New Caledonia Research Expedition
Crested geckos and their island-dwelling cousins have become a popular sight in the UK pet trade. Their striking appearance, docile nature and manageable diet requirements make them an ideal first reptile.
Previously, housing an arboreal gecko from a remote tropical island in the pacific would be considered a challenge, but with scientific breakthroughs igniting an exciting field of product development, recreating New Caledonia in our living rooms has never been so accessible.
Island Paradise
Located between Australia and Fiji in the Southwest Pacific Ocean, New Caledonia is exceptionally remote. As a French colony, the 280,000 residents of New Caledonia are considered French citizens and vote for the President of France. The archipelago is broken into three separate provinces across a handful of islands. These islands include Grande Terre (the largest island), The Loyalty Islands, the Chesterfield Islands, the Belep archipelago and the Isle of Pines.
New Caledonia has some of the richest biodiversity per square km in the world. Despite being less tropical than other island nations in the region, New Caledonia still has two distinct seasons. The ‘dry’ runs from May until October, whereas the ‘wet’ runs from November to April. During the height of the wet season, sunlight can drop to just 5 hours per day and average between 18°C-22°C, whereas the dry season is much closer to around 8 hours per day and averages between 24°C – 28°C. Of course, this will vary across locations and altitudes.
Gecko Haven
Islands are often home to some of the most unique animals on the planet. Just like Madagascar’s rich spectrum of day geckos, New Caledonia is home to its own group of geckos with striking appearances. From the mossy prehensile-tailed gecko with its impeccable camouflage, to the cryptic Bavayia genus and its spectrum of recently discovered species, New Caledonia’s herpetofauna is obscure and mysterious.
The slightly less mysterious, but equally obscure Rhacodactylus genus makes up some of the oddest-looking lizards in the world. The gargoyle gecko (R. auriculatus) and the New Caledonia giant gecko (R. leachinaus) are both exceedingly popular species within the pet trade. However, after being reclassified from Rhacodactylus ciliatus to Correlophus ciliatus, the crested gecko is truly in a league of its own. Now a popular sight in pet shops across the globe, this gecko exhibits a whole list of traits desirable in a pet lizard.
Here Comes the Sun
Exotic pet owners, from reptile keepers to parrot enthusiasts know the importance of UVB for good animal health. However, understanding the requirements of each individual species presents itself as an even greater challenge. Therefore, the industry is currently building on the ‘Ferguson Zones’ model which relates a reptile’s basking behaviour to the correct level of UVB output from artificial lighting. This model allows crepuscular animals such as the crested, gargoyle and New Caledonia giant geckos to receive less than 1 UVI (Ferguson Zone 1), simulating the levels they would be typically exposed to in the wild.
Peter Blake, Marketing Executive at Reptile Systems has been in herpetoculture for 40 years and believes the Ferguson Zones concept will encourage keepers to provide beneficial UVB for crepuscular species that are sometimes neglected from the wider conversation. He explained: “any animal that lives outside will benefit from the mimicry of natural sunlight. That animal’s relationship to this may just be anything from synchronising its circadian rhythm to full dependency on the heat, light and ultraviolet the sun provides. Even animals that live at the deepest depths are indirectly affected by sunlight in some way. UV also has an impact on the way we keep and raise insects and improvements can be found in the calcium values just by keeping them under good quality light for a few weeks before feeding them to an animal. With some good quality gut-loading and some UV lighting, the insects can be much more nutritious.”
Land of the Giants
The New Caledonia giant gecko is the largest gecko in the world. With males reaching 36cm in length and weighing between 227 and 350 grams, these giants can be distinguished from their slightly thinner female counterparts. Although not as popular as the crested geckos, ‘leachies’ have been in the hobby for a number of years now. Nick explains: “the leachianus are very impressive animals. They suffer from the same disadvantage of cresties in that they’re nocturnal but they’re lovely animals. The island form that many of them are, used to be Rhacodactylus leachianus henkeli but the island forms and the mainland forms are all the same species now. Mine, the island forms are very tame! In fact, I’ve never been bitten by the leachianus whereas it was a daily occurrence with the number of crested geckos I was handling. Again, they’re nowhere near as prolific as the crested geckos. They require pairing up and they either take to each other or they don’t, but the old individuals are the best breeders.”
Leachies can make very appealing pets for those with enough space to house them appropriately. Their easy care and stunning appearance make them suitable for reptile owners looking for a larger pet. While we advise against handling any reptile too often, cresties are much more tolerant than leachies. Those looking for an impressive, easy to care for animal can find great joy in owning a New Caledonia giant gecko, but crested geckos will inevitably be the better choice for first-time keepers or young owners.
