much is known about this mighty mollusc except that it is herbivorous, greyish-white to brown in colouration and tends to climb trees albeit at a slow pace. Nevertheless, it could be possible that such a creature does indeed exist. For example, one species of land snail, the Giant African Snail, can grow to be 15 inches (38 cm). So it is not that much of a stretch of the imagine to suggest that other land-dwelling molluscs can grow to be much larger than the Giant African Snail."

To which I replied:

"6) Mulilo is at base probably nothing more (and nothing less) than a melanistic form of Gaboon viper: the size and shape matches otherwise. Gaboon vipers are highly venomous and have enormous fangs, but they are stout and sluggish snakes otherwise."

The first mention of Mulilo that I was aware of was printed in Karl Shuker's 1997 book From Flying Toads to Snakes With Wings, Chapter 18. Therein it was stated that the rainbow in parts of Zaire and Zambia heralds the appearance of the Mulilo, a coal-black poisonous slug almost six feet long and a foot wide, which is caught in spine-lined cages baited with roosters so that its flesh can be used by the natives as fetishes (=material devices containing magical power)
Shuker gives his source as an 1940 article in Empire Review by W. L. Speight

The dimensions are easily recognised as approximating the Gaboon viper, Bitis gabonica, even though slightly exaggerated, and the gaboon viper is easily the ONLY poisonous animal anywhere near those dimensions native to the area. The confusing part is the extremely dark colouration, which is not typical for the species. It is to be understood as a rare and freakish variation wherein all of the colours of a normal viper are darkened to the point of appearing black (or to the point of being described as such by a casual observer)

Here is the information from Wikipedia:

Bitis gabonica
Common names: Gaboon viper, butterfly adder, forest puff adder, swampjack,[2] (more).
Bitis gabonica is a venomous viper species found in the rainforests and savannas of Sub-Saharan Africa.[1] This is not only the largest member of the genus Bitis,[3] but also the world's heaviest viperid[2] and it has the longest fangs (up to 2 inches),and the highest venom yield of any venomous snake.[2] Two subspecies are currently recognized, including the nominate race described here.[4]

DescriptionAdults average 122–152 cm (4 to 5 feet) in length with a maximum of 205 cm (81 in) for a specimen collected in Sierra Leone. The sexes may be distinguished by the length of the tail in relation to the total length of the body: approximately 12% for males and 6% for females. Adults, especially females, are very heavy and stout. One female had the following dimensions:[2]

Total length 174 cm (69 in)
Head width 12 cm (4.7 in)
Girth 37 cm (14.65 in)
Weight (empty stomach) 8.5 kg (19 lbs)

B. gabonica. Note the tiny horns between the nostrils and the two stripes below the eye.In their description of B. gabonica, Spawls et al.. (2004) give an average length of 80–130 cm (32 to 51.5 in), with a maximum size of 175 cm (69.3 in), saying the species may possibly grow larger still. They acknowledge reports of specimens over 6 feet (1.8 m), or even over 2 m (6.5 ft) in length, but claim there is no evidence to support this.[5]

The head is large and triangular, while the neck is greatly narrowed: almost one-third the width of the head.[2] A pair of horns is present between the raised nostrils — tiny in B. g. gabonica, but much larger in B. g. rhinoceros.[5] The eyes are large and moveable,[2] set well forward,[5] and surrounded by 15–21 circumorbital scales.[2] There are 12–16 interocular scales across the top of the head. 4–5 scale rows separate the suboculars and the supralabials. There are 13–18 supralabials and 16–22 sublabials.[2] The fangs may reach a length of 55 millimetres (2.2 in) :[3] the longest of any venomous snake.[2]

Midbody, there are 28–46 dorsal scale rows, all of which are strongly keeled except for the outer rows on each side. The lateral scales are slightly oblique. The ventral scales number 124–140: rarely more than 132 in males, rarely less than 132 in females. There are 17–33 paired subcaudal scales: males have no fewer than 25, females no more than 23. The anal scale is single.[2]

The color pattern consists of a series of pale, sub-rectangular blotches running down the center of the back, interspaced with dark, yellow-edged hourglass markings. The flanks have a series of fawn of brown rhomboidal shapes, with light vertical central bars. The belly is pale with irregular brown or black blotches. The head is white or cream with a fine, dark central line, black spots on the rear corners, and a dark blue-black triangle behind and below each eye.[5] The iris color is cream, yellow-white, orange[5] or silvery.[6]

