There’s a lot to be jealous about when it comes to lizards. Some can climb walls, some are ridiculously good at hide and seek, they’ve got tails, and – perhaps coolest of all – many can drop and regenerate said tails when in a bind. 

Yes, the regenerative skills of lizards are well known, but is there a limit to how many times they can pull off this defensive magic trick? And why do you sometimes see lizards with more than one tail?

How many times can a lizard regrow its tail?

It's a question we put to Dr Damian Lettoof, an adjunct research fellow at the School of Molecular and Life Sciences at Curtin University. Turns out, when that first bony tail pops off, it’s never the same again, but that doesn’t stop the lizard from sprouting more – and sometimes multiple – tails.

Technically there is no limit to how many additional tails can grow from an existing tail

Dr Damian Lettoof

“Lizards' tails are designed to regenerate when the tail vertebrae breaks along a specific plane, triggering a replacement growth of a rigid cartilage rod,” Lettoof told IFLScience. “A break from this rod is less likely to trigger a regeneration event, although we have plenty of evidence of this happening with regen-on-regen tails, and additional tail sprouts (e.g., bifurcation).”

“The mechanism of how this happens hasn’t been studied in a long time, but there is evidence of when the glial membrane that lines the spinal cord is disrupted from damage the regeneration process starts—although this is much less likely to happen because the vertebrae break much more easily when a lizard is trying to escape a predator than a hard cartilage rod. It also means if the original tail remains partially attached extra tails can grow.”

“So, although most individual lizards can regrow their tail as many times as how much original vertebrae remains, technically there is no limit to how many additional tails can grow from an existing tail – if the conditions are right…”

Lizards with lots of tails

That fancy word "bifurcation" that he dropped in there is a curious feature of lizards that, until recently, was strangely underreported given it has turned out to be quite common. That's something Professor of Biology Dr Hinrich Kaiser of Victor Valley College discovered during a review of the available data on lizards with lots of tails. 

Furcation means something that is branched, as in the fork-tailed anole at the top of this article, but sometimes lizards have taken the suggested number of tails with a massive pinch of salt. In fact, Kaiser told IFLScience that there was even a report of a lizard sprouting as many as nine of them.

It was almost inconceivable that something that we began to recognize as pretty common was SO underreported

Prof Hinrich Kaiser

A paper co-authored by Kaiser and Timothy Baum identified furcations in 250 lizard species from 25 families. The majority of those were bifid, meaning two-tailers – but in 13 percent of species, greater numbers of tails were seen. Given the surge in reports and press coverage since two papers on the topic were published in 2020 (Barr et al., Grimm-Seyfahrt & Henle) they suggest that multiple tails in lizards aren’t a particularly rare or unusual occurrence, and that citizen science may offer a great opportunity to better understand furcation occurrence.

“When we began with just the lizard from Tim Baum's backyard, we had no idea about the breadth of this phenomenon,” Kaiser told IFLScience. “It was almost inconceivable that something that we began to recognize as pretty common was SO underreported. Publication of this paper has resulted in tremendous ‘citizen science’ echo, with all kinds of colleagues and people on social media sending in observations.”

So, keep your eyes peeled!

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.