The Scaly Monogamist – Shingleback Lizard

The shingleback lizard (Tiliqua rugosa) is most at home in the rugged, dry plains and shrublands of southern and western Australia. It is a large species of blue-tongued skink that can reach a foot in length. This lizard may not look like much with its dull, armored skin and stubby tail, but it forms a bond that is quite unusual in the world of reptiles, especially among lizards.

The very head-like tail of the shingleback lizard:

Unlike almost all other lizards, the shingleback is socially monogamous. When a male and female form a pair bond, they will maintain that bond for the rest of their lives. During the breeding season, they come together and stay with each other for a couple of months and then mate. Once the female is pregnant, the two will separate, but they will reunite again the next year. These lizards have been known to remain together for over 10 years or more and may sometimes spend time together outside of breeding season as well. Shinglebacks are slow moving and often bask in the sun on or near roadways. Unfortunately, some of them get hit and killed by cars because they aren’t able to move fast enough to get out of the way. This has revealed that even after the death of one lizard, its mate continues to keep that bond. A shingleback that has lost its mate by the roadside may stay with it for several days, gently nudging it and licking it. This may be one of the closest things to grieving that has been observed in reptiles, and it is really quite touching.

A mated pair of shinglebacks:

Though they have no defenses against cars, shinglebacks do have several ways of dealing with natural predators. One defense adaptation is their tails. Short, stumpy, and rounded, the tail looks almost exactly like the lizard’s head and may trick a predator into attacking this much less crucial part of its body, or just confuse it enough to make it leave. If this fails, they can use the threat display that is famous within the Tiliqua genus – the blue tongue. When threatened, a shingleback may raise its head, hiss, and open its mouth to reveal its blue-black tongue to scare off a predator. This startling display is followed up with a painful bite if the message isn’t clear enough. The last option for this lizard is to flatten itself to the ground and continue hissing.

Blue tongue display:8604570652_36110ea7f0_b

Most of the time, adult shinglebacks are left alone by predators and are allowed to go about their business, such as reproducing, in peace. Shortly after mating when a female shingleback parts ways with her partner, she will produce one to four large babies. This skink is ovoviviparous, which means she gives birth to live young without connection to a placenta. The eggs stay in her body and she incubates them by collecting thermal energy from basking in the sun. When they are mature enough and have hatched, she gives birth. All the babies together can weigh up to a third of her body weight, which is the equivalent of a human mother giving birth to a three year old child. After birth, the new shinglebacks will stay with their mother for several months until they are independent enough to fend for themselves. They won’t go too far, though, as families of shinglebacks tend to stay near each other within the area.

Baby shingleback born at Lincoln Park Zoo, Chicago in 2009:

People generally think of reptiles as cold, unfeeling, and primitive. This quiet, desert skink, and many other reptiles, prove that there is more to them than just pure, unthinking instinct. They can be gentle, sophisticated, and tender, showing many of the characteristics which we find so endearing in our warm blooded relatives. So go out and show reptiles a little love. Some of them just might be able to return it in their own, scaly way.

References:
1. Loch, Thomas. “Tiliqua rugosa (Shingleback Lizard)”. Animal Diversity Web. University of Michigan Museum of Zoology, 17 Feb. 2009 Web. 24 June 2015. < http://animaldiversity.org/accounts/Tiliqua_rugosa/&gt;

2. Bull, C. Michael, Steven JB Cooper, and Ben C. Baghurst. “Social monogamy and extra-pair fertilization in an Australian lizard, Tiliqua rugosa.” Behavioral Ecology and Sociobiology 44.1 (1998): 63-72.

3. “Shingleback Lizard.” Australian Museum. Australian Museum, 16 Dec. 2013. Web. 24 June 2015. <http://australianmuseum.net.au/shingleback-lizard&gt;.

4. Bull, C. Michael. “Monogamy in lizards.” Behavioural Processes 51.1 (2000): 7-20.

Photo and Video Links:
1. https://upload.wikimedia.org/wikipedia/commons/1/19/Shingleback_Skink_at_Sydney_Wildlife_World.jpg

2. http://website.lineone.net/~lilacdragon/LizardsOfOz/6-%20South%20Australia%20-%20Flinders%20and%20Mt%20Remarkable/slides/142-Shinglebacks%20-%20Tiliqua%20rugosa.html

3. https://flic.kr/p/e7mF5q

4. https://www.youtube.com/watch?v=aPZiAiUYS8o

5. http://voices.nationalgeographic.com/files/2009/09/shingleback-skink-picture.jpg

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