| 1 | Thirteen-scaled green snake |
Maximum length: 81.5cm.
The Congo rainforest is a vast area of untouched wilderness in central Africa, which spreads into 6 countries. The DRC holds the most area, but the Republic of Congo, Central African Republic, Gabon, Equatorial Guinea, and Cameroon also host large areas of the rainforest. Many areas are severely inaccessible, and consequently, there are endless native species which are poorly researched.
One example is the thirteen-scaled green snake (Philothamnus carinatus), which covers the vast majority of the Congo region, just reaching far western Uganda. This is a mysterious species, which also appears in clearings next to rainforests, and has immensely variable patterns. This is a green-black snake measuring 40-80cm, with neon blue cracks visible between its scales, which enlarge as they inflate their throats in anger.
This Congo rainforest snake undergoes a great shift with age. As juveniles, thirteen-scaled green snakes are a dull brown, and spend their lives rummaging around in leaf litter on the rainforest floor. As they age, both their colour and lifestyle transform; they become green with blue and black shades, and ascend high into tree branches.
Thirteen-scaled green snakes vary wildly in abundance. In one forest, they can be the most common snake, before randomly disappearing in the next forest. Their diet is a mystery, and likely contains frogs, similarly to other Philothamnus members. Their confirmed predators include the bird snake (Thelotornis kirtlandii), a fellow tree branch snake, which is found lower on this list. Thirteen-scaled green snakes also have an island population, on Bioko in Equatorial Guinea.
| 2 | African bush viper |
Maximum length: 79.9cm.
A venomous viper which primarily clings to tree branches, and moves only by night, with the savagely vertical pupils to prove it. The African bush viper (Atheris squamigera) stretches from Cameroon in the west, through the Congo rainforest, to southwest Kenya in the far east. This is a highly likely snake to stare at you menacingly from a jungled rivershore, while your boat sails uneasily down the Congo River.
The African bush viper is a short, though fairly thick snake. In a 2000 study, the maximum male length recorded was 67.0cm, and the maximum female length 70.5cm. Most of their diet consisted of mammals, particularly shrews in juveniles, and rodents in adults. African bush vipers regularly remain on the same branch for 48 hours, and are most common in lowland rainforests at altitudes of 100-400 metres. They particularly love forests with the densest, most tangled vegetation, amid rainfall totals of up to 10,000mm annually.
This snake has an immense colour variety, ranging from standard green to torquoise to orange. It’s possible that these morphs correlate to certain areas of rainforest, or that they’re totally random.
While not to be underestimated, bites by African bush vipers are rarely fatal. A 26 year old man was bitten twice on the foot by his pet in a 2022 report. He suffered minor sensitivity and swelling, and a reduced fibrinogen count of 121, below the healthy range of 180-500 mg/dL. But there’s also reports of a Central African Republic victim who died within 6 days, despite repeated blood transfusions and antivenom infusions.
| 3 | Western forest centipede eater |
Maximum length: 64.5cm.
A very indistinct snake, which is black and shiny like many of its Congo neighbours, sometimes with a pale neck collar. Western forest centipede eaters (Aparallactus modestus) reach a maximum of 64.5cm, but are more typically 35cm. Forest floors are their domain, in dense primary and secondary rainforest, and they range from Uganda through the Congo and DRC to Equatorial Guinea.
Western forest centipede eaters rarely appear near human habitation, but they do appear in thick plantations on the edges of forests. Only a few details are available for this species. A 1966 report mentioned a juvenile Aparallactus modestus coughing up 100 termites. This species is hiding behind a false name, as while the 11-member Aparallactus genus does hunt centipedes as a whole, this is a rare species to eat earthworms instead.
The difference is evident in its fangs. Other Aparallactus members have a rear fanged venom, designed to subdue dangerous centipedes. But Aparallactus modestus lacks the grooves in its rear fangs which this venom usually flows down. It’s therefore assumed to have a less developed venom system overall, as its slimy prey are far less dangerous.
| 4 | Banded water cobra |
Maximum length: 2.7 metres.
Out of the 20-25 cobras living in Africa, this species is easily the most restricted to rainforests. Banded water cobras (Naja annulata) are found in rivers within rainforests, as well as the thickly vegetated shorelines. They have a heavily neurotoxic venom, and aquatic adaptions such as a thinner neck hood than usual, reducing underwater drag while swimming. They can dive to depths of 25 metres, and easily remain submerged for 20 minutes per session.
