Galápagos Pink Land Iguana

ReptileGalápagos Islands

Dec 4

Written By Alexander Julius Jensen

Conolophus marthae

The Galápagos pink land iguana is found only on the slopes of a single active volcano on one of the Galápagos Islands. Named for its pink scales, this land iguana was described as a distinct species in 2009 and is considered 'critically endangered' — with fewer than 200 left.

Iguanas of the Sea and Land

Clockwise from left; a marine iguana (*Amblyrhynchus cristatus*), Galápagos land iguana (*Conolophus subcristatus*), and Santa Fe land iguana (*Conolophus pallidus*).

The Galápagos Islands are storied as a haven for creatures found nowhere else in the world; an ideal laboratory for evolution to experiment and create new species. There are giant tortoises and flightless cormorants, tropical penguins and a panoply of finches, and, perhaps above all, these islands are teeming with unique iguanas, on land and at sea.

Along the volcanic rocky coasts rest colonies of sea dragons, some with bodies of dark scales, others mottled with patches of pink and green like oxidised copper. Atop their blunt snouts, they wear crowns of salt — the build-up of all the excess sea salt they "sneeze" out ¹ — and behind them stretch their long tails, compressed laterally for propelling them through the water. These marine iguanas are the only lizards in the entire world known to dive the ocean depths, foraging for algae along most coastlines of the Galápagos.

Across the arid and scrubby island interiors lumber the land iguanas. Adorned in yellow scales and growing up to 1.5 metres (4.9 ft) long, the two species — Galapagos and Santa Fe — look much alike. Both are fond of the prickly pear cactus, munching on pads and flowers with their leathery mouths, with the cactus making up some 80% of the Sante Fe iguana's diet. This latter species is restricted to the single island of Sante Fe at the centre of the archipelago. The Galápagos land iguana is more widespread; living in small colonies or solitarily — with males known to head-butt each other over territory — the species is found on Fernandina, Santa Cruz, South Plaza, Baltra, Santiago and North Seymour islands, and the largest isle of the archipelago, Isabela.

Pink Dragons

These three species were believed to comprise all the iguanas of the Galápagos. But, there was another. In the northern reaches of Isabela, on the turbulent slopes of the archipelago's largest volcano — Volcán Wolf, or Wolf Volcano ² — dwell a couple hundred pink dragons. Humans have known of their existence since 1986, but it took 23 years before these reptilian oddities were officially described as their own species — a species discovered to be among the most ancient of any on these isles.

Galápagos pink land iguanas vary in pinkness from one individual to another, but as a whole, they're quite rosy. The scales along their heads are wholly pink, with males sporting pink, ridge-like crests atop their napes. The stubby legs and dumpy bellies of some individuals are primarily pink — unsettlingly close to the colour of pale skin — but the majority have bodies streaked through with black stripes, transitioning into fully black tails. From the ends of their elongated snouts (relative to the blunt snouts of other land iguanas) to the tips of their tapered tails, these great lizards can measure up to 1.2 metres (3.9 ft) long.

The Rarest of Reptiles

A satellite photo of the 2015 Wolf Volcano eruption.

Afforded species status in 2009,³ the Galápagos pink land iguana was swiftly put onto the Red List as 'critically endangered' — one of the most endangered of all Galápagos animals. It's not hard to see why. The entire population of this species, some 200 or fewer individuals, live on the slopes of one volcano, which also happens to be the most active volcano of the entire volcanic archipelago. The first recorded eruption of the volatile Wolf Volcano was in 1797. Since then it has bellowed ash and spewed lava in 1982, 2015, and most recently in 2022. The pink iguanas are tough — living in arid habitats and subsisting mostly on cacti, like their relatives — but they aren't fireproof.

Volcanic eruptions pose the most dramatic threat, but not the only one. The pink iguanas escape the worst of the dry season by crawling down the volcano slopes into the tropical dry forests, as far down as 600 metres (1,970 ft) above sea level, but a bad drought could desiccate these already dry forests.

