| 1 | Aesculapian snake |
Maximum length: 225cm.
The most tree-loving snake in Italy, and one of Italy’s longest snakes, reaching a maximum of just over 2 metres. Aesculapian snakes prey on mammals such as bank voles and black rats, and inhabit forests both dark and sparse. They’re a species surrounded by folklore, as they were named after the god of healing Asclepius, who supposedly built healing temples where they slithered over patients while they slept.
Of all Italian snakes, this is the most likely to be found in dark, claustrophobic forests with barely any light. The Aesculapian snake is perfectly fluent in tall trees, ascending them with barely any effort at all.
Part of this is experience, but most of it is instinct developed over millions of years. As well as fully-fledged forests, they can appear in isolated tree clumps by meadows, villages or even schools.
Aesculapian snakes are a harmless constrictor, which lacks any form of venom. As well as Italy, they’re a common species in France, Greece, Albania, far northern Spain, Austria, Macedonia and many more. There’s also a small invasive population in the UK. Aesculapian snakes are much more at home in trees than humans can hope to be, except maybe when it comes to cutting them down.
| 2 | Ruschenberg’s tree boa |
Maximum length: 250cm.
A relative of the Amazon tree boa, ringed tree boa, and other Corallus tree boa members. The Ruschenberg’s tree boa (Corallus ruschengergii) is found in Colombia, Venezuela, Costa Rica and particularly Trinidad, where it hisses at people from eye level, or more specifically, from a tree branch perch.
This species is a non-venomous constrictor, which sometimes crosses open ground to find a more bountiful ambush site. However, they much prefer to stay in trees all day long, whether at mid-height or 10 metres high in the canopies. Rather than being secretive, Corallus ruschenbergii is encountered regularly by Trinidad locals, who dub it the “dormillion”.
Ruschenberg’s tree boas measure up to 2.5 metres, but are relatively thin for a constrictor, to allow effective balance on branches. Their diet mainly consists of rodents.
As a nocturnal snake, this species can be tricky to spot, but there’s one great secret – their eyes reflect torchlight incredibly well. This is a trait found in most Corallus tree boas. Scan around with your handheld torch, and you may witness a pair of glowing white orbs appear in a tree, side by side, followed by a hissing serpent manifesting as though it’s just teleported.
| 3 | Western mangrove catsnake |
Maximum length: 2.5 metres.
A southeast Asian tree snake which regularly exceeds 2 metres. Western mangrove catsnakes (Boiga melanota) are common in southern Thailand, peninsular Malaysia, Singapore and Sumatra, and are extremely easy to recognise due to their yellow-black colours.
Recently, their venom turned out to be slightly deadlier than once believed. A study found several rare neurotoxins in its venom, including irditoxin, boigatoxin-A, and denmotoxin. However, one fact has been known for hundreds of years: that mangrove catsnakes love to rest in trees. This species can appear both in deep forests and in tree close to towns and villages, where they spend virtually all day resting on branches.
Mangrove catsnakes have innate balance. They’ll never accidentally snap a branch and plummet to the hard floor, nor let their mind wander and fall down. If in danger and faced with a choice of escape, a mangrove catsnake will always travel upwards into a tree, whereas a monocled cobra would nearly always travel downwards into a burrow.
Mangrove catsnakes have never killed anyone, but according to a 1991 report, a keeper who was bitten experienced fatigue, listlessness, kidney pain, a metallic taste, nausea and intense pain. Fortunately, this is a rear-fanged snake, which must chew victims for at least 30 seconds to actually inject venom.
| 4 | Sawtooth-necked bronzeback |
Maximum length: 163cm.
A 80-100cm Thai species which preys mainly on frogs, similarly to other bronzeback members. Sawtooth-necked bronzebacks (Dendrelaphis nigroserratus) are found exclusively in western and southern Thailand, possibly over the border in Myanmar, and were only confirmed as an independent species in 2012.
This harmless species is most often seen intertwined with a thin branch, with jungle colours that almost resemble a tiny alien creature. They’d stand no chance in a war with monocled cobras and reticulated pythons, and that’s why they’ve chosen their humble branch niche instead.
Sawtooth-necked bronzebacks are found on branches in forests around two thirds of the time, usually 1-2 metres above ground. They stray to the ground occasionally, but tree branches are where all their skills of nimbleness, balance and agility come to the fore. They’ve also been found resting on bamboo stalks.
Sawtooth-necked bronzebacks are superficially similar to other bronzeback species, but are identifiable by their namesake patterns: continuous black zigzags running down their entire body in a sawtooth pattern. There’s thick black line near each eye as well, and their tongue is mostly red.
| 5 | Common Madagascar cat snake |
Maximum length: around 1 metre.
Madagascar’s main tree snake. This is a thin-bodied species which weaves along thin branches, and rapidly accelerates if necessary. They average at 80-90cm, and inhabit most of Madagascar, from north to south.
Rather than bright green camouflage, this species relies on speed and nimble acrobatics for its survival. Madagascar cat-eyed snakes (Madagascarophis colubrinus) are happy to appear in fully forests and degraded human zones alike. As long as tree clumps are standing, they can survive and thrive. They appear in trees in villages, gardens, outside town halls, near cocoa plantations. Building your dream house by a forest gives them a corridor directly to your bedroom windowsill.
Madagascar cat-eyed snakes have a supposedly mild venom, which nevertheless contains a neurotoxin called maculotoxin, discovered just last year (2023). However, the chances of being bitten are extremely low.
Madagascarophis colubrinus drops to the ground when necessary, but they’re most at home on tree branches, for which every aspect of their body is fine tuned, including a thin body width. They’re capable of stalking and grabbing prey high in trees, including chameleons and hatchling birds.
| 6 | Mexican parrot snake |
Maximum length: 140cm.
