Hybrid green-rock iguana hatchlings found on LC

| 20/09/2016 | 59 Comments

(CNS): The invasive green iguana has given another blow to local conservation with the discovery on Little Cayman of several hatchling iguanas which are believed to be hybrids of the invasive species and the native rock iguanas found in the Sister Islands. The unusual hatchlings have been examined by the Department of Environment’s iguana expert, Fred Burton, the manager of the terrestrial unit, but he is now waiting confirmation from genetics expert Dr Mark Welch, from Mississippi State University, that the hatchlings are the offspring of a green iguana female and male rock iguana.

Cayman News Service

Rock Iguana hatchling and hybrid (Photo by Jeanette Moss and Tanja Laaser)

The DoE explained in a release Tuesday that the strangely coloured and patterned hatchlings show intermediate characteristics for features that normally distinguish the two species and cross breeding is the only credible interpretation.

“Cross-breeding between green iguanas and rock iguanas has never been considered possible because the genetic difference between the two was thought to be too profound,” DoE experts said. “Now that it has occurred, perhaps for the first time, this must be considered a new and serious risk for rock iguanas throughout the West Indies, wherever the green iguanas have invaded.”

The first of the hybrid hatchlings was caught in the wild recently by Mike Vallee, who with fellow volunteer Ed Houlcroft coordinates the “Green Iguana B’Gonna” programme for the National Trust on Little Cayman.

Another two hybrid hatchlings were caught soon afterwards by Jeanette Moss, field assistant Tanja Laaser and Dr Mark Welch, who were in Little Cayman leading the Mississippi State University research team studying the Sister Islands’ rock iguanas, in partnership with the DoE and the San Diego Zoo Institute for Conservation Research.

Local volunteers and the Mississippi research team have been searching for more hybrid hatchlings, and although so far just three have turned up, the scientists have no idea how many more may have hatched from the hybrid nest and dispersed into the surrounding vegetation.

Cayman News Service

Green iguana hatchling (top) and one of the hybrid hatchlings (below) (Photo DoE)

The hatchlings are small, like green iguana hatchlings, with the same long striped tails but with different-shaped heads. The body shows classic rock iguana patterns of dark chevrons and spots. Under the rock iguana patterns shines a yellow base colour tinged with green.

The experts said that they do not know at this stage whether the hybrids will be fertile or even if they will develop normally. Since their presence in the Cayman Islands is a serious risk to native rock iguanas, the hatchlings will be transferred to the San Diego Zoo Institute for Conservation Research to rear and test for fertility over the next several years.

The battle to beat the green iguana is by no means a simple one but the DoE is close to confirming the next step following two experimental culls this summer. Given the massive numbers on Grand Cayman, Burton has indicated that the DoE will probably begin a programme where the reptiles are culled in several honey-trap locations – effectively drawing the invasive reptiles to safe areas where the hunters can kill them in numbers sufficient enough to at least reverse the rapidly increasing numbers.

There is now a genuine concern that the massive population of the green iguanas on Grand Cayman is so great that they pose a real and serious danger to all vegetation on the island, including endangered species and the trees and plants that feed native and endemic birds, bats and other lizards and reptiles.

“It could completely wreck the forest system and cause massive ecosystem change,” Burton recently warned.

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Category: Land Habitat, Science & Nature

Comments (59)

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  1. Anonymous says:

    The very last paragraph could apply to any Dart or NCB development. What’s the problem?

  2. Annie says:

    Are these hybrid iguanas sterile, like mules?

    • Anonymous says:

      They don’t know. They aren’t old enough yet to know if they’ll reproduce or not. (As per the article.)

  3. Anonymous says:

    Am I missing something here, are the green iguanas eating baby blue iguanas or destroying the island somehow? Is dilution of the gene pool really a good enough reason to be killing all the green ones? There is already a protection program in place for the blue iguanas so why all the slaughter?

    • Anonymous says:

      Yes, you are.