Common names
Gaboon viper, butterfly adder, forest puff adder, swampjack,[2] Gaboon adder,[3] Gabon viper.[7]

Originally a name given by the Portuguese, Gabon (Gabão) refers to the estuary on which the town of Libreville was built, in Gabon, and to a narrow strip of territory on either bank of this arm of the sea. As of 1909, Gaboon referred to the northern portion of French Congo, south of the Equator and lying between the Atlantic Ocean and 12° east longitude.[8]

Geographic range

Distribution of B. gabonica (in black)[3]This species can be found in Guinea, Ghana, Togo, Nigeria, Cameroon, DR Congo, Central African Republic, southern Sudan, Uganda, Kenya, eastern Tanzania, Zambia, Malawi, eastern Zimbabwe, Mozambique, northeast KwaZulu-Natal Province in South Africa. Mallow et al. (2003) also list Sierra Leone and Liberia in West Africa.[2] The type locality is given as "Gabon" (Africa).[1]

The Gaboon viper is usually found in rainforests and nearby woodlands, mainly at low altitudes,[6] but sometimes as high as 1500 m.[2] Spawls et al. (2004) mention a maximum altitude of 2100 m.[5] According to Broadley and Cook (1975), it is generally found in environments that are parallel to those occupied by its close relative, B. arietans, which is normally found in more open country.[9]

In Tanzania, this species is found in secondary thickets, cashew plantations, and in agricultural land under bushes and in thickets. In Uganda, they are found in forests and nearby grasslands. They also do well in reclaimed forest areas: cacao plantations in West Africa and coffee plantations in East Africa. They have been found in evergreen forests in Zambia. In Zimbabwe, they only occur in areas of high rainfall along the forested escarpment in the east of the country. In general they may also be found in swamps, as well as in still and moving waters. They are commonly found in agricultural areas near forests and on roads at night.[2]

Primarily nocturnal, Gaboon vipers have a reputation for being slow-moving and placid. They usually hunt by ambush, often spending long periods motionless, waiting for suitable prey to happen by. On the other hand, they have been known to hunt actively, mostly during the first six hours of the night. In Kumasi, Ghana, they were regularly killed around some stables in an open area with the forest some 500 meters away — a sign that they were hunting rats in the grassland. They are usually very tolerant snakes, even when handled, and rarely bite or hiss, unlike most vipers. However, bites by bad-tempered individuals do occur.[5]

An ambush predator, its color pattern gives it excellent camouflage. Locomotion is mostly rectilinear, in a sluggish "walking" motion of the ventral scales. They may writhe from side to side when alarmed, but only for short distances.[2] Ditmars (1933) even described them as being capable of sidewinding.[10]

If threatened, they may hiss loudly as a warning, doing so in a deep and steady rhythm, slightly flattening the head at the expiration of each breath.[2][5][10] Despite this, they are unlikely to strike unless severely provoked.[2]

There have been numerous descriptions of their generally unaggressive nature. Sweeney (1961) wrote that they are so docile that they "can be handled as freely as any non-venomous species", although this is absolutely not recommended. In Lane (1963), Ionides explains that he would capture specimens by first touching them lightly on the top of the head with a pair of tongs to test its reaction. Anger was rarely displayed, so the tongs were usually set aside and the snake firmly grasped by the neck with one hand and the body supported with the other as he picked it up and carried it to a box for containment. He said the snakes hardly ever struggled.[2]

Parry (1975) describes how this species has a wider range of eye movement than other snakes. Along a horizontal plane, eye movement can be maintained even if the head is rotated up or down to an angle of up to 45°. If the head is rotated 360°, one eye will tilt up and the other down, depending on the direction of rotation. Also, if one eye looks forwards the other looks back, as if both are connected to a fixed position on an axis between them. In general, the eyes often flick back and forth in a rapid and jerky manner. When asleep, there is no eye movement and the pupils are strongly contracted. The pupils dilate suddenly and eye movement resumes when the animal wakes up.[2]

Because of their large heavyset size, the adults have no trouble eating prey as large as fully-grown rabbits. When prey happens by them, they strike with fast precision and then usually hold onto their prey like a constrictor until the venom takes effect and the prey dies which can take a few minutes depending on the size of the prey. These snakes feed on a variety of birds and mammals, such as doves, many different species of rodents, including field mice and rats, as well as hares and rabbits. There are also reports of more unlikely prey items, such as tree monkeys, the brush-tailed porcupine (Atherurus) and even the small royal antelope (Neotragus).[2]

