| 1 | Aruba rattlesnake |
The world’s most endangered rattlesnake, and one of just 3 snake species native to Aruba. This scenic island lies off the northwest coast of Venezuela, and is a sun-drenched tropical paradise popular with Florida holidaymakers. The island is heavily urbanised, with at least 106,000 residents packed into a relatively narrow area.
Consequently, the native Aruba rattlesnake (Crotalus unicolor) has been pushed back to a mere 62km zone on the island’s dry southern tip. It’s estimated that only 230 Aruba rattlesnakes survive, exclusively in the island’s Arikok National Park. The IUCN has listed the species as critically endangered since 2007.
This snake lives in a harsh and dry habitat covered with thorny acacia bushes and cacti. Aruba rattlesnakes have faint diamond-shaped markings, and occasionally have dull colours, but can sometimes be an unusual pink instead.
This rattlesnake isn’t completely forgotten, as Aruba’s official currency, the florin, bears its slithering image. Education programs have also toured Aruba since 1988, to combat the instinctive fear locals have. Newspapers and magazines eventually joined the program, presenting glossy spreads about the rattlesnake’s misconceived aggression, discussing its actual calm nature.
An ex-situ breeding program is now underway, and consequently, the Aruba rattlesnake may well survive yet.
| 2 | Albany adder |
This severely endangered snake lives exclusively in the eastern cape of South Africa. It’s restricted solely to Coega Bontveld ecosystems, dry landscapes of mixed thicket and scrubland, which are under severe threat due to strip mining for limestone pavement.
Barely anything is known about this venomous South African snake, except what the handful of existing photographs reveal. The Albany adder averages at less than 30cm, and is brown and tan to blend with parched soils.
Like its dwarf adder cousins, the Albany adder has horn-like masses of scales above its bulging eyes. It was first discovered in 1937, and over 50 years then passed until the next sighting in the 1990s. This was followed by another drought, as despite the march of technology, only a single sighting appeared over the next 20 years (2007).
So in late 2016, a Rainforest Trust and Endangered Wildlife Trust team set off to South Africa to track down the Albany adder for good. Despite 6 days of constant rummaging and scouting, they only discovered a handful of snakes at the eleventh hour.
The team had arrived just in time, as there were mere months remaining before the 10 year sighting deadline passed, after which a critically endangered animal is officially declared extinct. It was a heroic effort, but the future remains bleak, as Coega Bontveld ecosystems continue to be pushed back by mankind.
Albany adders are so unresearched that there are no images we can legally display, so check out this video instead.
| 3 | Crocker’s sea snake |
This is one of two purely freshwater seasnakes in the world. Crocker’s sea snake (Laticauda crockeri) not only lives on a single island, but in a single brackish, inland lake.
The location is Rennel Island, part of the Soloman Islands located to the northeast of Australia. The lake is Lake Te-Nggano, which is also home to the common banded sea krait (Laticauda colubrina). Crocker’s sea snake is most closely related to the black-banded sea krait (Laticauda laticauda), but is believed to have become isolated by sea level or geographical changes. It was propelled down a new path of evolution, with a similarly neurotoxic venom, but a smaller body size and darker appearance.
The big problem facing Crocker’s sea snake is that due to being stranded in one location, an ecological disaster could easily destroy them. The plus side is that Rennel Island is a traditional place of wooden houses and fruit, rather than scorched, smoke-fuelled industry.
A study found that Crocker’s sea snake is unable to breed with the banded sea krait it coexists with, proving the two to be fully independent species. Within the lake, the two species have separated into their own dietary niches, with the banded sea kraits focussing on Anguilla eels, and Crocker’s sea snake focussing on Eleotris goby fish. While the banded sea kraits regularly stray to the lake’s sandy shores to rest, Crocker’s sea snake sticks firmly to the water.
| 4 | Anatolian meadow viper |
This Turkish viper lives solely at elevations of over 1500 metres, in mountainous sky islands elevated far above the surrounding countryside. This is fun for lording it over other species like a serpent god, but not ideal if you want a large amount of territory to roam in.
The Anatolian meadow viper (Vipera anatoli) diverged from other vipers an estimated 5 million years ago, and is separated from them by hundreds of kilometres. It mainly lives in the Ciglikara mountain plateau, although a new population was discovered in the Geyik Mountains in 2017. This species is venomous like others vipers, and moves unbelievably quickly, striking so fast that a camcorder can barely keep up. This is designed for its grasshopper-rich diet.
