New Study on Color Change In Green Anoles

Green anoles can change from green to brown. Occasionally, they do it only part way. Photo from http://www.floridagardener.com/img/critters/Greenanole.jpg

Widely, if inaccurately, known as the American chameleon, Anolis carolinensis is renowned for its ability to change color from a sparkling emerald to a deep brown. Surprisingly, we don’t really know what factors determine whether a particular lizard chooses to be green or brown at a particular time.

Here’s what I had to say about it in Lizards in an Evolutionary Tree (pp. 279-281; I’ve omitted most references here):

“In theory, we might expect green anoles to match their background, turning green when in vegetation and brown when against a woody surface. Although widely believed, this idea is not strongly supported (reviewed in Jenssen et al., Herp. Monographs, 1995). In one study, male A. carolinensis mismatched the surface upon which they sat (green on brown substrate or vice versa) more often than would be expected by chance (Jenssen et al., 1995; but see Medvin [Animal Behaviour, 1990] for an opposite result). Indeed, males of green species often adopt a bright green coloration when in the survey posture, although a darker appearance would almost surely be more cryptic against a woody background; this tendency suggests the possibility that skin color is being used to make the lizards more, rather than less, conspicuous (e.g.,  Macedonia’s work on A. conspersus and Trivers’ on mating A. garmani).”

You’d think we’d have a better idea of what’s going on with color in as common and obvious a species as A. carolinensis, but even Jenssen et al.’s very detailed field behavioral studies only began to suggest some ideas. Now, a recent study of A. carolinensis on the Japanese island of Chichi-Jima has tried to take this further. By noting the color of 169 anoles encountered in the field, Yabuta and Suzuki-Watanable tried to look for correlates of color. As with previous work, they found no evidence that the anoles were matching their background (incidentally, this is true of real chameleons as well—they apparently don’t change color to blend in). Other data, however, suggested a possible role for green as a social signal. First, adult males were more often green than other animals and, second, a weak association existed between perch height and proportion of adult males that were green. By contrast, no association was found between air temperature and color, thus working against the hypothesis that dark color was used in thermoregulation.

Clearly, there is a lot yet to be learned about color change in A. carolinensis, not to mention the many other—as yet unstudied—green anoles. One wouldn’t think such work would be all that difficult, at least the field component  as an initial starting point. This study is a nice example of how one might start such a study, simply by going out and seeing under what conditions  anoles are green versus brown, and how that varies between sexes and size classes.

One last quote for LIAET, because it’s tangentially relevant:

“Color change is under hormonal control in anoles and often occurs in social encounters   (reviewed in Greenberg [2002, 2003]; the physical mechanism by which color change is produced is reviewed in Cooper and Greenberg [1992]). For example, almost half of the instances in which A. carolinensis males changed from green to brown occurred in the context of aggressive encounters (see also Trivers [1976] on A. garmani). Many of these occurred as males were approaching the boundary of their territory, but before an opponent was visible (e.g., the male which owned the adjacent territory was on the other side of a tree trunk), which suggests that the male in some sense anticipated an agonistic encounter (Jenssen et al., 1995). In general, dark color is a response to heightened stress, although a variety of other factors—including predation attempts, temperature, and light levels—also affect color in A. carolinensis (reviewed in Jenssen et al., 1995; Greenberg, 2003). During male-male interactions, lizards will change color frequently; by the end of the encounter, the winner is usually green and the loser brown (Greenberg, 2003).”

 

Jonathan Losos

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60 Comments

  1. Cool paper, thanks for posting on it!

  2. Pat Shipman

    A green Carolina anolis I saw yesterday turned very dark brown upon being caught and played with by my cat. (Yes, it survived unharmed, by the age-old strategy of not moving until the cat grew bored.)

  3. Ra

    After many years in Florida I just saw an Anole in camouflage mode for the first time:

  4. Mag

    My anole turns brown a lot. It’s probably stressed a lot because it’s been abused (ex: thrown around, dropped, shaking it, etc.) by children in the past. In taking good care of her now that those kids don’t have her. (my anole was given to me)

  5. Kyle

    I have adopted two anoles for a class project and plan to do a color changing experiment with them. I will be testing to see if different background colors will affect their color while they hunt for crickets. As of right now, the background on the walls of their aquarium are white and there is a fake green plant, a perching branch, and wood chips in the aquarium. They are usually green when they are on the walls and more of a brown while on the wood chips. I have noticed that when it is feeding time they turn brown before they eat and then back to green after they eat.