Banded water cobras inhabit most of the Congo rainforest, including DRC, Gabon and Cameroon. They’re so different to other African cobras that along with Christi’s water cobra, they were once placed in the separate genus of Boulengeri, before being switched back to the main cobra genus of Naja in 2018. Banded cobras tend to flee rapidly if confronted by humans, escaping to the water where they feel comfortable. They lay 22-24 eggs per clutch, and fish dominate their diet.
Banded water cobras cause relatively few bites, yet are still capable of dealing out death. A 2022 newspaper report detailed a fisherman in Nyanga, the southernmost province of Gabon. A mystery snake became entangled in his fishing net, and sank its fangs into his thumb. The man attempted to kill his serpent assailant with a stone, but died a few minutes later, after mentioning feeling very cold. Scientists reading the newspaper identified it as a banded water cobra, based on patterns in a still image.
Banded waters cobras average at 1.8 metres, and occasionally push to 2.7m. The Latin name of Naja annulata is not to be confused with Naja annulifera, AKA the snouted cobra, a southern Africa species.
| 5 | Ornate African water snake |
Maximum length: 152cm.
A semi-aquatic snake which feeds overwhelmingly on fish, and occasionally amphibians. Ornate African watersnakes (Grayia ornata) are everywhere in the Congo region, ranging from western Uganda to Equatorial Guinea. Their habitats are essentially rivers and streams through thick forests, similarly to the banded water cobra. Their patterns are also similar: a slimy olive base contrasting vividly with thick black stripes. It’s possible that this species is mimicking its deadly neighbour in order to gain a protective shield.
This harmless snake likes to hide in holes in muddy river banks, and has local names such as dibomina and moléngué. Ornate African water snakes are especially common in the Likouala region of the Republic of Congo. They’re so common that fishermen often scoop them up in their nets by mistake. Supposedly, otters love the taste of Grayia members, and will try to rip apart nets to acquire them.
Grayia ornata has a particularly long scroll of local folklore in Gabon and beyond. The locals eat this snake, believing it to taste best during dry season when it becomes fattest. Its medicinal powers apparently include improving delivery for birthing women, improving fishing and swimming abilities, treating sprains and aiding newborn babies.
Despite being heavily aquatic, ornate African watersnakes are also spotted hanging from branches directly above streams. They ascend to perches 2-3 metres high, and then plummet instantly into water when spooked. This makes them something of a parallel to the brown watersnake of the southern US.
| 6 | Mocquard’s African ground snake |
Maximum length: 45cm.
Part of the small Gonionotophis genus, which contains just 3 snakes, all humble forest floor dwellers. If Mocquard’s African ground snake (Gonionotophis brussauxi) had its way, it would never emerge from its cosy forest confines.
This species spends most of the day comfortably ensconced in leaf litter or a hollow log, shielding itself from the treacherous rainforest. Mocquard’s African ground snake is a species of primary forests or dense secondary forests, making them very difficult to find. Thick vegetation on the forest floor is ideal for this species, aiding their schemes of disguise further.
This snake has an average length of 30-40cm. Its scales are black, while the white markings are actually the interstitial skin between its scales. The diet of this species is poorly researched, but thought to mainly consist of ground-dwelling frogs. Mocquard’s African ground snake is found in Gabon, DRC, Republic of Congo, Central African Republic, and reaches Uganda to the extreme east.
Mocquard’s African ground snakes are nocturnal, moving only under pitch black darkness. Combined with their dark colours, and the thick jungle squeezing out any faint traces of light, this snake is incredibly difficult to spot.
| 7 | Marsh snake |
Maximum length: 49.2cm.
A harmless snake which evolved and lives in rainforests, usually close to rivers, streams and marshes. The marsh snake (Natriciteres fuliginoides) averages at just 20-30cm. It’s rare to find this snake away from water, and its diet consists of amphibians such as golden puddle frogs (Phrynobatrachus auritus).
Forest swamps are one of the best places to find this species. Marsh snakes are found in many countries – Gabon, Congo, DRC, Equatorial Guinea, but are rarely sighted because of their love for deep forests.
The marsh snake is excellent at thermoregulation – it’s able to maintain a consistent and optimal body temperature with very little effort. In many areas of the Congo rainforest, they coexist with their cousin, the variable marsh snake (Natriciteres variegata).
A 2002 study tested whether their presence inspired heavy competition between them. It found that when the two species coexisted, marsh snakes were more likely to 1) eat prey from land, 2) switch to focussing on smaller prey, and 3) shift towards invertebrate prey, and away from vertebrates. It’s possible that N. variegata is a stronger hunter than the marsh snake, forcing it into niches it is less adapted to.
| 8 | Laurent’s tree snake |
Maximum length: 124cm.