      They are eating a lot of other things. The flowers that feed our nectar-feeding birds. The fruit that feed our fruit-eating bats. And of course their ‘overeating’ the plants isn’t good for the plants themselves. They are basically very disruptive to the natural system and so need to be removed (reduced).

      If we want to preserve the native iguanas then yes ‘dilution of the gene pool’ is a problem to be avoided. You can’t preserve horses or donkeys if all you have left are mules.

  4. Anonymous says:

    We are in such a mess with these green iguanas and its going to get a whole lot worse. The last few weeks there seems to have been a explosion in the baby greens. Never seen so many little newly born looking ones.

    • Annie says:

      No lie, they are everywhere. The are like land crabs in the old days. Thank God they can’t burst my tyres.

  5. Anonymous says:

    I think we can all agree that it’s because it’s reptiles. If grand cayman was being over-run with adorable little monkeys nobody would be complaining.

    • Anonymous says:

      Oh, no, there would be complaints. Just ask Gibraltar or anywhere else if they’re happy with the ‘adorable little monkeys’ overrunning the place.

  6. Anonymous says:

    Simple solution if Honduras want the green iguanas let them take them. Problem solved, then we put a life long ban on the greens no importation of them “persona non grata”.

  7. Anonymous says:

    At the risk of being critized I hope that the conservationist people breeding the blue iguana will not be allowing too many of them to be hatched . I remember going to the the Hyatt a few years ago to take the ferry to Rum Point and observing one or two green iguanas hanging around there, now the island is over- run with them. Everybody thought it was cute, and now we have a huge problem island side. We plant and the iguanas reap by eating all the flowers before they can turn into fruit. THe government need to put in place a specific cap on the blues before they too become a nuisance. Do not allow them to reproduce at will. I also think they should be held in an enclosed area so none can leave and none can enter. I am no scientist but I do believe that animals adapt and change their habits to suit their environment.

  8. Anonymous says:

    should we really be trying to stop evolution?

  9. Anonymous says:

    Government’s approach to the green iguana issue (when they finally acknowledged the problem) was – and is still being – advised by the same scientists who declared that the invasive iguanas could not breed with the indigenous species. Scientists who have achieved great local and international recognition for their work in some areas but who seem quite oblivious to the real issue of cross-breeding and a realistic estimate of the number of greens.

    Perhaps Government should now listen to common sense, man-on-the-street views, mainly that cross-breeding is indeed possible and quite likely, and that the numbers are perhaps currently triple those estimates recently published. Thus, implement a more viable culling program ($1 per carcass) and let it continue indefinitely!! Meanwhile, Government should encourage and facilitate some commercial production of iguana meat for export and those residents who partake.

    Perhaps the wise-ass who previously accused me in this forum of “knowing more than the scientists” can lend his/her two cents!

    • anonymous says:

      So don’t expect sterile mosquitoes to be sterile after all. Nature might to able to reverse vasectomy quite easily.

  10. Anonymous says:

    Well if humans can successfully mate with Orangutans and produce Trump, this does not surprise me at all

  11. Anonymous says:

    I need to know Mr. Eden’s stance on this potential cross fertilizing dare I even say it LBGT affair. This is probably the result of a gay person visiting in 2009. See wa ya get? 🙂

  12. AP says:

    Still have blind faith in science? Still believe that genetically modified mosquitoes would not harm humans or the environment?
    Birds the size of a matchbox or monarch butterflies are able to migrate thousand miles navigating by magnetic fields. Humans can only see, hear, smell,touch and taste…
    They (the “scientists”) can release as many documents as they want to, but when science depends upon the five physical senses it is limited.
    So “Cross-breeding between green iguanas and rock iguanas has never been considered possible ” demonstrates that we know NOTHING about reality. We can only observe and describe. We can’t explain it. J
    The famous “If a tree falls in a forest and no one is around to hear it, does it make a sound?” comes to mind.

  13. AP says:

    Belief in science is an act of personal faith.

