How Often Do Anoles Lose Their Tails In Intraspecific Fights?

Male A. pogus fighting. Photo from

Recently, our lab group was discussing what can be inferred from calculating tail loss rates in anole populations. It was pointed out that tail loss doesn’t necessarily result from predators and that, in fact, males may bite off the tails of other males in fights,  and the victor or vanquished may even eat the tail. Someone pointed out that the older literature certainly pointed this out with examples*, but we haven’t seen much of this in more recent literature. So, we then asked, has anyone ever actually seen a tail lost in a fight? No one had. I then got online to look for photos. I could find plenty of males fighting, usually locking jaws or sometimes biting the body or a limb, but I found no photos of an anole biting another’s tail, much less biting off a tail. So, I ask you, fair AA reader, have you ever seen this? Can you provide a photo?

*By earlier literature, we were thinking 1960’s and 1970’s, but here’s a quote from the 1870’s, referring to A. cristatellus. Can you name the author? “During the spring and early part of the summer, two adult males rarely meet without a contest. On first seeing one another, they nod their heads up and down three or four times, and at the same time expanding the frill or pouch beneath the throat; their eyes glisten with rage, and after waving their tails from side to side for a few seconds, as if to gather energy, they dart at each other furiously, rolling over and over, and holding firmly with their teeth. The conflict generally ends in one of the combatants losing his tail, which is often devoured by the victor.”


About Jonathan Losos

Professor and Curator of Herpetology at the Museum of Comparative Zoology at Harvard University. I've spent my entire professional career studying anoles and have discovered that the more I learn about anoles, the more I realize I don't know.

8 thoughts on “How Often Do Anoles Lose Their Tails In Intraspecific Fights?

  1. I’m not sure autotomy through intraspecific fighting occurs that often, though it’s a subject worth investigating. I have seen Trachylepis skinks in S. Africa curled together biting at each others tails and autotomy never seems to occur through that. Biting the tail off a rival would be adaptive I would have thought – for Iberolacerta monticola in Spain, males missing tails end up with smaller territories and less access to females. I have had a large male A. cristatellus cause autotomy of about a third of the tail of small female, but that was when they were in a plastic tub being transported – they were only in there for about 10 minutes as well.

  2. I’ve clocked up hundreds of hours of observation on most Jamaican and Puerto Rican Anolis species. I’ve happened across several intense fights among males, and recorded some of those on video, but I’ve never seen a lizard drop its tail as a consequence of a fight — and I’ve seen some pretty horrendous anole fights! Grace Charles compiled some statistics on the proportion of several Puerto Rican species that had missing or regenerated tails, and it was a fair amount (I’d have to look up the figures to know the precise proportion, but from memory it was something like 25-30% of males). I should also add, though, that my observations of predation events have been very rare (two or three; all on Puerto Rico), but that isn’t too surprising given the presence of a human observer. That is, while it’s “common” to see fights among males because anoles generally habituate to a human observer very quickly, my feeling is that the presence of a human observer would scare off most potential predators…

    1. I agree with Terry on this. I have not collected the countless hours of rigorous data on anole behavior that he has; but I have certainly observed many A. cristatellus in the field (including many intraspecific interactions) and have never observed tail loss to be the result. Males will sometimes lose their tails if transported in the same bag, though.

      1. The cristatellus male I observed definitely removed the female’s tail as the plastic was pretty clear, but that was more analagous to a predatory event: they were both pretty stressed, having just been caught. There is a paper I can’t remember who by that notes that a Gallotia sp. was observed to predate on smaller conspecifics, targeting the tail and eating it once autotomised.

  3. Stan Fox’s work from the 1980s showed strong social costs to tail autotomy in side-blotched lizards, but the losses were apparently not due to loss during a fight. I’ve never seen tail loss during a fight in any lizard species I’ve observed. Incidentally, Stan’s work from the 1980s and 1990s discusses a lot of the caveats associated with using tail break/loss frequencies as a measure of “predation pressure” in a population.

  4. I’ve been observing South sand South West Florida lizards since the 1960’s and cannot recall ever seeing a tail lost in a fight. I asked my mom who taught me to observe and love nature and she cannot remember seeing a tail lost in a fight.
    I have seen the local cardinal, Cardinalis cardinalis remove a tail while trying to pull Anoles out of our Windows more than once. I suspect they want the entire lizard but settle for the tail. Have also seen other birds checking the hiding spots in Windows.

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