BIOLOGY

Never handle a that you cannot identify. GREEN ALERT With the weather warming and the mating season beginning, will be more active, so be on the lookout. These green-coloured are particularly well camouflaged. By Robin and Bryan Maritz

TIP Scan the sunny parts of vegetation during mid-morning for your best chance to glimpse a Dendroaspis green-coloured snake. angusticeps

arely discernible among the vegetation, using their Life in the canopy they blend into perfectly, they venture green colouration to blend in, are seven of South Afri- The most arboreal and graceful of onto ground in search of a ground- ca’s snake species. When you spot a green snake in the the green snakes is the eastern green dwelling bird or mammal on rare Btree canopy or a leafy bush, the species may appear similar mamba Dendroaspis angusticeps. Al- occasions. Unlike snakes which use at first glance; identifying them from a fleeting glimpse or a though green mambas occur widely constriction to immobilise prey, the low-resolution photograph is often impossible. Instead, note across the continent, in South Africa highly venomous green mamba injects where the snaked occurred. While some of these diurnal, they are limited to coastal lowland a complex mixture of proteins that in- green-coloured snakes are almost entirely arboreal, a few of forests in KwaZulu-Natal. Found pre- terfere with the functioning of nerves the species find life on the ground to be more suitable. PING TYRONE dominately in the tree canopy, which and muscles, including the heart.

44 WILD SPRING 2019 www.wildcard.co.za SPRING 2019 WILD 45 BIOLOGY Boomslang Dispholidus typus Spotted bush snake Philothamnus semivariegatus

As indicated by their rather large eyes, boomslang have acute vision and are very alert snakes.

Life at the interface belonging to the Philothamnus, the Boomslang, meaning ‘tree snake’ in Af- true green snakes, are the most common- rikaans, are known for their climbing ly encountered green-coloured snakes abilities and are frequently encountered in South Africa. These species are much Southeastern green in trees and shrubs, sometimes even in skinnier than boomslang and green snake or green thatched roofs. We spend a lot of time mambas. All four green species in South water snake Philothamnus looking into camel thorn and blackthorn Africa have a thick black ring encircling hoplogaster trees for boomslang as part of our re- their iris, which boomslang and green search in the Kalahari, and can confirm mambas lack. They can be challenging to that their green colouration is highly differentiate due to variability in colour effective camouflage. patterns and similarity in body shape. Only a subset of male boomslang are Herpetologists often rely on counting completely green. Males in the Western the number of scales on the head, and and Eastern Cape are black, green and noting their placement, to differentiate yellow. Females throughout the range between species. are typically brown in colour. Adding to Green snakes are agile climbers and the complexity, juveniles (<80 cm) have several of the species are skilled swim- a completely different appearance, with a mers. It is not uncommon to see them on dark-coloured back, light underside and the ground. The most arboreal species is Eastern Natal green snake large green eyes. the spotted bush snake, readily found in Philothamnus While boomslang do spend time bask- woodland habitat. They are commonly natalensis ing and hunting in trees and shrubs, they encountered basking or hunting in gar- spend a reasonable amount of time on dens and may well be seen trying to swal- the ground either resting among vegeta- low a foam nest frog. Of the true green tion, moving between areas or hunting snakes, the southeastern green snake, prey. As indicated by their large eyes, sometimes referred to as the green water boomslang have acute vision and are very snake, is the least arboreal and may be alert. They are highly venomous, using a seen swimming or even eating a fish, al- cocktail of venom proteins to cause in- though their diet consists mostly of grass Western Natal green snake ternal haemorrhaging in their prey. Their frogs and river frogs. The remaining two Philothamnus diet consists of chameleons, bird chicks green snakes are similar to each other occidentalis and bird eggs. Listening for birds sound- and researchers concluded only recently ing their alarm calls is a great way to find that they are distinct species. Notably, a hunting boomslang. the eastern Natal green snake prefers a well-forested habitat in the lowveld, True green while the western Natal green snake is Although regularly misidentified as a found more commonly in moist savanna LUKE AND URSULA VERBURGT (ENVIRO-INSIGHT) AND URSULA VERBURGT LUKE boomslang or a green mamba, snakes and at forest edges.

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Western Natal green snake scales Philothamnus occidentalis

Many-spotted snake Amplorhinus multimaculatus

Several of the true green snakes can Who’s who? A closer look at be quite aggressive and often bite if SA’s green-coloured handled. Unlike green mambas and snakes reveals a boomslang, true green snakes are remarkable collection of ecologically diverse TRUE GREEN SNAKES TRUE GREEN SNAKES not considered dangerous to humans species. Here’s because they lack potent venoms. how they differ in WESTERN NATAL EASTERN NATAL SOUTHEASTERN SPOTTED MANY-SPOTTED EASTERN BOOMSLANG Although they are considered non- respect of behaviour, habitat preference, GREEN SNAKE GREEN SNAKE GREEN SNAKE BUSH SNAKE SNAKE GREEN MAMBA venomous, their saliva is thought to distribution, venom HARMLESS HARMLESS HARMLESS HARMLESS MILDLY HIGHLY HIGHLY contain a toxin that paralyses their and feeding choice. VENOMOUS VENOMOUS VENOMOUS prey, which makes swallowing easier. SCIENTIFIC Philothamnus Philothamnus Philothamnus Philothamnus Amplorhinus Dendroaspis Dispholidus Life on the ground NAME occidentalis natalensis hoplogaster semivariegatus multimaculatus angusticeps typus

Many-spotted snakes Amplorhinus TYPICAL SIZE 80–90 cm 80–90 cm 50–60 cm 70–90 cm 40–50 cm 160–180 cm 110–140 cm multimaculatus are brown with a series of spots that runs along their FREQUENTLY In shrubs and trees in In shrubs and trees Near water in lowland In shrubs and trees Marshy vegetation in In tree canopy in In shrubs and trees FOUND wooded grassland in lowland forest forest, wooded grassland, in lowland forest fynbos and grassland coastal lowland forest in all but most arid back. However, rare bright green and savanna savanna and fynbos and savanna habitats and olive morphs have been found in Mpumalanga, KwaZulu-Natal and ARBOREALITY ++ ++ + ++ - ++++ +++ the Eastern Cape. Look out for them REPRODUCTION 4–6 eggs 4–6 eggs 5–6 eggs 6–12 eggs 4–5 live young 8–10 eggs 10–14 eggs among reeds near water as well as on fynbos or grassland slopes. Of the COMMON PREY Frogs, geckos, skinks Frogs, geckos, skinks Frogs (grass, river, reed) Foam nest frogs, Frogs and small Birds (all ages), Bird (chicks and eggs), geckos, skinks mammals rodents chameleons green-coloured snakes, this species is the least arboreal and the most ID CLUES Blue hues on Head flatter than Smallest and thickest Heavy black spotting Stocky for its length, Big-bodied, slender Big-bodied, very elusive. Little is known about their head and tail P. hoplogaster of the Philothamnus on front half fading into indistinct head coffin-shaped head large eye, short head a bronze-coloured tail venom composition but it may cause irritation in humans. Although few DISTRIBUTION feeding observations exist, they are thought to prey on ground-dwelling

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rodents and frogs. PING TYRONE / (ENVIRO-INSIGHT) VERBURGT URSULA AND LUKE

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