Cape Verde giant skink facts for kids
Quick facts for kids Cape Verde giant skink |
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| Illustration, 1885 | |
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Chioninia
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coctei
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The Cape Verde giant skink (Chioninia coctei) was a very large lizard. People also called it Bibron's skink or Cocteau's skink. In Cape Verde, it was known as lagarto. This amazing animal lived only on some of the Barlavento Islands in Cape Verde. Sadly, it became extinct in the 20th century.
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Understanding the Cape Verde Giant Skink's Name
The Cape Verde giant skink got its first scientific name, Euprepes coctei, in 1839. Two French zoologists, André Marie Constant Duméril and Gabriel Bibron, named it. The name coctei honors a French doctor and zoologist, Jean-Théodore Cocteau.
How Scientists Studied the Skink
The first specimen studied was a preserved lizard in a museum in Paris. It was one of five collected in 1784. These lizards were taken from Ilhéu Branco to Lisbon. Later, they were taken by the Napoleonic Army in 1808. Because of this, the scientists first thought the skink came from "the coast of Africa".
Rediscovery and New Names
The skink was "rediscovered" in 1873 by a doctor from Cape Verde. A Portuguese zoologist, José Vicente Barbosa du Bocage, then gave it a new genus name, Macroscincus. This name means "large skink".
Modern Science and Family Tree
In 2001, scientists used Mitochondrial DNA to study the skink's family. They found that Macroscincus belonged to a group of Cape Verdean skinks. These skinks were once grouped into a large genus called Mabuya. This suggested they all came from West Africa a long time ago. They spread to Cape Verde and then developed into many different species. By 2016, scientists placed the Cape Verdean skinks into the genus Chioninia. They also found that Trachylepis from Africa was its closest relative.
What Did the Cape Verde Giant Skink Look Like?
The Cape Verde giant skink was much larger and stronger than other skinks. Adult skinks could grow to about 32 centimeters (12.6 inches) long from their snout to their tail base. Their tail was less than half the length of their body.
Tail and Movement
Some people thought its tail could grasp things, like a monkey's tail. This would have helped it climb trees. This was surprising because the islands where it lived were often dry and had few trees. However, other scientists noted that skinks could drop their tails if in danger. This is called autotomy. A tail that can be dropped usually isn't used for grasping. Its long toes suggest it might have climbed low trees.
Teeth and Scales
The skink had special teeth that were flat and had many points. These teeth were good for chewing. Its body had small, ridged scales. These scales were in over a hundred rows around its middle. However, its bony armor under the skin was not as strong as in some other skinks.
Unique Features and Colors
A special feature was a clear "window" on its lower eyelid. This was unique among skinks. The skink came in three main colors: grey, yellow, and a mix of both. It had dark spots and freckles on a yellow-green-grey background. Its belly was lighter and had fewer freckles.
Differences Between Males and Females
Male skinks grew to their full size faster than females. Males also had bigger heads, stronger jaws, and longer back legs. Older males had thick, hanging skin under their chin. This is called a dewlap and is unusual for skinks. It might have been used to show off or defend their territory.
Where Did the Giant Skink Live?
Scientists found old bones of the Cape Verde giant skink on the northwestern islands. These include São Vicente, Santa Luzia, and the small islets of Branco and Raso. These islands were once connected as one large island during colder times. Some local fishermen also said they saw giant skinks on São Nicolau island. However, this has not been proven. São Nicolau was not connected to the other islands by land.
How Did the Giant Skink Live?
We don't know much about the daily life of the Cape Verde giant skink. This is because it became extinct before scientists could study its behavior. However, it shared some traits with other lizards. For example, the African striped skink also lives in low trees. Another large, plant-eating skink, Chioninia vaillanti, lives on other Cape Verde islands.
Possible Adaptations
The clear "window" on its lower eyelid might have helped it see predators. It might have used this while sleeping in low trees with its eyes closed. If so, the predators it watched out for might have died out long before the skink did. This need for light suggests the skink was active during dawn or dusk. It probably slept during the day. Barn owls are known to have eaten skinks both before and after humans arrived.
What Did They Eat?
The Cape Verde giant skink had a long digestive system and special teeth. This suggests it mostly ate plants. In captivity, some skinks lived for years on a diet of fruit and plants. One skink was even seen eating a bird. On Branco and Raso, which had little plant life, the skinks adapted. They lived among large colonies of shearwaters and petrels. They ate bird throw-up, droppings, dead animals, eggs, and baby birds. Scientists often find skink and seabird bones mixed together.
How Did They Reproduce?
Some preserved skinks show signs of giving birth to live young. This is called viviparity. However, one female in captivity laid seven white eggs over 15 days in 1891. These eggs were about 1.5 inches (3.8 cm) wide. It's possible that this species could do both. Some other skinks are known to switch between laying eggs and giving birth to live young.
Temperament and Lifespan
The skinks were very calm and gentle when kept by humans. Like many island reptiles, they likely lived a long time and reproduced slowly.
Why Did the Cape Verde Giant Skink Disappear?
The "Mindelo" island, where the skinks lived, broke apart as sea levels rose. This happened at the end of the Ice Age. This split the skink's population into smaller groups. The climate also became drier, changing forests into dry shrublands.
Human Impact and Introduced Animals
When the Portuguese arrived in 1461, they cut down trees for wood. They also brought goats, which ate the remaining plants. They introduced mice, cats, and dogs. These animals attacked the seabird colonies, which the skinks relied on for food. People also ate skinks, but not as often as seabirds. Old owl pellets (regurgitated food) from Santa Luzia show skink bones before 1673. After that, skink bones are rare, meaning they were already uncommon.
Last Strongholds and Over-Collecting
Giant skinks lasted longer on Branco and Raso. These islets were not settled by humans and had no introduced mammals. In 1783, people used skink skins from Branco to make shoes. Their fat was also used as medicine. There's a story that during a famine around 1833, prisoners were left on Branco. They supposedly survived by eating fish and skinks. However, Branco has no fresh water, so this story is questioned.
Demand for Specimens
The skink's rarity, large size, and calm nature made it popular for museums and collectors in Europe. In 1890, wildlife traders captured up to 200 skinks from Branco. They sold them in England, Germany, and Austria. An Italian scientist, Mario Giacinto Peracca, bought 40 skinks. He kept them for years and learned important things about their reproduction and diet.
Attempts to Save Them
By 1896, people worried the skink was becoming extinct. A museum official was asked to stop importing them. In 1898, one explorer noted the skink was still common in Raso but very rare in Branco. Another explorer found no skinks in Branco that same year. Yet, collecting continued in Raso.
Final Decline
Despite efforts, no breeding colony was successfully started in captivity. By the early 1900s, it was clear the skink was close to extinction. In 1915, an official reported that fishermen had released dogs on Raso. These dogs quickly killed all the skinks there. Some skinks survived in zoos in Germany and Austria-Hungary through World War I. But the species was declared extinct in 1940.
Later Sightings and Searches
Someone reportedly saw an individual skink on Branco in 1985. However, expeditions in the 1990s found none. The IUCN red list officially listed it as extinct in 1996. In 2005, a young skink jaw was supposedly found in cat droppings on Santa Luzia. But a survey of the island in 2006 found no living animals.
