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Naja melanoleucaBlack and White Cobra

By Holly Fitch

Geographic Range

The forest cobra can be found in forests and and shrublands throughout most of sub-Saharan Africa. Countries in which it occurs include: Sierra Leone, Liberia, Ghana, Togo, Benin, Nigeria, Cameroon, Gabon, Kenya, Uganda, Rwanda, Burundi, Cote d’Ivoire, Mali, Senegal, Guinea, the Republic of Congo, Angola, and the Central African Republic. It is found in only small portions of South Africa, but does occur in southern Mozambique and eastern Zimbabwe. (Marais, 2004; Sprawls and Branch, 1995)

Habitat

Naja melanoleuca is the only African cobra that lives in high altitude forest, residing in a wide range of altitudes from sea level to 2800 m. Forest cobras are highly adaptable snakes, and its habitat varies depending on which part of its African range it is living in. In southern Africa, N. melanoleuca is sometimes found in savannah and grassland regions. In its western range, N. melanoleuca can be found in tropical and subtropical forests, savannahs, grasslands, and mangroves. In Zimbabwe, N. melanoleuca occurs in both low and high-altitude forests, woodlands, thickets, and grasslands.

Forest cobras are frequently found near water, mainly rivers or streams, particularly in otherwise dry habitats such as savannas and grasslands. The snake can also live around human developments, and is encountered in the trees of fruit plantations.

Due to increasing human development, much of the forest habitat of N. melanoleuca is being lost and some have begun to live in urban areas due to this habitat loss. (Luiselli, et al., 2002; Mattison, 2007; O'Shea, 2005; Sprawls and Branch, 1995)

  • Range elevation
    0 to 2800 m
    0.00 to 9186.35 ft

Physical Description

The forest cobra is Africa’s largest cobra species, with an average length of 1.4 to 2.2 m and a maximum recorded length of 2.7 m. Males and females grow to similar sizes, there is no sexual dimorphism in the species. Forest Cobras are thick-bodied, cylindrical snakes with a tapering tail. Their head is fairly large with black and white markings on the side which look like black and white bars on the jaws. Like all cobra species, N. melanoleuca has long cervical ribs which allow it to expand the tissue around its neck, forming a wedge-shaped hood. There are several color phases depending on the geographic location of N. melanoleuca: from Sierra Leone east to Kenya, and then south to Angola, they have a glossy black color with a cream or white chin, throat and belly. In the west African savannah, the color pattern consists of black and yellow bands with a black tail and yellow lips, throat, and chin. Within the eastern coastal plain, they are brown or blackish-brown with a cream or yellow belly. Melanistic forest cobras have also been observed. Naja melanoleuca has 19 to 21 dorsal scales, 201 to 214 ventral, 63 to 72 paired subcaudals, 1 anal plate, 7 to 8 upper labials, 1 to 2 preoculars, 2 to 3 postoculars, 8 lower labials, and variable temporal scales. (Marais, 2004; Shine, et al., 2006; Sprawls and Branch, 1995)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    2000 to 3600 g
    70.48 to 126.87 oz
  • Average mass
    2700 g
    95.15 oz
  • Range length
    1.4 to 2.7 m
    4.59 to 8.86 ft
  • Average length
    2.2 m
    7.22 ft

Development

Naja melanoleuca is an oviparous species. Neonates are born completely independent, and are able to hunt on their own at birth as their venom gland is fully developed. The neonates do have a store of energy from the absorption of the egg yolk, however, and are able to sustain themselves for some time. Neonate N. melanoleuca have their first shed within seven to ten days after hatching. They are an average of 22 to 25 cm long and an average of 22.5 grams at hatching. Growth is rapid until sexual maturity (2 to 4 years), after which it slows significantly. Naja melanoleuca follows a pattern of determinate growth, reaching a maximum length of 2.7 meters. (Marais, 2004; Tryon, 1979; Zug and Ernst, 2004)

Reproduction

Forest cobras are a polygynandrous species, as both the male and the female may pair with multiple mates. Male-male combat has been observed in N. melanoleuca, with the two snakes coiling around each other lengthwise, wrestling and biting each other until a winner emerges. Pheromones are used for mate attraction and detection. Male forest cobras always initiate courtship, which may take several hours before copulation occurs. The pair will coil together, and when the female uncoils herself the male will advance towards her while bobbing his head and tongue flicking. The male will then align his cloaca with the female's and will move his tail back and forth until the female is receptive, upon which she will raise her tail to allow the male to copulate. During copulation, which can take over an hour, both sexes will periodically head bob. (Marais, 2004; Shine, et al., 2006; Tryon, 1979)