The Anatolian meadow viper is completely missing from lower altitudes, as the surrounding Turkish lowlands become far too hot in the summer, exceeding 37C, the species’ upper temperature limit. Essentially, this viper is stranded, and therefore massively vulnerable to extinction. With heavy mining activity and quarries, the pressure rises further.
The Anatolian meadow viper was discovered by accident in 1969, by an expedition searching for another endangered animal, the woolly dormouse. In 2013, researchers returned to the Ciglikara mountain plateau and struggled for days to find one on rugged rocky slopes.
Finally, a fully grown Anatolian meadow viper appeared, and the floodgates opened, with over a dozen more appearing in quick succession. Others weren’t so lucky: researcher Harry Sigg spent months searching in the 1980s, and only found 1.
| 5 | Cropani’s tree boa |
Dubbed the world’s rarest boa, Cropani’s tree boa (Corallus cropanii) was originally discovered in 1953, and known only from a single sighting.
South America is littered with ghost snakes that were documented once and never reappeared, and over the next few decades, the only fresh evidence for this boa that ever showed up was a handful of dead individuals. The species’ habitat was the Atlantic Forests of eastern Brazil, near São Paulo, which were becoming increasingly slashed down.
Conservationists put out a forest-wide alert, but it took 60 years for another sighting of a live individual to emerge. In 2017, their prayers were finally answered, as a fully grown Cropani’s boa was found by local Brazilian villagers. It had a beige body with sharply contrasting splashes of brown, and measured 1.7 metres. It had the usual primitive head of boas, but more on the goofy side rather than cruel.
For once, this was captured by locals instead of western scientists, who had been taught to store the snake safely in a plastic bucket. Previous locals had beaten them to death, as its relatives had a reputation of being “a bit bitey”.
Aside from a strong attraction to trees, barely anything is known about Cropani’s tree boa. One fact involves their hunting, as this species drags its prey onto a high branch perch before swallowing.
| 6 | McGregor’s pitviper |
A rare pitviper, which lives solely on the small Batanes Islands off the far northern coast of the Philippines. MacGregor’s pitviper (Trimeresurus mcgregori) measures around 1 metre, and mainly inhabits seasonal rainforests receiving slightly lower quantities of rainfall, at around 2000-3000mm per year.
This snake is always found below 300 metres in altitude, and mainly preys on mammals. It was named after Richard McGregor, the first man to ever collect one, who even survived its venomous bite.
This pitviper is very variable in the wild – some are chocolate brown, some have leopard patterns, while others are white with black markings. Unfortunately, these flashy colours have made MacGregor’s pitviper very popular in the international pet trade. Many specimens are harvested from the wild, and consequently, this species is considered to be one of the top 30 endangered vipers worldwide. With their very small island base, there’s nowhere for this species to flee to.
Thankfully, efforts have been underway since 2000 to save this species. This breeder mastered the art of raising T. mcgregori, and ultimately produced several hundred, which he released back into the wilds of the Batanes Islands, with the cooperation of local officials. The governor of the Batanes Islands was all set to make their habitat a projected zone.
| 7 | Antiguan racer |
In the late 1990s, the Antiguan racer was considered to be the rarest snake in the world, before a strong recovery which saved it from disappearing forever. This is a grey-coloured, 1 metre snake which preys primarily on anoles, and poses no threat to mankind. Before European colonists arrived, this species roamed Antigua with no restrictions, with very few natural predators, exploring the island’s many forests at its leisure.
The first blow came when these forests were replaced with vast sugar plantations. The second blow came when legions of invasive black rats disembarked from European ships. Farmers released the Asian mongoose to combat these rats, but instead, they attacked the Antiguan racer, crippling its numbers.
By 1936, the Antiguan racer was believed to be extinct. In the 1960s, it was sighted on the nearby Great Bird Island, which was considered to be the snake’s last gasp. But in 1995, reports of survivors from the island could no longer be ignored. This mongoose-free island turned out to be the Antiguan racer’s last refuge on Earth, with a mere 51 adults surviving.