At the same time, the iguanas are attacked by a more active danger. The Galápagos Islands were first discovered by people in 1535. Since then, countless sailors have travelled through and made port on these islands, letting loose (intentionally and not) boatloads of pigs, goats, donkeys, dogs, cats, and rats. The latter two now imperil the pink iguana. No rat or cat in its right mind would attack an adult iguana — a large male iguana can weigh up to 75 kg (165 lbs), while a typical cat weighs just 5 kg (11 lbs) — but young iguanas and iguana eggs are still vulnerable. And each pink iguana egg is particularly valuable. For whatever reason, it seems the female pink land iguana is more sparing with her clutch size (4 - 7 eggs) than a regular land iguana (up to 25 eggs), meaning the loss of each egg hurts the species that much more. A mother pink iguana can shelter her clutch in a burrow, as most iguana species do, but a burrow isn't likely to keep out rodents who've made a living infesting our locked houses and tight-hulled ships for millennia. And even if the eggs survive to hatch, the juveniles, small and naive, crawl out into awaiting feline claws and jaws that they've simply not evolved to defend themselves against.

However, the greatest factor endangering the Galápagos pink land iguana, which exacerbates all the other threats, is simply its rarity and exclusivity. Small populations restricted to small areas are most at risk of extinction — and less than 200 iguanas, only found on one island, and then only across a total range of 25km² (15.5 mi²), are certainly at high risk. A few poor breeding seasons, perhaps coinciding with a drought or influx of predation, and the entire population, the entire species might crash. It's ultimately a numbers game; a population of 200 individuals already seems low, but the individuals that matter to the species' survival, those that make up the breeding population, are even lower. Over a large enough span of time, something bad, whether disease ⁴ or drought, is bound to happen, and when it happens, the pink land iguanas don't have the numbers to spare, they don't have a backup population of breeding individuals from which to bounce back.

The current iguana population is closely monitored by scientists and conservationists, and contact with anyone else, either Galapagueños or visitors, is strictly limited. A "head-start" programme is in the works; captive breeding and rearing, until the iguanas are around 3 or 4 years old and large enough to defend themselves from feral cats in the wild. And new research is shedding light on a great deal we've yet to learn about the species — such as a 2022 paper that described how some pink iguanas migrate upwards of 1,000 metres (3,280 ft) between different altitudes, or a 2023 paper on the "pinkness" of the pink land iguana, caused by a lack of pigment in the scales and an abundance of blood vessels just underneath. But there's still much to learn about the species before we know how to most effectively protect it. Heck, hatchlings and juveniles of the pink land iguana were only seen for the first time in 2022.

We can keep people away from the iguanas and rear young iguanas away from invasive predators, but human control only extends so far. This species' sole habitat is situated on the slopes of a temperamental volcano — and we can hardly command the primordial forces of the Earth. If the Wolf decides to bare its teeth and boil over once more, it could mean an end, in fire and brimstone, for the Galápagos pink land iguana.

Rafting Reptiles

The Galápagos Islands lie nearly 1,000 kilometres (600 miles) from mainland Ecuador. The archipelago consists of 13 main islands and many smaller ones scattered amongst them, with new islands constantly being born on its western margins. These are volcanic islands; rising from the depths as layer upon layer of molten rock settles and cools, lifted by the Nazca plate until they breach the surface as new land. They've never been connected to any mainland, but they teem with life.

The fauna of the Galápagos most closely resembles that of the nearest continent; South America. This makes sense considering that the isles were mostly populated by wayward travellers from South American shores. It's not hard to imagine how the boobies, finches, and cormorants got to the archipelago — even if the Galápagos cormorant is now flightless, its ancestors were not. But iguanas? Iguanas are strong swimmers, but not strong enough to tread 1,000 km of open ocean, and it's not just the distance, but the salt water — marine iguanas only evolved to tolerate it after reaching the Galápagos. The first iguana pioneers didn't swim, but sailed, after a fashion.

