I am very fond of skinks and it was a pleasure to see this beautiful creature on a number of occasions in Bali recently. They are however, rather shy and I only managed to get some decent photographs in one location: the Bali Mangrove forest walk. These lizards are kept as pets by some people, so it is not hard to understand why wild ones are a little leery of human beings. These lizards have also been moved around S E Asia by humans in the past, either knowingly or unwittingly in goods and transport.
The Many-lined Sun skink, Eutropis multifasciata – which was formerly known as Mabuya multifasciata – is a medium-sized, lizard, which gives birth to live young (vivipary). There can be between two to seven baby skinks in a litter (1). The Many-lined sun skink has a very wide tropical distribution, ranging from southern China west to India, south to Malaysia, Singapore, Indonesia, the Philippines, and New Guinea (2). Here is a picture of one I took in Chiang Dao, in northern Thailand (below).
The name ‘many lined’ refers to the dark scale lines (five to seven) which run longitudinally down the dorsal (back) side of the body. The Balinese skink clearly has the same pattern, as can be seen in the following photograph of one climbing up a curb to a path in the Bali Mangrove Forest (Mangrove Forest Nusa Lembonga).
The Many-lined Sun skink is a variable species and the colour of the flanks can vary from olive-brown to reddish-orange (3). The throat colour is also reportedly variable, from white to yellow (3). These skinks have the endearing habit of lifting one or two limbs off the ground, presumably to cool down. The same skink has raised its left hind-limb in the above photograph, but a few moments later raised its left fore-limb for a few seconds on top of the wall (below).
Sun skinks feed on invertebrates such as spiders, insect larvae, snails, grasshoppers and crickets (4). I’m not sure if this one was a male or female, but males are slightly larger than females and have larger heads. The Bali skink is very characteristic with its lovely yellow scales running along its flank. Other varieties of this species have a more orange colour, but all the ones I saw on Bali were yellow.
It’s tempting to think that something that looks so different is a different species, but that is not always the case if varieties can interbreed. Populations on islands such as Bali have become genetically isolated and are reportedly somewhat different from mainland populations, but not by very much. Examples of the different varieties are shown on Link 3. The Balinese skink was first named as a separate subspecies by a German herpetologist called Robert Mertens in about 1930 (5).
Despite the rather obvious differences between some varieties of this widespread species, recent research suggests that the Bali skink is not sufficiently different to qualify as a separate subspecies. For example, it was only about 1% different in terms of its mitochondrial RNA, from E. multifasciata populations on nearby Java (6). Presumably they could interbreed, but perhaps this has never been tested! It’s a pity that it is not a separate subspecies in a way, as the Bali skink looks so different, but the yellow coloured scales on the flanks is probably a superficial character and may not amount too much. That said, I bet the skinks know which ones come from Bali and which ones come from other islands!
The Bali skinks were further inland from the actual mangroves where another skink – Mangrove Skink (Emoia atrocostata) – was very abundant.
Links and references
- Sexual dimorphism and female reproduction in the many-lined sun skink (Mabuya multifasciata) from China. Journal of Herpetology, 40(3), 351-357.
- SUN, Y., Yang, J., & Ji, X. (2009). Do not Compensate for the Costs of Tail Loss by Increasing Feeding Rate or Digestive Efficiency. JOURNAL OF EXPERIMENTAL ZOOLOGY, 311, 125-133.
- Ngo, C. D., Ngo, B. V., Truong, P. B., & Duong, L. D. (2014). Sexual size dimorphism and feeding ecology of Eutropis multifasciata (Reptilia: Squamata: Scincidae) in the Central Highlands of Vietnam. Herpetol Conserv Biol, 9, 322-333.
- Mertens, R. (1930): Die Amphibien und Reptilien der Inseln
Bali, Lombok, Sumbawa und Flores. Abh. Senckenberg.
Naturf. Gesell. 42: 115–344.
- Mausfeld, P., & Schmitz, A. (2003). Molecular phylogeography, intraspecific variation and speciation of the Asian scincid lizard genus Eutropis Fitzinger, 1843 (Squamata: Reptilia: Scincidae): taxonomic and biogeographic implications. Organisms diversity & evolution, 3(3), 161-171.