Naja melanoleuca breeds seasonally from October to February. (Sprawls and Branch, 1995; Tryon, 1979)

  • Breeding interval
    The forest cobra breeds once yearly.
  • Breeding season
    October-February
  • Range number of offspring
    15 to 26
  • Average number of offspring
    20
  • Range gestation period
    60 to 80 days
  • Average time to independence
    0 minutes
  • Average age at sexual or reproductive maturity (female)
    4 years
  • Average age at sexual or reproductive maturity (male)
    2 years

Naja melanoleuca females will coil around and protect their eggs until the neonates emerge. The neonates are born completely independent and there is no further parental investment involved. (Tryon, 1979)

Lifespan/Longevity

The forest cobra once held the record for longevity in captivity with a specimen that lived 28 years. Like most other cobra species, N. melanoleuca has an average lifespan of about 20 years. Current record in captivity is 35 year, but more common range in captivity is 15-30 years, averaging 18. (Sprawls and Branch, 1995)

  • Average lifespan
    Status: wild
    20 years
  • Range lifespan
    Status: captivity
    35 (high) years
  • Typical lifespan
    Status: captivity
    15 to 30 years
  • Average lifespan
    Status: captivity
    18 years

Behavior

The forest cobra is a quick and agile terrestrial snake that is also inclined to climb in trees of 10 meters and higher. Within some of its geographic range, it swims quite often and has been known to feed on fish, so it can be regarded as semi-aquatic. Forest cobras are diurnal in uninhabited areas and nocturnal in urban zones around human activity. When inactive, N. melanoleuca takes cover in brush piles, holes, hollow logs, or rock clusters. In urban zones, it takes cover in abandoned buildings or trash piles.

When threatened, a forest cobra expands its hood and lifts the front of its body far off of the ground to appear larger. They are able to strike very quickly, with great distance. If the snake feels further threatened after these defensive postures, it will make an effort to bite. For these reasons, N. melanoleuca is considered to be one of the most dangerous snakes in Africa and is regarded as aggressive. (O'Shea, 2005; Sprawls and Branch, 1995)

Communication and Perception

Naja melanoleuca can rely on several methods for perceiving either prey or threats. Eyesight is utilized to detect motion, and N. melanoleuca can be quick to strike in response to sudden movements. The tongue is also used to search for and pick up scent molecules in the air. The molecules are then brought into the mouth and analyzed inside the Jacobson’s organ, which is located at the base of the nasal cavity. Through this process, forest cobras can detect the scent of nearby prey or pheromones secreted by the opposite sex. While snakes lack an external ear, they are able to detect vibrations ranging from 50 to 1000 Hz. When the snake is on the ground, sound waves travel via spinal nerves to the jaw muscle, where it is then transferred to the quadrate bone. The stapes (or columella) then transmits the vibrations to the inner ear. When threatened, the forest cobra will perform a defensive display typical of its genus. It will extend its hood and rear up its body. (Mattison, 1999; Zug and Ernst, 2004)

Food Habits

Adult N. melanoleuca feed on rodents, amphibians, birds and bird eggs, other snakes, and anuran tadpoles. Adults do show some preference towards frogs. Juveniles feed mainly on anuran tadpoles, but will also consume small lizards. Forest cobras in west Africa have also been observed to prey upon mudskippers. (Luiselli, et al., 2002; Shine, et al., 2006; Sprawls and Branch, 1995)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • mammals
  • amphibians
  • reptiles
  • fish
  • eggs

Predation

Naja melanoleuca has many potential predators, and they are the most vulnerable when they are juveniles. The most deadly enemy to forest cobras is the mongoose. There are several species of mongoose within the range of N. melanoleuca, and they are immune to venom. They may also fall prey to other species of snakes, such as the black mamba. Wild pigs have been known to feed on snake eggs, and birds of prey may also eat young specimens. Crocodiles or large monitor lizards are other potential predators.