A green iguana (*Iguana iguana*) lounging in a tree.

They likely didn't cast off from South America with a will to explore. Iguanas have a habit of lounging around in trees, especially along the bank of a river or the coast — trees that can topple into the water during a heavy storm, and get swept away to sea by a current. Surely, over the spans of millions of years, there have been many rafts of reptiles-made-involuntary-sailors swept to sea that never chanced to make it to land and the reptiles perished. But the odds of a few rafts, harbouring breeding individuals (or even one pregnant female), and reaching a safe port, go from near-impossible to almost inevitable over such immense time spans — after all, the oldest islands of the Galápagos have been around for, give or take, 5 million years.

There's even evidence of such raft-colonisation in the past decade. Once there were no green iguanas on the island of Anguilla in the Caribbean, now there are. They arrived in 1995, carried some 200 miles from Guadeloupe on a bushy raft uprooted by hurricanes.

An Aldabra giant tortoise (*Aldabrachelys gigantea*) on a Seychelles beach.

The reptilian constitution is especially suited to a long sea journey. A slow metabolism eschews the need for frequent feeding, while rough-scaled skin can withstand pounding sunlight and the battering of waves. In contrast to reptiles, you rarely see native land mammals or amphibians on isolated islands; a mammal's quick metabolism would see it starve while an amphibian's porous skin wouldn't tolerate long exposure to salt water. The many island tortoises are a testament to this reptilian resistance in the face of ocean travel. They don't even require rafts; with their buoyant shells, they are their own sea vessels, stretching above the waves with long necks to periodically take in air, and able to survive for months with no food or water. That's exactly how the Galápagos are believed to have gotten their now giant tortoises. ⁵

Those tortoises are thought to have floated there from South America anywhere between 2 - 5 million years ago, coinciding with the arrival of the first iguana rafts. Whether from a single raft or several, the iguanas of the Galápagos have since diversified into the four currently known species. The exact divergences, when the species split, are still a topic of debate. The general consensus is that the marine iguanas diverged first, maybe around 8 million years ago (before the first of the Galápagos islands rose from the sea) — some sources claim a later split, around 4.5 million years ago. As for the land iguanas, the pink is by far the most ancient, with genetic analysis revealing a divergence from the other land iguanas occurring 5.7 million years ago — which would make it among the first species to evolve on these newborn isles.

A “sneezing” marine iguana — expelling salt from its nostrils.

¹ Feeding on salty marine algae while immersed in salt water, the marine iguana is liable to ingest fatal amounts of sodium. As a countermeasure, the iguana has evolved special glands that remove salt from its blood, which it then shoots out from its nostrils. Not every salty snot-rocket is a clean one, and much of it comes raining back down on the iguana's head. Over time, the build-up of salt from its own excretions forms a kind of craggly crown atop its head.

² Wolf Volcano (known as Volcán Wolf in Spanish) is an active shield volcano in the northern part of Isabela Island — the largest of the archipelago's islands. At 1,710 m (5,610 ft), its peak is the highest point in all the Galápagos.

³ You can see the paper which described the pink iguana as a new species here.

⁴ In February of 2024, it was announced that a never-before-seen herpesvirus was discovered among the pink land iguana population — the first herpesvirus documented among iguanas of the Galápagos. Collecting oral and cloacal swabs, a research team found that, out of 38 iguanas, 2 individuals (5.3%) tested positive for the virus.

Herpesviruses are common throughout the animal kingdom, including in humans, and while some cause diseases, others cause no symptoms. As of yet, there's no evidence that this possibly endemic herpesvirus in the pink land iguanas has had any impact on their health, but perhaps its discovery — which has brought increased attention to diseases within the population and will lead to routine testing in the future — might save the iguanas from potentially dangerous diseases down the line.

A phylogeny and illustrations of the extinct Malagasy and Mascarene giant tortoises.

