Reptiles
Monkey-tailed Skink
Corucia zebrata · also called prehensile-tailed skink, Solomon Islands skink, zebra skink
The monkey-tailed skink breaks nearly every rule of its family. Skinks are usually small, fast, ground-living insect-eaters. This one is the size of a cat, lives in the treetops, eats only leaves, gives birth to a single huge baby, and lives in a family that shares a home and looks after the young.
Overview
Corucia zebrata is endemic to the Solomon Islands, in lowland rainforest, and it is the largest skink in the world at 75–80 cm and close to a kilogram. It is fully arboreal and fully herbivorous, eating leaves, fruit, and flowers, especially the toxic pothos vine, which it digests by fermentation in an enlarged gut.
A grasping tail and a giant baby
The long tail is fully prehensile, gripping branches like a monkey’s. The skink is live-bearing and produces one enormous young — up to a third of the mother’s weight — after a six-to-eight-month pregnancy.
A social reptile
It lives in family groups called circuli that share a tree hollow and defend a territory, and adults tolerate and help protect the newborn — parental care that is rare in reptiles.
Status
Not Evaluated but declining, from decades of collection for the pet trade before CITES protection in 1992, from rainforest logging, and from local hunting. Its one-baby-at-a-time breeding makes recovery very slow.
Monkey-tailed Skink: common questions
Is the monkey-tailed skink really the biggest skink?
Yes. Skinks are one of the largest lizard families, with well over a thousand species, and most of them are small, slim-bodied, smooth-scaled ground lizards. The monkey-tailed skink is the giant of the family, reaching around 75 to 80 centimetres in total length and a body weight approaching a kilogram, far larger than the next biggest skinks such as the blue-tongued and prehensile-tailed skinks of Australia and New Guinea. It is also unusual within the family in being fully arboreal, fully herbivorous, live-bearing with a single large young, and social, so it stands apart from typical skinks in almost every way.
Why does it eat pothos leaves if they are poisonous?
The pothos, or devil's ivy, is a climbing vine whose leaves contain sharp calcium oxalate crystals and other compounds that irritate the mouth and gut of most animals, which is one reason it is left alone by browsers and thrives as an invasive plant elsewhere. The monkey-tailed skink specialises on it, and appears to tolerate the toxins, which gives it access to an abundant food source with little competition. Digesting the tough, fibrous leaves requires a fermentation chamber in the gut and a community of microbes, and a young skink acquires those microbes by eating small amounts of the droppings of adults in its group.
Why does it give birth to only one baby?
The monkey-tailed skink has traded quantity for quality. Rather than laying a clutch of eggs or bearing a litter of small young, the female carries a single embryo for six to eight months and gives birth to an animal that is already a substantial fraction of her own size, fully formed, mobile, and able to feed itself and climb almost immediately. That newborn then benefits from being born into a family group where adults and older siblings tolerate it and help keep predators away. The strategy suits a large, slow, long-lived canopy animal with few predators as an adult, but it means a female produces very few offspring in a lifetime, which is why the species recovers so slowly from losses.
Can you keep a monkey-tailed skink as a pet?
It is kept by experienced reptile keepers, and captive breeding has improved since wild collection was restricted, but it is a demanding and long-term animal, living 25 years or more. It needs a tall, planted, humid enclosure with plenty of climbing branches and a hollow to hide in, a varied plant-based diet, and, ideally, to be kept as a compatible pair or small group rather than alone, since it is naturally social. It is easily stressed by handling and by being housed with an incompatible individual. Any animal acquired should be captive-bred with paperwork, both for legal reasons and because wild populations cannot sustain collection.