Guerrilla Warfare by Female Anoles?

Have any of you witnessed a female anole biting a male anole without provocation and without preceding dewlap displays or bobbing?  In my 20+ years experience with anole husbandry, I have never observed the following behavior by a female Anolis carolinensis.

To make room for a new baby A. carolinensis, this two-year-old gravid female was moved from her solitary home in a 20 gallon aquarium to a 40 gallon aquarium with a roommate.  Her roommate was not new to her as she had previously lived peacefully (and copulated) with this old male A. carolinensis.  Immediately, I noticed bite marks on the female’s head which I assumed were a result of the old male “missing” her neck during breeding attempts (he is pretty old at 7 years of age after all).  What drew my attention; however, were the bite marks on the male’s head, neck, and leg.  Later, I observed this female biting while bobbing and pulling on the neck of the male.  Even after I moved her to another aquarium to live with a different male, I found similar wounds on his neck, leg, and tail.  Now she lives alone again and I thought this would end the attacks but today, while she was out of her aquarium, she ambushed another male, firmly biting his neck, and did not release until I intervened.  I captured a portion of her attack in the video below:

As you can see, she is clearly stressed as evidenced by the black patches behind her eyes and she seems intent on causing as much damage as possible to the male.  I’m interested to know if others have observed this type of “Guerrilla warfare” by female anoles.  Any insight into its etiology or purpose?

Natural History Observations

About Allison DeVan

I received my Ph.D. in Vascular Physiology from The University of Texas at Austin in 2009. I am currently a postdoctoral fellow/research faculty at the University of Colorado-Boulder in the Integrative Physiology of Aging Laboratory. My research focuses on the effects of aging, exercise, nutraceuticals and disease on endothelial function and large elastic artery stiffness in humans. Although I do not formally research Anolis, I have bred and kept Anolis carolinensis for more than 20 years.

12 thoughts on “Guerrilla Warfare by Female Anoles?

  1. I’m no expert but my guess would be shes in some kind of discomfort. Maybe internal, maybe something to do with breeding and she just doesn’t wanna breed so she immediately attacks any males in the area.

    Just wondering if you have try’d to put her with other females and see her reactions?

    I hope you get it figured out. :)

    1. Thanks for the excellent suggestion, Justin. I placed the aggressive female next to another female and she immediately bit the unsuspecting female’s leg. It appears her aggressive behavior is independent of the sex of the anole.

  2. It’s great that you got this on video! In fact, I saw a similarly aggressive female in the labs at Harvard last summer — a lab tech also witnessed the event. The aggressive female would not let go of another female’s head, even when I picked the “victim” female up and removed her from the cage. When I finally succeeded in pulling the aggressive female away, she immediately began bobbing up and down and attacked the male in the cage, then other females. The lab tech and I had never seen anything like it! We actually had to sacrifice her that day (for unrelated reasons), so that was our solution to the aggression, but she did not stop attacking other lizards until the end.

    1. Natalie,

      It is fascinating to learn that you have observed this behavior also. Thanks for sharing.

      In case her behavior is linked to a bacterial infection, she was started on systemic broad-spectrum antibiotics and topical antibiotics yesterday. I’ll report back to Anole Annals if she displays any noteworthy changes in her behavior in response to these treatments.

      By any chance, did you observe any overt disease after sacrifice (if a necropsy was performed) in the aggressive female?

  3. I haven’t seen the behaviour actually happening, but I noticed something similar with a Anolis lineatus female I had in a viv for a couple of years. I got it as one of a pair, but the male soon devellopped a bad health, became shy, refused to eat an eventually died.
    So far I had no problems, but when I managed to get another male, the same happened, but the male also displayed some bite-marks, it hadn’t previously. This male was also killed in the end.

  4. Wow this is new to me. I’ve seen females get aggressive from time to time but nothing like what you’s have said. I wonder what the cause is for this? I’ll be keeping this topic in mind if you don’t mind keeping us updating.

  5. It still may have been caused by ‘discomfort’.. I have no idea how Anoles experience being confined in a vivarium…

  6. This may be the result of a brain tumor. I spoke with an anole neurobiologist a few years back about a male exhibiting unusual mating behavior. He dissected it and, lo and behold, it had a big tumor in its brain. Of course, the behavior exhibited by your female might not be so unusual. Perhaps females are more aggressive than we think. However, if she really is that vicious, it is possible that she may have a tumor, perhaps in the amygdala.

  7. I was thinking the same thing Martha, Ive seen a few pictures of A. carolinensis with tumors around the head and it scares me. Reminds me in ways of the cancer that’s ripping through the tasmanian devil population. Would hate to see that type of thing become widespread in another species.

  8. Well, the aforementioned female lived for four years after killing the last male, so at least the tumor wasn’t aggressive.
    Personally I think females of A. lineatus are more aggressive tehn we think. They tend to have quite large dewlaps for female-anoles. Which would in my opinion mean they use them somehow.

  9. Hi Allison,
    Great post. Strange behavior by the female. I’ve never seen it.

    Also, how often have you had anoles live to 7 years or older? What’s the oldest one you’ve had? I know of one person who has had a wild caught adult male cristatellus in the lab for 4 years. Figuring it was at least a year old at capture, that puts it at least 5. I wonder how long they could go.

    1. Yoel,

      On average, my A. carolinensis live 5 to 7 years. My record so far is 7.5 years and this anole was purchased as an adult so I’m guessing he was at least 8 years old when he died. My first ever hatchling, a female, lived 6.5 years. To my knowledge, the oldest reported anole lived 8.5 years and was owned by a European member of a discontinued online interest group called the “Anolis Contact Group”.

      My oldest anole at this time (the one who is about 7 years of age) is quite an anomaly in terms of health. By the age of 6 years, my anoles typically present with multiple health problems including cataracts and kidney/liver dysfunction. If any readers are interested, I’m happy to share how I treat these conditions; let’s just say it involves, among other things, regular injections of subcutaneous saline and oral herbal mixtures. Anyhow, this lizard, who was fully-grown when captured in New Orleans, LA in 2006, likely weathered Hurricane Katrina or hatched soon thereafter. I suspect he feasted upon a gourmet spread of insects in the post-flood environment and perhaps this contributes to his exceptionally good health now!

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