⁵ The Galápagos giant tortoises are perhaps the most famous of the island-dwelling chelonians, not least for their size — being the largest living tortoises in the world, able to weigh upwards of 300 kg (700 lbs) — but also because they're some of the last ones left. On the other side of the world, on a few of the Seychelles Islands northeast of Madagascar, live the Aldabra giant tortoises. Not quite as massive as those of the Galápagos, they can still grow to weigh 250 kg (500 lbs). These two species demonstrate the phenomenon known as 'island gigantism'; freed from predation pressure, the tortoises were allowed to evolve to their maximum sizes. But, as far as giant tortoises go, these two are the last. The third largest tortoise species, the African spurred tortoise, doesn't even reach a max weight of 100 kg (220 lbs).

The world once harboured more lumbering, shelled giants. Two species of giant tortoise, related to the living Aldabra species, are known from Madagascar (extinct now for some 1,000 - 2,000 years). Five species of giant tortoise lived across the Mascarene Islands, which stretch east of Madagascar, including on Mauritius (of dodo fame), Réunion, and Rodrigues. Shortly after the arrival of human colonisers in the 17th and 18th centuries — who overzealously hunted the tortoises and introduced predators that ate their eggs — these giants went extinct. Megalochelys atlas, the largest tortoise ever known to exist, is also thought to have been wiped out by humans — those of a different species, however. Evidence shows staggering rates of island extinctions after the arrival of Homo erectus, and by the Early Pleistocene, this behemoth and all of its relatives were likely all but extinct.

**Where Does It Live?**

⛰️ Arid and scrubby areas and dry tropical forests.
📍 On the slopes of Wolf Volcano, in the northern part of Isabela Islands of the Galápagos Archipelago.

‘Critically Endangered’ as of 19 February, 2012.

IUCN

Size // Medium
Length // Up to 1.2 metres (3.9 ft)
Weight // Males up to 75 kg (165 lbs), females up to 35 kg (75 lbs)
Activity: Diurnal ☀️
Lifestyle: Solitary 👤
Lifespan: N/A (the Galapagos land iguana, Conolophus subcristatus, can live for up to 60 years)
Diet: Herbivore
Favorite Food: Prickly pear fruit 🌵
Class: Reptilia
Order: Squamata
Family: Iguanidae
Genus: Conolophus
Species: C. marthae

The Galápagos pink land iguana is the rarest of the four species of iguana endemic to the Galápagos Islands — the others being the Galápagos land iguana, the Sante Fe land iguana, and the marine iguana.

The species' entire range covers only 25km² (15.5 mi²) across the slopes of Volcán Wolf (Wolf Volcano), located in the northern part of Isabela — the archipelago's largest island.

200 or fewer iguanas are estimated to live on one of the most volatile of the 13 active volcanoes of the Galápagos Isles — standing at 1,710 m (5,610 ft) above sea level, Wolf Volcano is also the archipelago's highest point. Its first recorded eruption was in 1797, then in 1982, 2015, and most recently in 2022.

This iguana lives in arid scrubby habitat and subsists on cactus, crawling down the volcano slopes into tropical dry forests to escape the worst of the dry season.

This 'critically endangered' species is threatened by invasive predators, such as cats and rats. While adult iguanas are quite safe — the largest males growing to a length of 1.2 metres (3.9 ft) and a weight of 75 kg (165 lbs) — their eggs and young are vulnerable to gnawing incisors and feline claws.

Each pink iguana egg is especially valuable. For whatever reason, female pink land iguanas are sparing with their clutch sizes, producing only 4 - 7 eggs, compared to a regular Galápagos land iguana which lays up to 25 eggs at a time.

Humans have known of the Galápagos pink land iguana since 1986, but it took 23 years until it was officially described as its own species in 2009.

Genetic analysis revealed that this species diverged from the other land iguanas some 5.7 million years ago — making it among the first species to evolve on the Galápagos.