Boomslang

## About

A cape Boomslang in a tree

The boomslang ***(Dispholidus typus)*** (pronounced BWUM-SLUHNG) is an extremely dangerous species of African tree snake. The name of the boomslang is directly derived from the Afrikaans word for 'tree snake'. Boomslang are a small to medium sized snake species that are considered to possess the most potent venom out of all of the African snake species. Boomslang can come in a wide variety of appearances depending on their sex, age and environment. The species exhibits mild sexual dimorphism, with male boomslang having yellowish-green scales that are extremely vibrant, whereas female individuals have a much more muted brown/ olive appearance. The juvenile of both sexes are similar to the colours of the female, being tannish brown or grey however,their colours will begin to match those of an adult boomslang once they reach 1m (3.2ft) in length. Male individuals native to the cape of South Africa tend to have a yellow appearance, but will also have jet black patterning on their dorsum, as pictured. Despite the differences listed between individuals in terms of appearance, some few features remain constant. Large eyes are a notable feature of all boomslang, with juveniles being born with emerald green eyes that slowly become brown/maroon in adulthood. The head of the boomslang is small and ovular and the snout appears downturned, unlike most snake species. The boomslang also has a noticeably gaping mouth, that stretches wide across its face. The mouth of the boomslang houses large rear-fangs, meaning the fangs are located around the mid to rear of the mouth and face the throat. There are fangs on either side of the boomslang's mouth that will inject a potent venom into those who are unfortunate enough to provoke the snake. The venom is delivered via glands located beneath the snake's eyes. The effects of the venom are explored more thoroughly in the Relationship with Humans section of this article. Boomslang are not particularly large snakes, only reaching 1m (3.5ft) in length however, some individuals may rarely exceed 2m (6.5ft).

## Diet

Being arboreal, boomslang hunt in trees, aiming to get as close to their prey as possible in order to perform an ambush. Boomslang typically eat various species of birds, lizards and rodents. The boomslang can open its jaw to 170˚ to expose its rear-fangs and depends more on its venom when compared to its bite force in order to kill its prey, using its rear-fangs to hold its prey securely until its venom can take effect on the animal. Boomslang will also take full advantage of their arboreal lifestyle, often eating eggs found in bird's nests.

## Conservation Status

Due to the boomslang's likely large population and widespread distribution, the snake is listed by the IUCN as least concern. The IUCN itself explains that "there are no major threats to this very widespread snake" and also that "It is unlikely that any specific conservation measures are required for the species", demonstrating that the boomslang is not immediately threatened by any human activity.

## Range and Population

The boomslang inhabits many countries and regions in sub-Saharan Africa, from their northern-most populations in Sudan to their southern-most in South Africa. Boomslang live most often in arid locations such as grasslands and savannas however, they do also inhabit areas of dense forest such as central Africa. In these environments boomslang will live almost entirely in trees, rarely venturing to the ground. The population of the boomslang is unknown however, judging by the species' wide range paired with its lack of major conservation issues, the population is most likely in a stable state

## Behaviour

Boomslang are extremely dependent on their arboreal lifestyle seldom climbing to the forest floor unless in hunting, basking, or moving between trees through thick vegetation. It can also be noted that when weather becomes harsh or unbearable for the boomslang, they will attempt to seek refuge underground. Like most snakes the boomslang will use its forked-tongue to determine what is present in its environment, via use of the 'Organ of Jacobson'. This vomeronasal organ is located at the back of the boomslang's mouth and aids in the detection of pheromones and other chemical signals. The Organ of Jacobson is essential for the boomslang as it allows the snake to determine what is in its immediate vicinity. During hunting the snake will freeze and shake its head slowly in a side-to-side motion after detecting prey. The slow swaying is used by the boomslang to make its body appear to be swaying vegetation, as to ambush its prey. Eventually, the boomslang will quickly attack its unsuspecting prey. Unlike many snake species, the boomslang's huge eyes allow it to hunt capably during the day. The breeding habits of the boomslang are very well documented. Female snakes will secrete a scent trail in order to lure males. Male boomslang will spar with each other in an effort to appear more dominant. The winning male will then obtain the rights to mate with females in the breeding grounds, while the loser will retreat in order to find females in a different territory. After the winning male follows the female's scent trail, he will inspect her until satisfied before copulation. After a gestation period of 60 days, the female will lay 8-27 'ping-pong ball' sized eggs during the mid Summer months. To prevent her eggs from drying and then dying, the female boomslang will aim to lay her eggs in a damp or wet location, such as a discarded burrow or tree hollow. After 65-100 days of incubation the eggs will hatch. After hatching, the 20cm (7.8in) hatchlings will shed their skin after 10 days. Despite the hatchling's small size and harmless appearance, they are born with the shared ability with their adult counterparts, to inflict lethal doses of venom.