    • Jonathan Losos

      Very interesting. Good luck on your experiment, and please let us know how it comes out.

      • L

        I found out that before feeding time my green anole clover is green so that when she is hunting and after hunting her color turns brown

    • Martha Muñoz

      Hi Kyle,
      Along the lines of what Jonathan said, would you consider taking photographs and crafting a few paragraphs about what you did? I think our readers would be interested to find out. Also, I don’t know what year you are in at school, but we’re always looking for ways to include anoles in classroom projects. So please feel free to share. You can contact me at mmunoz@oeb.harvard.edu

      Best of luck,
      Martha

    • Melanie

      I caught an anole in my front yard today at first he was brown but after putting him in a container with bright green grass he is now a bright green color

  6. Arjun A bhasjaran

    Today morning I found such a creature in Dar es salaam, Tanzania, East Africa. I was eagerly searching what type of creature it is and upon a search finally reached at your article. thanks for sharing.

    • Jonathan Losos

      You found an anole in Dar Es Salaam? Do you have a photo?

  7. Sheryl Lockhart

    I was sitting and enjoying the warmth of the sun today watching an anole walking along the top of the fence. It found a nice place in the sun to rest and then changed from a bright green to a dark brown. It sat for a while then blew up its red throut a few times turned back to green and walked on down the fence. I wish I had a video of it. It was very intresting and the first time I saw one do the color change.

  8. Wow nice to know that i have a one living in my tree I found it today it stayed green and chilled I got nervouse. Because my dog cookie loves catchin lizards and I helped it to my Awacate tree it’s soo nice and preety !!

  9. I have a male on my deck of my house in coastal NC that changes color when it changes location. In the bushes (0ff my deck) it is green sometimes olive green. When it comes out onto the rail of the deck which is stained brown it changes to brown in a minute or so.

    There is a wooden retaining wall that is gray and stained with algae to a fairly dark green and this Anole changes to olive green when he is hanging out there. When he jumps back onto the deck he changes to brown. When he is moving in the direction of the retaining wall he displays the wattle thing and is changing his color to olive.

    When he is displaying on the deck he stays brown until he heads for the bush and then changes to the lighter green when he gets into the bush.

    The windows looking onto my deck area are mirrored so the lizard can’t see me observing. He is about 7 inches long and this is his first time here, that I have seen. There is a much smaller (2 1/2″) Anole that stays brown with darker spots on the backbone. I think it is female because it doesn’t display. There is also a blue tailed Skink about 7 inches that comes onto the deck to sun itself. The skink has been here for several years.

  10. hester

    i have a green anole and i beleive it changes color when it needs basking

    • I just got an anole and bought a basking light and it turned half green and half brown in a few minutes (When I originally bought him he was all green).

    • Kiersten Cawley

      Lizards actually change colors because of their mood.

  11. Jacob

    I just got my green anoles (3 still very young) and they all are a bit nervous, but curious. I have a heat pad and day light, so I have it go temp wise, and the humidity is up at 83% , but apparently, these little guys don’t like the sun lamp. I infered this when I turned it on in the morning, and the only one awake instantly started to turn brown when I turned the light on. I wonder if he’s scared of the light? The others aren’t awake yet due to the fact that it is 7:30 am, but the sun is already up. Im getting 3 others in another terrarium, and I dont want them in any stress. So, any suggestions?

    • K.Ra

      your anole probably just turned to a darker color so he could absorb more heat from the lamp to warm himself up in the early morning.

    • Maggie

      Try a lower wattage bulb it might be too hot. Some heat pads can get too hot also. I’m no expert ,but i had to do alot of research when i found a green anole on a pallet of supplies at work. Which would’nt have been that strange except for that it was December and i live in Ohio.

    • kimberly

      How can u tell how old thay are i fine one that came in side my house in the bathroom and it was green when i hold it and brown when its on the ground ? Its about 3 inch. My be or a lil smaller

  12. Sabrina A

    I just bought my first green anole today. When I first spotted her, she was a bright green on one of the fake trees in the terrarium. Now, she has taken to climbing up to the humidity gauge on her tank, and turns such a dark brown that she’s almost a black to match the color of the gauge. She was carried in a wet brown paper towel on the way home and turned that color as well. My anole’s camouflage instinct seems to be fine

  13. Shyla

    We just adopted an anole from my son’s school who had them in the classroom for a science unit. Most things that I have read indicate that turning brown is a sign they are stressed, and that being handled stresses them. She basks from fake green plants in the aquarium and is often brown, but when I take her out and hold her for a few minutes she turns green again. Does this mean she is not getting enough heat? I have a heat lamp on the tank all day and night. I’m just confused why she would frequently be brown.