Going Gothic
The gargoyle or “knob-headed” gecko, gets its name from its large, bumpy cranium. Unlike the crested gecko, this species is reasonably variable in the wild. Wild colouration usually mimics moss and bark, so animals are typically various shades of green, brown and grey. However, some individuals will have specs of red and orange as well as distinct dorsal and lateral stripes amongst the mossy banding that is presented by wild-type geckos. Most of the species’ bright colouration lies around the animal’s head or in dorsal and lateral stripes that provide a great indicator of this species’ natural habitat.
The gargoyle gecko is one of the most widespread geckos in New Caledonia. However, they are most frequently found in maquis shrubland and forest edges. Their stripes help them seamlessly blend into thin branches, as well as tree bark. Gargoyle geckos can also be found in small bushes and isolated trees and are often spotted crossing the road and exhibiting terrestrial behaviors. The maquis’ habitats occupied by gargoyle geckos are very different to the forest understory occupied by crested geckos. Both species have evolved to inhabit completely different ecological niches to avoid conspecific competition. Although in some regions such as the Blue River Provincial Park, the two species can be found relatively close to one another, the habitat that they occupy is strikingly different.
Fruit Caledonia
Crested geckos are naturally omnivorous, feeding on a range of fruits, insects and even other reptiles. A study conducted on wild crested geckos in 2007 by French researchers led by Herve Saint-Dizier in New Caledonia found that the stomach contents of wild animals contained the following matter:
Plants: Pollen aggregates 10.3% Soft seeds 1.8% Berries 11.7% Fruit juices 7.52%
Insects: 49.6% (Coleoptera 9.45% Caterpillars and butterflies 7.52% Diptera 3.12% Roaches 6.2% Orthoptera (crickets and locusts) 21.6%
Vertebrates: Smaller lizards (including their own young) 11.4% Other vertebrate prey 8.68% (of which young rodents: 6.42%)
Providing an omnivorous diet in captivity can be extremely rewarding as a keeper. Many tortoise and bearded dragon owners will take great pride in the meals they prepare for their animals and crestie owners are no different. Luckily, simulating the pollen aggregates and fruit juices of the unique New Caledonian flora has become much easier with the popularity of premixed diets.
Recreating the Wild
New Caledonias flora has the highest levels of endemism in the world, with three quarters of the flora on these islands found nowhere else on the planet. As such, replicating a perfect slice of New Caledonia is difficult, but tropical ferns provide a great starting point. Crested birds nest ferns (Asplenium antiquum) have broad leaves and provide great climbing opportunities when planted high in the terrarium. Rabbits foot ferns (Davallia .sp) also create a brilliant Jurassic look and can be planted into the sides of a bioactive enclosure to provide hiding space.
Recreating the tropical forest environments of New Caledonia is extremely straightforward with new products in the hobby. Of course, a bioactive set up can be extremely rewarding and require a different approach, but species-specific products have surfaced in the market in recent years. Jamie Girling is Product Development Specialist at ProRep and created Crestie Life, a substrate designed specifically for crested geckos. He told Exotics Keeper Magazine “Humidity is really important for crested geckos so designing a substrate that releases humidity gradually was crucial. Egg laying is also important for animals that would typically dig to lay their eggs. If an animal can’t find a suitable place to lay their eggs they can become egg-bound, which is potentially problematic for the animal. But really, Crestie Life came about to move people away from that standard of beech chip or bark chip which would never occur naturally in their environment. Also, people won’t always want to do a Bioactive set up. Obviously, it costs a lot more to create a more complex environment, so the Life series basically replicates some key environmental factors at a lower cost. What’s key for crested geckos is high humidity and Crestie Life was designed with different sized particles to slowly release that moisture over time, contributing to a steady humidity.”
In the wild, many of the New Caledonian gecko species would rarely visit the forest floor. However, our captive environments create new challenges and giving the animals as much space and environmental enrichment as possible is key to overcoming these. Creating a drainage layer with a small reservoir of water beneath will provide a steadier humidity level than spraying the enclosure.
Next Caledonia
Between 2013 and 2019, New Caledonia saw a 17.5% increase in tourism which made 2019 the busiest year on record. What that means for the flora and fauna is unknown. But, with ecotourism taking centre stage in the travel industry in recent years and New Caledonia’s biodiversity already internationally recognised, the wild geckos of this island should hopefully find some security. As for our much-loved pets in the private sector, the future seems very bright. Captive bred animals are abundant, meaning responsibly sourced pets are never an issue. Advancements in product development are making husbandry much easier and although we might see competition for top spot in the pet trade, the crested, gargoyle and New Caledonia giant geckos will be with us for many years to come.