What's that on the leaf?

What's that on the leaf?

Hong Kong's 10 species of skinks look like snakes with legs, yet are part of the lizard family


Hong Kong is home to 10 different species of skink, including the blue-tailed skink (top) and long-tailed skink (bottom).
Hong Kong is home to 10 different species of skink, including the blue-tailed skink (top) and long-tailed skink (bottom).
Photos: University of Hong Kong, School of Biological Sciences
If you a walking in the countryside and see a reptile with smooth, shiny scales like a snake, but also with four legs like a lizard - don't fret. It is no monster hybrid: it is a skink.

With 600 species, skinks form one of the two largest lizard families. Hong Kong is home to 10 different species. Our skinks are secretive land animals, which by day spend much of their time foraging under leaves. Only Chinese waterside skinks hunt after dark.

Smaller species eat termites and beetles; larger ones feed on snails, grasshoppers and earthworms.

The most common species are Chinese skinks and long-tailed skinks. Their long, slender cylindrical bodies and cone-shaped heads are frequently colourfully striped; some species are banded, spotted, or uniformly coloured.

Skinks are highly adaptable: they can thrive in tropical forests in the Amazon region of South America and also arid areas in the Australian outback.

Billy Hau Chi-hang, a wildlife expert at the University of Hong Kong, says they can cope with different conditions because they are cold-blooded. "Skinks can change their body temperature according to the weather," he says.

Hong Kong's skinks are smaller in size than their cousins abroad. They usually measure from 20cm to 40cm long, with their tapering tails forming up to two thirds of their body length. Their tails, which they use for balance, can be shed easily if grabbed by a predator. The tail can also grow back.

Some skinks have reduced limbs or are even legless like snakes, but their body structure remains close to that of lizards. The difference lies in their movement, Hau says.

"Snakes can slither swiftly through grass thanks to the use of their well-developed muscles and scales," he says.

"But legless lizards still count on their spine to be able to move."

Skinks without limbs are more suited to habitats with thick grass; they make less noise while hunting.

Most skinks have red blood, but a few in the genus Prasinohaema have green blood caused by a build-up of bile waste, called biliverdin.

Skinks normally lay eggs, but some in Australia have evolved to give birth to live young.

"If there is a lot of predatory pressure on their eggs, the survival rate of their species will be low," Hau says.

"That's why some species abandon egg-laying in favour of live birth."



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