True love & behavioural syndromes in the bobtail lizard

Not the most glamorous of Australian species but perhaps the most lacking in tail. The bobtail (Tiliqua rugosa) is a large, long-lived species who’s males and females form unusually strong relationships. What’s their secret? I’ll reveal all.  It’s time to talk true love and behavioural syndromes.

Can’t be bothered reading? Check out the video below, or read on for more deats!

Known too, as the sleepy lizard or the shingle back. The bobtail can live for up to 50 years, and it’s only found here in Australia. While inactive for much of the year, they come out to breed during spring and early summer, and this is when their unusual relationships begin to bloom.

Bobtails are actually the best-documented example of monogamy in a lizard. Monogamous relationships (that’s when partners are exclusive with one another) are actually pretty rare in nature, and especially rare in reptiles. So the bobtails’ long-term love affair is certainly a strange occurrence!

Male and female pairs will stay together for 6 – 8 weeks up until breeding; they’ll then separate but find each other again during the following years’ breeding seasons too [this made me go awwww].  During this time it’s common to catch the male following closely behind the larger female as they walk around [as did this].

BUT! Is it true love that keeps them together?

Is love in the air? (Image: Anna Gardiner/Public Domain)

Well probably not – more likely it’s an advantage to them – possibly because couples who’re familiar with each other are more efficient at reproducing. Or maybe it’s easier to stick to their original partner, than to find a new one or fight another individual for theirs.

What’s really interesting too, is that how strong these monogamous relationships are, may actually be affected by a behavioural syndrome that exists in the male!

A behavioural syndrome is just where multiples behaviours are linked together – so in the bobtail, studies have found that males who are aggressive are also bad at being in a relationship (who’d of thought?!).

These aggressive males either don’t find a partner or when they do they spend less time with her, increasing the likelihood that she’ll mate with someone else while his back is turned  – and he won’t be the father of all her offspring.

Less aggressive males on the other hand are much more devoted partners – they prefer not to indulge in fights with other males and instead, stick close to their female, making sure that only they mate with her.

So why be aggressive at all? For a male it seems maladaptive as they’ve a lesser chance of producing offspring. However there are likely other circumstances where being aggressive works in the males favour – such as fighting other males for a better territory to forage in.

Overall though, I think there is some key relationship advice we can all take away from here. Fellas, If you’re lucky enough to have a lovely lady in your life, don’t be aggressive. Oh and be sure to follow her around. All the time. Everywhere she goes. That way, you can ensure you’ll be the father of all her children. Yay!

The Bobtail lizard – an Australian gem and another odd organism!

Keeping cool: A female bobtail that wandered through my backyard (image: Anna Gardiner/Public Domain)



Bull, C. M. (2000). Monogamy in lizards. Behavioural Processes, 51(1), 7-20.

Godfrey, S. S., Bradley, J. K., Sih, A., & Bull, C. M. (2012). Lovers and fighters in sleepy lizard land: where do aggressive males fit in a social network?. Animal Behaviour, 83(1), 209-215.

Leu, S. T., Kappeler, P. M., & Bull, C. M. (2011). The influence of refuge sharing on social behaviour in the lizard Tiliqua rugosa. Behavioral ecology and sociobiology, 65(4), 837-847.

Sih, A., Bell, A. M., Johnson, J. C., & Ziemba, R. E. (2004). Behavioral syndromes: an integrative overview. The quarterly review of biology, 79(3), 241-277.


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