Dipsadoboa is a snake genus with 12 members, which all love trees, but aren’t necessarily rainforest-dwelling. Laurent’s tree snake (Dipsadoboa viridis), meanwhile, is a diehard rainforest snake, appearing in true Congo rainforest nations such as Gabon, Cameroon and DRC.
This species is often found on branches directly overhanging small streams within rainforests. When confronted, they kink their bodies into strange shapes, designed to mimic vines and foliage. If found on the forest floor, they sometimes coil into a tight ball in order to hide their head. Luckily, hundreds of thousands of this species will never even meet a human, as they regularly live in the deepest regions of the Congo, such as Gabon’s Mwagna National Park.
Laurent’s tree snakes mainly feed on reptiles and amphibians, including ridged frogs (Ptychadena). They take their prey down using a rear-fanged venom, whose exact effects on humans remain unknown. Rainforest swamps are another great place to find this secretive species. Their absolute favourite habitats are lowland rainforests, and they also appear in cacao and banana plantations close by.
Laurent’s tree snake is an egg-laying species, pumping out batches of 3-5. They average at 70-100cm, and one of their relatives is the marbled snake of Mozambique (D. aulica), which appears more commonly in savannah.
| 9 | Bird snake |
Maximum length: 180cm.
One of the most abundant snakes in the Congo rainforest region. The bird snake (Thelotornis kirtlandii) is also one of the Congo rainforest’s longer snakes, at up to 1.8 metres. At birth, they measure 25-30cm.
The bird snake is a tree-dwelling snake, with the signature ability to expand its throat to bizarre levels, like a pelican about to swallow a fish. Its venom targets blood coagulation, disrupting clotting elements and causing uncontrollable bleeding. There’s no dedicated antivenom for this species, and one confirmed death happened to an 80 year old woman, who died from kidney failure.
Bird snakes don’t instantly fly into a panic when humans approach. They often keep their cool, ignoring the intruders into their deep forest domain. Should you touch them, however, they’ll instantly erupt into a vicious assault.
Bird snakes lay particularly long, thin eggs, and they occasionally lay these eggs in ants’ nests. Popular prey for this snake include Ploceus weaverbirds. Alongside the thirteen-scaled green snake, they’re a confirmed predator of the emerald snake. A 1998 study examined a swamp in southeast Nigeria, and recorded the banded-leaf toed gecko seven times as prey, as well as a rufous-winged cisticola. Reptiles and occasionally birds seem to be their main menu items.
| 10 | Blackbelly snake |
Maximum length: 90cm.
A moderately sized rainforest snake, which has no ill intentions towards humans. The blackbelly snake (Hydraethiops melanogaster) inhabits the western portions of Central Africa: Congo, Gabon, Equatorial Guinea, and Central African Republic.
This is a semi-aquatic snake, which preys mainly on fish. Rainforests are its domain; you’ll never find the blackbelly snake in a small rain pool in a dry savannah.
Up close, this snake has fairly complex patterns. There’s a creamy stripe beginning from each eye, ending after the neck. Its body is a murky brown, but overlaid with dozens of black, diamond-shaped markings. Because these are so small, they fade away at a distance, making the blackbelly snake look deceptively dull from far away. Its head is fairly distinct from its neck (though not triangular like a viper’s), and its eyes are fairly small, with round pupils rather than vertical.
This is believed to be a non-venomous snake, though several non-venomous snakes have turned out recently to secrete a mild rear-fanged venom. The Hydraethiops genus has just two members, the other being the even rarer Hydraethiops laevis, also found in the Congo rainforest.
| 11 | Green bush snake |
Maximum length: 98.6cm.
A harmless species with barely any research to its name. The green bush snake (Philothamnus nittidus) is found in a decent handful of African countries, including Ghana, Nigeria, Equatorial Guinea, Gabon, Congo, and the DRC, yet is rarely observed. This is a dedicated forest species, spending most of its life on tree branches. Its diet most likely consists of amphibians such as frogs.
At first glance, green bush snakes are uniformly green like many of their Philothamnus relatives. They also have the usual round pupils, and large bulging eyes. However, a subtler ID sign is a whitish throat and chin, contrasting against a paler green underside.
Like many snakes of the Congo rainforest, this is a mysterious species, with barely any research to its name. Even for scientists with state of the art equipment, hacking their way into an overgrown jungle where banded forest cobras and poisonous frogs could be around any corner is no joke.
Of all Congo rainforest snakes, this is undoubtedly one of the froggiest in appearance. The original holotype from 1946 measured 81.3cm, while the all time record was slightly under 1 metre.