Humans can also be a major threat to N. melanoleuca. Habitat destruction and loss, automobile fatalities, and the killing of snakes out of fear or ignorance can potentially have a devastating impact on the survival of the species. (Luiselli, et al., 2002; Zug and Ernst, 2004)

Ecosystem Roles

Naja melanoleuca acts as a secondary and tertiary consumer, and are prey to other tertiary consumers and apex predators. Forest cobras help control rodent and amphibian populations. Naja melanoleuca may have acarid, protozoan, nematode, flatworm, or amoebic parasites. (Divers, 2015; Zug and Ernst, 2004)

Commensal/Parasitic Species
  • reptile mite Ophionyssus natricis
  • tapeworms in the genus Spirometra
  • threadworms (genus Strongyloides)
  • hookworms in the genu Kalicephalus
  • Entamoeba invadens
  • Cryptosporidium serpentes

Economic Importance for Humans: Positive

Naja melanoleuca helps control the population of rodents and other small mammals, which may be crop pests and potential vectors of human disease. The venom of N. melanoleuca is used in cancer and protein research. Naja melanoleuca is also kept in captivity. (Zug and Ernst, 2004)

Economic Importance for Humans: Negative

The bite of Naja melanoleuca can be lethal to humans. The species possesses a post-synaptic neurotoxic venom that also contains components that disable the complement system of the immune response. The venom also contains anticoagulant properties and prohibits aggregation of platelets. The venom has a LD50 value of 0.6 mg/kg and the average venom yield is 500 mg. Symptoms may include nausea and vomiting, ptosis, elevated heart rate, respiratory distress, and various neurological effects. Although the venom is quite toxic, human envenomations are rare given the size of the population and wide ditribution of the species. This is believed to be due to the habitat preferences of the species. Statistics show that agricultural and other rural activities greatly increase the probability of being bitten. (Akani, et al., 2013; MacKay, et al., 1969; Osipov, et al., 2005; Shupe, 2013; Sprawls and Branch, 1995)

  • Negative Impacts
  • injures humans

Conservation Status

Naja melanoleuca has not yet been evaluated by the IUCN Red List, and it is does not have a special status in CITES.

Contributors

Holly Fitch (author), Indiana University - Purdue University Fort Wayne, Mark Jordan (editor), Indiana University-Purdue University Fort Wayne, George Hammond (editor), Animal Diversity Web Staff.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
drug

a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

venomous

an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

young precocial

young are relatively well-developed when born

References

Akani, G., N. Ebere, D. Franco, E. Eniang, F. Petrozzi, E. Politano, L. Luiselli. 2013. Correlation between annual activity patterns of venomous snakes and rural people in the Niger Delta, southern Nigeria. Journal of Venomous Animals and Toxins including Tropical Diseases, 19:2: 1-8.

Divers, S. 2015. "Parasitic Diseases of Reptiles" (On-line). The Merck Veterinary Manual. Accessed March 31, 2016 at http://www.merckvetmanual.com/mvm/exotic_and_laboratory_animals/reptiles/parasitic_diseases_of_reptiles.html.

Luiselli, L., F. Angelici, G. Akani. 2002. Comparative feeding strategies and dietary plasticity of the sympatric cobras Naja melanoleuca and Naja nigricollis in three diverging Afrotropical habitats. Canadian Journal of Zoology, 80: 55-63.

MacKay, N., J. Ferguson, G. McNicol. 1969. Effects of three cobra venoms on blood coagulation, platelet aggregation, and fibrinolysis. Journal of Clinical Pathology, 22: 304-311.

Marais, J. 2004. A Complete Guide to the Snakes of Southern Africa. South Africa: Struik Publishers.

Mattison, C. 1999. Snake: The Essential Visual Guide. New York, NY: DK Publishing.

Mattison, C. 2007. The New Encyclopedia of Snakes. New York, NY: Princeton University Press.

O'Shea, M. 2005. Venomous Snakes of the World. Princeton, New Jersey: Princeton University Press.

Osipov, A., D. Mordvintsev, V. Starkov, L. Galebskaya, E. Ryumina, P. Bel'tyukov, L. Kozlov, S. Romanov, Y. Doljansky, V. Tsetlin, Y. Utkin. 2005. Naja melanoleuca cobra venom contains two forms of complement-depleting factor (CVF). Toxicon, 46: 394-403.

Shine, R., W. Branch, J. Webb, P. Harlow, T. Shine, J. Keogh. 2006. Ecology of cobras from southern Africa. Journal of Zoology, 272: 183-193.

Shupe, S. 2013. Venomous Snakes of the World: A Manual for Use by U.S. Amphibious Forces. New York, NY: Skyhorse Publishing.

Sprawls, S., B. Branch. 1995. The Dangerous Snakes of Africa. Sanibel Island, FL: Ralph Curtis Publishing, Inc..

Tryon, B. 1979. Reproduction in captive forest cobras, Naja melanoleuca (Serperntes: Elapidae). Journal of Herpetology, 13, 4: 499-504.

Zug, G., C. Ernst. 2004. Snakes: Smithsonian Answer Book. Washington D.C.: Smithsonian Books.

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