During peak sexual activity, males engage in combat. This starts with one male rubbing its chin along the back of the other. The second male will then raise its head as high as possible. As they both do the same, the necks intertwine. When the heads are level, they turn towards each other and push. Their bodies intertwine as they switch positions. They become oblivious to everything else, continuing even after they fall off a surface or into water. Sometimes they intertwine and squeeze so tightly that their scales stand out from the pressure. They have also been observed to strike at each other with mouths closed. Occasionally, the combatants will tire and break off the fight by "mutual consent", resting for a while before resuming once more. The event is settled when one of the two succeeds in pushing the other's head to the ground and raising its own by 20–30 cm. In captivity, combat may occur 4–5 times a week until courtship and copulation ends.[2]

Gestation takes about a year, which suggests a breeding cycle of 2–3 years. A 5-year breeding cycle may also be possible. Usually, they give birth in late summer. B. g. gabonica produces 8–43 live young. B. g. rhinoceros may produce as many as 60. However, the actual number of offspring rarely exceeds 24.[2] Neonates are 25–32 cm in length and weigh 25–45 g.[3]


Bites are relatively rare, due to their docile nature and the fact that their range is mainly limited to rainforest areas.[3] Due to their sluggishness and unwillingness to move even when approached, people are often bitten after they accidentally step on them, but even then in some cases they may not bite.[11] However, when a bite does occur it should always be considered a serious medical emergency. Even an average bite from an average sized specimen is potentially fatal.[3] Antivenom should be administered as soon as possible to save the victim's life if not the affected limb.[9]

The snake's hemotoxic venom itself is not considered particularly toxic. In mice, the LD50 is 0.8–5.0 mg/kg IV, 2.0 mg/kg IP and 5.0–6.0 mg/kg SC.[12] However, the venom glands are enormous and produce the largest quantities of any venomous snake. Yield is apparently related to body weight, as opposed to milking interval.[2] Brown (1973) gives a venom yield range of 200–1000 mg (of dried venom),[12] A range of 200–600 mg for specimens 125–155 cm in length has also been reported.[2] Spawls and Branch (1995) state that from 5–7 ml (450–600 mg) of venom may be injected in a single bite.[3]

A study by Marsh and Whaler (1984) reported a maximum yield of 9.7 ml of wet venom, which translated to 2400 mg of dried venom. They attached "alligator" clip electrodes to the angle of the open jaw of anesthetized specimens (length 133–136 cm, girth 23–25 cm, weight 1.3–3.4 kg), yielding 1.3–7.6 ml (mean 4.4 ml) of venom. Two to three electrical bursts of five seconds each were enough to empty the glands. The snakes used for the study were milked 7–11 times over a 12-month period, during which they remained in good health and the potency of their venom remained the same.[2]

Based on how sensitive monkeys were to the venom, Whaler (1971) estimated that 14 mg of venom would be enough to kill a human being: equivalent to 0.06 ml of venom, or 1/50–1/1000 of what can be obtained in a single milking. Marsh and Whaler (1984) wrote that 35 mg (1/30 of the average venom yield) would be enough to kill a man of 70 kilograms (150 lb).[2] Branch (1992) suggested that 90–100 mg would be fatal in humans. Further investigation is needed.

In humans, a bite causes rapid and conspicuous swelling, intense pain, severe shock and local blistering. Other symptoms may include uncoordinated movements, defecation, urination, swelling of the tongue and eyelids, convulsions and unconsciousness.[2] Blistering, bruising and necrosis may be extensive. There may be sudden hypotension, heart damage and dyspnoea.[5] The blood may become incoagulable with internal bleeding that may lead to haematuria and haematemesis.[3][5] Local tissue damage may require surgical excision and possibly amputation.[3] Healing may be slow and fatalities are not uncommon.[5]

Subspecies[4] Taxon author[4] Common name[2] Geographic range[3]
B. g. gabonica (Duméril, Bibron & Duméril, 1854) East African Gaboon viper Central, eastern and southern Africa.
B. g. rhinoceros (Schlegel, 1855) West African Gaboon viper West Africa.