### Relationship with Humans

Despite its extremely potent venom, the boomslang will not attack commonly unless severely provoked or threatened however, this does not mean the animal is necessarily approachable, the African Snake Bite Institute lists the boomslang as a 'very dangerous' species. Boomslang attack so uncommonly, that little bites occur annually in South Africa, with these bites mostly being inflicted upon snake handlers and game reserve attenders. The boomslang's venom is haemotoxic, meaning that it greatly compromises the victim's blood-clotting mechanism, which in turn leads to mass internal and external bleeding, organ failure and paralysis, which is always lethal or even fatal unless medical attention (such as antivenom) is received.The venom of the boomslang is slow acting, only producing effects after around 24-48 hours of infliction. The SANBI recommends that the following steps must be followed after being bitten by the boomslang. "**(1)** Immobilise the victim. The victim must lie down and keep as quite as possible. **(2)** Apply a pressure bandage immediately and immobilise the limb with a splint to reduce the spread of venom. **(3)** Loosen the bandage if there is severe swelling but do not remove the bandage. **(4)** Take the victim to the nearest hospital." Despite the boomslang's clearly extreme venom, the snake is extremely reluctant to bite especially when in trees. Although this is relatively common information, myths have become abundant surrounding the boomslang's behaviour. Many have spread rumours that imply that boomslang are extremely malicious snakes that attack unprovoked, in particular it is commonly said that the snakes will deliberately fall onto victims from trees above in order to bite them. Of course this is simply untrue. Another rumour tells of how the boomslang is not reluctant at all to climb into cars left vacant by humans. This rumour has a bit more weight to it, as this actually occurred at the Harold Porter National Botanical Gardens (though no one was hurt). Truly boomslang are very skittish towards humans and will never actively seek them out for conflict or bite without reason. Though boomslang do not seek out humans to begin conflict, it is said by the SANBI that bird aviaries located near human settlements may attract the snakes. When a boomslang is feeling threatened by you it will puff out its neck to appear larger, it is telling you that it wants to be left alone. A lot of the time, the green mamba ***(Dendroapsis augusticeps)*** and other more harmless species of green snakes are mistaken for the boomslang. These mistakes can lead to deaths in the case of the green mamba, as the snake is much more dangerous and aggressive when compared to the relatively docile boomslang. Methods in which to differentiate the two similar species include; reviewing the appearance of the snake, green mambas are larger and heavier, with smaller eyes and a longer snout, they are also much thicker in width when compared to the slender boomslang.

## In Captivity

According to ZOOINSTITUTES, the boomslang can currently only be found in captivity in Minsk Zoo, Belarus and Zoologika Zahrada Dvur Kralove, Czechia. In both zoos the boomslang are kept in reptile houses.

## Sources

* Boomslang - Predator and Prey | Tswalu - https://tswalu.com/boomslang-predator-and-prey/
* IUCN Red List of Threatened Species - https://www.iucnredlist.org/species/190603/15357215
* Boomslang | African Snake Bite Institute - https://www.africansnakebiteinstitute.com/snake/boomslang/
* Boomslang | SANBI - https://www.sanbi.org/animal-of-the-week/boomslang/
* Which Snake is Africa's Deadliest | African Geographic - https://africageographic.com/stories/which-snake-is-africas-deadliest/
* Boomslang | Kariega Game Reserve - https://www.kariega.co.za/blog/photo-boomslang-tree-snake
* Green Mamba Vs Boomslang - What are the Differences? | A-Z Animals - https://a-z-animals.com/blog/green-mamba-vs-boomslang-what-are-the-differences/
* Boomslang | ZOOINSTITUTES - https://zooinstitutes.com/animals/boomslang-600/