    • corini22

      Your comment seems to be from a while back, but I have the exact same issue and wanted to know if you ever figured this out. Our very young anole that my son found turns green on us but is brown in the tank. It also doesn’t seem to be eating all that much. I am trying everything.

  14. tina

    Green my German sherpard chased lizardsgr around our fence.Now a green lizards Was on my kitchen couter.Looked at me n said I live here.Put him out.Guess they had babies found 2 more put them out. I WAS BAKING BROW
    NIES. PUT MY HAND ON STOVE HA NDLE N A BABY LIZARF CRAWLED OUT ON HANDL?E SAID I MOVEF N YOUR STOVE BIT YOU COOK GOOD.1ST TIME THEY MOVEF N GUEDS LIKE INSIDE DOGS BETTER THAN OUTSIDE.Is this normal lizard behavior
    ?

    • Diana

      We live in Houston, Texas and have thousands of these little creatures in our yard. I enjoy watching them and some are friendly. So sorry they are being kept inside!

  15. Erick

    I have two green anoles, I am not entirely sure if one is male and the other is female but they began to move their heads and bodies in a push up manner and one was flaring it’s neck the other went away and turned brown but I would hate for them to get into an aggressive territorial fight. What should I do?

    • Jonathan Losos

      They very possibly are both males, in which case you should separate them.

    • Valerie

      Check to see if they have a red stripe on their necks. If so, then they are males. If not, they are females.

    • The females in my yard have a contrasting design on their backs. If you have two males they should probably be separated. In the wild their territory is pretty huge. 35 Sq feet

  16. Rachel

    Honestly, my Anole loves being handled. She is brown when she is in the tank with no interaction and is green when we carry her around when we take walks or just hang out

  17. JJ

    I really think this guy was trying hard to imitate the pink stripes on the rubber lizard, which is not a behavior I’d heard of before. He’s not a pet – just a wild invader looking for warmth and/or bugs (location South Texas). Unfortunately, this was the best pic I could get in the low light.

    • Daniel

      That’s pretty interesting, i’ve heard they can simulate other colors besides green and brown slightly

  18. Devon

    I have a green anole and bahaman anole they are both males and typically you wouldn’t keep two male anoles together but they are best friends and they cuddle together at night it’s very odd I didn’t plan on keeping them together but once I discovered their docile attitude I decided they would be fine together the only time they show their dulap is when they see their reflection and my green anole seems to change Color due to temperature whenever the basking lamp is on he is Brown when I turn it off he gradually turns green he also turns green when I hold him so I think he doesn’t see me as a threat

  19. Ken

    I just observed a male Anole apparently pursuing a much smaller anole across two cast iron plants in my front yard The bigger male gradually turned brown over a three or four minutes period And then displayed his red throat once seemingly as if to attract the smaller anole or ward it away from the big Anoles territory

  20. Wren

    Seems like my backyard group of anoles turn brown as they appear to be hunting. I notice some color changing during scuffles too.

  21. Gynna

    I´m from Denmark living in Houston, I´m very fascinated by all lizards and geckoes, and just learning about them. I have, what I think is a family, of green anoles in my garden. My husband thinks I´m going crazy, because I named them and talk to them. The male, HUGO, lost some of his tail, when he fought of another anole, the tail is now growing back, and that´s why I know it is the same one visiting every day, sleeping in the same place, unless rain is falling during night. He is not shy at all, he slougs and mated right in front of me. One day, he (I think) tried to get my attention, and actually, he showed me a baby anole… The “Wife” Cirkeline is very pregnant right now, and I´m really looking forward to get to know this family better. He changes colors like this. Sitting on the bricks of the house he is bright green, tries to change into the colors of the bricks. Sitting on our wicker patio furniture he is the same brown color. I have lots of pictures of everything, and even some videos. I LOVE MY HUGO…..

  22. My son did a science project on this, and we found that aggression was, indeed, a reason for color change. We found that putting a second anole near the first caused them both to alter their colors.

  23. tricia

    My lizards tend to turn green when I feed them, the male turns green more often then the female. she tends to be green on “woody” areas as well and green.