  14. Anonymous says:

    just import something that eats the green iguana’s. When the greens are all gone, import something bigger to eat whatever was eating the greens.
    Eventually we will move up to ponies or something cool to ride on.

    • AP says:

      Yep, this always works well. Kill anything in nature that poises a threat. We killed the wolves….that worked well. Killed thousands of another species of owl to protect the spotted owl (Oregon). Killed the cormorants to protect the salmon (Oregon). Kill the coyotes to protect the sheep and cows (Everywhere). Kill the bison to protect the cows (Montana). Kill the mosquitos to protect Miami from the (sham) Zika virus. Kill the deer to protect that woman’s roses (Everywhere). Cut down all the trees to stop wildfires. See the problem here? When will we ever stop villanizing nature? This sick cycle never ends.

    • Anonymous says:

      from the simpsons:
      Lisa worries the town will now become infested by lizards rather than the pigeons, but Skinner assures her they will send in “wave after wave of” Chinese needle snakes, then snake-eating gorillas, and then “when wintertime rolls around, the gorillas simply freeze to death.”

      • Anonymous says:

        Would be a good idea in some climates but would never work here. Better too just bring in the gorillas straight away.

    • Anonymous says:

      HAHAHAH, someone actually disagreed with the pony idea

      “no!, i don’t want anything cool to ride on”


      *my sides

      • Anonymous says:

        You are an idiot. Why do you think it would stop at ponies? We would end up riding dinosaurs and blimps. Is that what you want?

  15. Anonymous says:

    Baby momma culture!

  16. Anonymous says:

    There are very very few Green Iguanas on Little Cayman. There are hundreds of thousands on Grand Cayman. If Greens and Rocks could hybridize (a cross-genus hybridization) then one would expect it to occur commonly on Grand Cayman with our Rock (Blue) Iguana. It hasn’t.

    The only counter argument that occurs to me is that a Green female on Little Cayman, in the absence of any male Green Iguanas, becomes more susceptible to mating with what is available. Absence makes the heart grow fonder? But I sincerely doubt it!


    • Anonymous says:

      It was just a natural (Bracker?) reaction to a female from Honduras dressed in bright green.

    • Anonymous says:

      Your theory is plausible in the absence of green male the female green mate with the Rock. Probably won’t happen here in GCM as both species can find their own to mate with and the Blues some what tend to be true blue bloods they only associate with their own kind.

  17. Dave says:

    I wonder if the offspring can reproduce. In some cases like this, the offspring are sterile. If they are sterile, wouldn’t be ironic if importing the rock iguana to Grand Cayman caused the ultimate demise of the greens. The Lord sometimes moves in mysterious ways…….

    • Anonymous says:

      read the story…..”they do not know at this stage whether the hybrids will be fertile or even if they will develop normally”

  18. Foreigners says:

    Ah boy they breeding off our iguanas now..damn foreigners

  19. Anonymous says:

    I seem to recall, on this CNS forum, experts in the blue iguana programme previously ruling-out the cross-breeding of the invasive green with the indigenous blue, exactly because of this supposed “genetic difference”. Clearly that expert view should be re-examined now.

    Perhaps Dr. Burton might like to lend an insight?

  20. Anonymous says:

    can someone please explain how they are a serious risk to native rock iguanas? thanks!

  21. Anonymous says:

    Who do we blame for this irreversible problem?? Not now but from years ago government should’ve ordered culling. Matter of fact, pet shops should not have been allowed to sell iguanas. The children who had them as pets, got tired of having them and let them ago. Now, everywhere is infested with the pests and all the crops are being destroyed by them.

    • Anonymous says:

      This is just another example of Governments failure to act. Closing the gate after the horse is out.

  22. Until the DNA comes back it’s speculation. To state that they are hybrids, regardless of “expert” opinion, is jumping the gun at best.

  23. Anonymous says:

    So we have to accept gay marriage, but green iguanas and rock iguanas mating is an abomination? Love is love!

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