Lenk et al. (1999) discovered considerable differences between the two conventionally recognized subspecies of B. gabonica described above. According to their research, these two subspecies are as different from each other as they are from B. nasicornis. Consequently, Lenk et al. (1999) regard the western form as a separate species, B. rhinoceros.[13]

See also
List of viperine species and subspecies
Viperinae by common name
Viperinae by taxonomic synonyms
1.^ a b c McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
2.^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. 359 pp. ISBN 0-89464-877-2.
3.^ a b c d e f g h i j k Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. ISBN 0-88359-029-8.
4.^ a b c "Bitis gabonica". Integrated Taxonomic Information System. Retrieved 6 August 2006.
5.^ a b c d e f g h i j k Spawls S, Howell K, Drewes R, Ashe J. 2004. A Field Guide To The Reptiles Of East Africa. London: A & C Black Publishers Ltd. 543 pp. ISBN 0-7136-6817-2.
6.^ a b Mehrtens JM. 1987. Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. ISBN 0-8069-6460-X.
7.^ Gotch AF. 1986. Reptiles -- Their Latin Names Explained. Poole, UK: Blandford Press. 176 pp. ISBN 0-7137-1704-1.
8.^ Gaboon at New Advent Catholic Encyclopedia. Accessed 8 July 2007.
9.^ a b Broadley, G.; Cock, E.V. (1975). Snakes of Rhodesia. Longman Africa, Salisbury. OCLC 249318277
10.^ a b Ditmars RL. 1933. Reptiles of the World. The MacMillan Company. Revised Edition. 329 pp. 89 plates.
11.^ Marais J. 2004. A Complete guide to the Snakes of Southern Africa. Struik, Cape Town. 214 pp. ISBN 9781868729326.
12.^ a b Brown JH. 1973. Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. ISBN 0-398-02808-7.
13.^ Venomous Snake Systematics Alert - 1999 Publications at Homepage of Dr. Wolfgang Wüster of the University of Wales, Bangor. Accessed 3 September 2006.
[edit] Further readingBowler JK. 1975. Longevity of reptiles and amphibians in N. American collections as of 1 November 1975. Society for the Study of Amphibians and Reptiles, Miscellaneous Publications, Herpetological Circular, 6:1–32.
Brown JH. 1973. Toxicology and Pharmacology of Venoms from Poisonous Snakes. Published by Charles C. Thomas.
Forbes CD, Turpie AGG, Ferguson JC, McNicol GP, Douglas AS. 1969. Effect of gaboon viper (Bitis gabonica) venom on blood coagulation, platelets, and the fibrinolytic enzyme system. Journal of Clinical Pathology 22:312–316.
Lane, M. 1963. Life with Ionides. London: Hamish-Hamilton. 157 pp.
Lenk P, Herrmann H-W, Joger U, Wink M. 1999. Phylogeny and taxonomic subdivision of Bitis (Reptilia: Viperidae) based on molecular evidence. Kaupia, 8:31–38.
Marsh NE, Whaler BC. 1984. The Gaboon viper (Bitis gabonica) its biology, venom components and toxinology. Toxicon, 22(5):669–94.
Sweeney RCH. 1961. Snakes of Nyasaland. Zomba, Nyasaland: The Nyasaland Society and Nyasaland Government. 74 pp.

External links: Wikimedia Commons has media related to: Bitis gabonica

Bitis gabonica at the Reptile Database. Accessed 2 August 2007.
Keeping Gaboon Vipers at Accessed 2 August 2007.
Video of B. g. gabonica and B. arietans on YouTube. Accessed 9 December 2006.
Video of B. g. gabonica feeding on YouTube. Accessed 8 August 2007.
B. g. gabonica image at Glades Herp. Accessed 9 August 2007


  1. My brother Benny mentions that it is good to add here that some poisonous snakes in the UA like the diamondback rattlesnake or the copperhead can be occasionally much darker so that the "diamondback" pattern does not show and the poisonous snake might superficially resemble a darker nonpoisonous species. For that reason alone it is well to be cautious in approaching unfamiliar snakes.

    Best Wishes, Dale D.

  2. The myth about the "Rainbow Snake" is actually pan-tropical and the myth occurs in South India as well as in Australia. In the remnant religion of the deported African slaves, a Rainbow snake deity remains important in New World "Voodoo" cults.

    Best Wishes, Dale D.


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