  24. Elizabeth

    Anytime my cat catches an anole and brings it to me (which is far more often than I would like) the lizard is always a very dark color. Once I managed to catch the lizard and put it back outside it usually returns to its green color. It seems to me that when they feel threatened they are darker.

  25. Aly

    My lizards are captured by hand and I have 4 and 2 are tame. 2 are grownup and 2 are babys.1 baby tries to bite me.a baby and a group go crazy when I pick them up.the last grownup just wants to be with me.

  26. Meena

    Thanks for this post. I live in GA and have many Green Anoles in the backyard. I believe I have some brown ones as well. I’m trying to ascertain the difference.

    So sad to see some of the comments that have Anoles in captivity.
    They are not meant to be stuck in a small, confined space.

    It’s cruel.

    • Falon

      I agree I have mine in my back yard it never leaves for some reason but I love it

  27. rydalish

    i believe that like bearded dragons, when aggravated the green anole changes color.
    whenever i caught my first one, it turned dark brown.Whenever i played with it in my kitchen, it turned green once more.

  28. Falon

    I have an anole I just got it and it can turn green and brown fully it’s already shedding I wanted a green one but I love my Sam I don’t know if it a boy or girl so Sam will be a good name, thank you.

  29. Harry

    I observed two in my yard here in North Carolina and I too believe they change color in regard to mating. A large male was near a female. He was green and showing the orange throat extension. The female was sitting near by and was brown. Within a few moments she changed to green and headed toward the male. Unfortunately they then both disappeared and I could observe no more.

    • Jim

      The mating pair I have on my deck last year got it on when they were both green and also when both were near black in color. When they were black they were on some black coiled hose on a reel. I saw movement and grabbed a few pics. They perform well.

  30. Stephen

    I have a pet male green anole which I keep in a large screen terrarium. He has both basking and uv lamps, and seems to do fairly well, except he never turns green except at night. I had been concerned he was stressed, but he eats well and demonstrates no other notable signs of stress. However, he is remarkably friendly. With little effort he readily climbs onto my hand when I offer it in the cage. Once he has climbed on, he will often stretch out and relax, making no attempt to escape, and always rapidly turns a vivid green. The strange thing is, he refuses to climb on anyone elses hand, and immediately tries to escape if coaxed onto someone else.

    I have never seen any anole act like this before.

  31. stefanie cook

    I have a male and female anole. I bought them both from the same pet shop where they lived in the same tank together, just bought them a week apart. When they are in my tank they are brown all the time, when I remove one for even 30 mins they both turn green. Do you why?

  32. Chloe Baer

    My anole is very friendly and seems to turn bright green when I am holding him. When I put my hand in his habitat, he jumps on to it and doesn’t really try to get away. I have never seen a lizard so tame before. I have read that they can be nervous when you handle them, but I have never seen that behavior in my lizard. I love watching him eat crickets. He’s the coolest anole in the world

  33. Frank Pirri

    Living in South Florida we have hundreds if not thousands of them all over our yard and in the house. I can tell you they definitely change colors. We have one that turns reddish, he lives on our fire pit and even fights off other Anoles to protect his castle, it’s hilarious. And I’ve seen other ones turn completely translucent to the point of seeing there organs inside. Mostly that happens when they’re young and indoors but we saw one the other night on the white patio ceiling at night. They are amazing creatures and they are used to us.

    • Jonathan Losos

      I suspect the translucent ones you are seeing at night are house geckos.

  34. Rebecca Maxwell

    It’s “mating” season we’re assuming here in Fl because we’re seeing groups of two’s EVERYWHERE and color changes are happening all the time right before our eyes. It’s hard to tell which are the males and females because both are changing. The pic attached is lizard that went from green, to albino, to brown within minutes. He stayed at that brown because he decided to hang on the brown pipe.

  35. Linda Holt-Johnson

    Are the females brown?

  36. Brittany

    My Anole changes to a Aqua light blueish color. Is he ok?

  37. Brittany

    Come to think of it he has been red too blue is his recently new color. I think its awesome however cant find anything on why.

  38. Theresa h wunsch

    Thank you posting this gave me alot of information about these little guys 💖💜💙

  39. Richard Daniels

    As a few other commenters have noted, my observations from interacting with anoles in central and eastern NC have been that they frequently change to brown when stressed (by any number of conditions, not least of which being captured and handled). Of course that is entirely anecdotal, and without any control for factors like sex and environment.

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