Part of the 19-member Leptophis group, the most common being the giant parrot snake. Mexican parrot snakes (Leptophis mexicanus) live from eastern Mexico to northwest Costa Rica, inhabiting 7 countries overall.
Mexican parrot snakes spend most of their day on branches, preferring moderately high perches rather than low bushes or 20 metres high. They prey on iguanas and anoles, and fully exploit their arboreal environments, investigating crevices in tree trunks for lurking prey. Mexican parrot snakes are completely familiar with their home tree, and know instantly when anything is inconsistent.
While only mildly venomous, parrot snakes are infamous for their crazed facial expressions, as they gape their mouths open wildly while trying to intimidate people. As a branch-dwelling snake, their demented face could be just inches from yours, if you accidentally stumble into their forests.
Guatemala has over 130 snake species, while Costa Rica has over 135. Flexible as snakes are, there’s no way they can all coexist in the same habitats without destroying each other. Consequently, Mexican parrot snakes have taken to branches to avoid the bushmasters and lanceheads prowling around below. Even here, they face competition from the likes of Imantodes tree snakes.
| 7 | Tiger ratsnake |
Maximum length: 2.7 metres.
The tiger ratsnake (Spilotes pullatus) is a mega common snake which ranges from Mexico to Argentina, spanning the entirety of Central America and most of the Amazon region. Within those lands, they can be found in a variety of places: the ground, roofs of houses, dark burrows, and resting comfortably on high branches with a content facial expression.
Tiger ratsnakes are a comfortable, confident species in the towering canopies of trees. They easily ascend vertical trunks, or leap between thin branches. One was found 13 metres high in a fig tree in Panama, and refused to come any lower than 12 metres.
Trees are important for their life strategies, as the tiger ratsnake is a top bird’s nest raider. They’re confirmed to eat trogons and rufous-bellied thrushes, although one time, a gang of thrushes was seen mobbing a tiger ratsnake, causing it to retreat. Tiger ratsnakes also snatch Jamaican fruit bats and black mastiff bats from dark crevices in the roofs of houses, and by draping themselves over tall trees, they have a far superior view as to where these bats are hiding.
Even when hunting on the ground, tiger ratsnakes will drag their prey up trees to actually swallow them. One snake captured a fluffy Deppe’s squirrel, but wouldn’t begin feasting until it had ascended an additional 3 metres.
| 8 | Guatemalan palm pitviper |
Maximum length: 100cm.
This venomous snake chose tree branches millions of years ago, and is now fully adapted to them. Guatemalan palm pitvipers (Bothriechis bicolor) measure 60-80cm and have a small range, inhabiting border areas between Guatemala and extreme southern Mexico. Here, they coexist with fer-de-lances and coral snakes, but are far less common than both.
Bothriechis bicolor is an arboreal viper, preferring perches 1-2 metres high. They effortlessly coil around thin branches, remaining stationary in ambush position, and springing forward with propulsive force when prey (or a lost human explorer) wanders past.
Being rare, Guatemalan palm pitvipers don’t attack scores of people, but their bite isn’t something to take lightly. Forests near plantations are a danger zone, and the plantations themselves. This species contains few neurotoxins, instead producing the usual viper recipe of cytotoxins (necrosis, swelling) and haemotoxins (spontaneous bleeding).
A 2020 IUCN report deemed this species to be “vulnerable” to extinction. But the Guatemalan palm pitviper still has one advantage which nobody can take away: slithering up a mossy tree trunk with no effort at all.
| 9 | Green mamba |
Maximum length: 230cm.
The black mamba’s cousin, which inhabits coastal southeastern Africa, and spends vastly more time in trees. Green mambas have speed when they need it, with a lightning strike and blinding lunge for bird prey. But unlike the twitchy black mamba, they’d much rather drape themselves peacefully over a branch all day. Their green colours make them tricky to spot for people wandering below, despite an average length of 1.5 metres.
Green mambas specifically choose areas of thickly overlapping branches, to create a protective cloak of foliage they can vanish into. They have a regular daily cycle: begin on high branches, shift a few metres downwards for an active ambush session, then retreat to the safety of the canopy later in the day. Every so often, they embark upon a longer migration to a fresh tree.
Because of their tree-dwelling lifestyle, bites are far rarer than with black mambas. Their venom contains the usual alpha-neurotoxins responsible for laboured breathing, but virtually no deaths have been recorded.
The green mamba’s love of trees is reflected in its diet. Black mambas eat 81.5% mammals and 18.5% birds, but this ratio shifts towards birds in green mambas, at 42% versus 58% for mammals.
| 10 | Brown vine snake |
Maximum length: 200cm.
This 100-150cm species lives near the green anaconda, but lives the opposite life. While the latter is bulky and cumbersome, the brown vine snake (Oxybelis aeneus) nimbly ascends branches with the agility of an acrobat.
This species live in forests and their outskirts, sometimes scaring people by hissing from trees. It’s unknown whether this snake is dangerous to humans, though its cousin the green vine snake can cause pain and swelling. Brown vine snakes have a highly specialised venom, which is mildly toxic against mice and geckos, but significantly more lethal against Anolis lizards.
The brown vine snake takes mere minutes to climb a gnarly, warty rainforest tree. Being fully vertical on a trunk doesn’t bother them. Their camouflage is absolutely immense, perfectly mimicking a parched tree branch. Their territory is equally impressive, spanning Brazil, Venezuela, Columbia and French Guiana.
Brown vine snakes have the usual features for climbing trees, such as a thin body which minimises the weight at any given point. It’s unknown precisely how high they reach, whether towering at 20 metres or preferring 1-3 metre perches, but it would be surprising if they didn’t regularly exceed 10 metres.