Rats had already invaded the island, and were gnawing at the snakes’ tails. The scientists soon got to work, and positioned wax blocks laced with the anticoagulant poison brodifacoum all over the island. Some team members were forced to climb crumbling cliffsides to ensure that no spot was missed.
By 2000, the Antiguan racer was still languishing at a mere 81 adults. But by 2010, numbers had risen to 100, and the conservationists switched their attention to nearby islands such as Green Island.
The Antiguan racer remains seriously endangered, but as of 2022, but its population is now estimated at 1000.
| 8 | St Lucia Racer |
Possibly the world’s rarest snake. This species has fallen into the exact same scenario as the Antiguan racer.
The St Lucia Racer (Erythrolamprus ornatus) was once widespread across St Lucia, in forested realms later decimated by sugar plantations. Their numbers plummeted further when the snake-hungry Asian mongoose was introduced in 1872, and by 1936, they were officially declared extinct. Hope was revived with a single sighting in 1973, but that was it for the St Lucia racer for 39 years. Not one scientific report came in, not even a sketchy sighting from a local farmer.
In 2012, a team of scientists scoured St Lucia, searching for any sign of the lost species. Their search took them to Maria Major, a small island 800 metres off the St Lucia mainland.
The scientists knew that this rocky, uninhabited island was free from mongooses, and after 5 months of relentless searching, they found 11 St Lucia racers, which were perhaps the species’ last survivors, after millions of years of evolution. They estimated that 20 remained in total, meaning that genetic diversity was a serious issue. The 11 snakes were radio-tagged, and set to provide 10 years worth of data.
The St Lucia racer is a brown snake with green tinges, and occasional yellow spots. It has a timid disposition, and reaches 1.25 metres long. Maria Major is also a refuge for the Saint Lucia whiptail lizard, hosting up to 90% of the species’ survivors.
| 9 | Santa Catalina rattlesnake |
25 kilometres off the east coast of Baja California, northwest Mexico, lies Santa Catalina Island. This is a completely uninhabited island, which looks very tempting to make a secret base on. There’s a small rocky bay, followed by endless shrubs and small, spiky cacti.
This island is a scenic oasis, with neverending blue skies and the occasional wispy cloud, but it’s perfectly possible to die here and never be seen again. Santa Catalina has 7 unique reptiles, with one being the severely endangered Santa Catalina rattlesnake (Crotalus catalinensis).
At a maximum of 73.1cm, this species is fairly small, falling well short of the western diamondback rattlesnake (maximum 233.7cm). It possesses the usual venom, but is a rare rattlesnake species to lack a rattle. The “button” that holds the rattles in place is now so devolved that the new segments simply fall off whenever the snake sheds its skin.
This rattlesnake is believed to be most closely related to the red diamond rattlesnake (Crotalus ruber). The conservation situation is severe, as Crotalus catalinensis is now listed as critically endangered by IUCN. Its home range covers a mere 40 square kilometres, and amateur collection and aggressive feral cats have only added to the pressure.
| 10 | Round Island boa |
This species differs from Cropani’s tree boa, in that it’s very close to extinction, yet everyone knows exactly where it lives. That snake pit is Round Island, Mauritius, 1200 miles off the southeast coast of Africa.
This island is purely an ecological reserve, and suffered serious damage in the 19th century as goats and rabbits were introduced. These herbivores grazed on the native fauna, munching away to their hearts’ content, but this caused catastrophic damage to the local food chain.
The resident lizards fell, as did Round Island’s native snakes. It took until 1979 to fully eradicate the goats, while the invasive rabbits were eradicated in 1986, using the same brodifacoum anticoagulant toxin used to help Antiguan racers.
By 1996, the Round Island boa (Casarea dussumieri) was estimated to number less than 250 individuals. These days, it has recovered nicely, to a far healthier 1000+. The loss would have been doubly severe, as this snake is the sole member of its genus, Casarea, meaning that an entire snake clan would have disappeared.
The Round Island boa measures just 50cm, and has a shiny black colour, while its beady eyes look similar to the sunbeam snakes of Thailand. Casarea dussumieri changes colour in a constant 24 hour cycle, shifting from dark during daytime to lighter at night.
Until 1975, the island also hosted the Round Island burrowing boa, which was part of a separate genus (Bolyeria). Sadly, this species wasn’t so lucky, as the goat and rabbit pressure forced it into official extinction (although you never know).