Tag Archives: Cyclura

Little Cayman…Little treasure….Not so little iguanas!!

Here I am. Once again chasing lizards, and once again in one of the most beautiful corner of paradise on this earth: Little Cayman. This tiny and gorgeous island is located south of Cuba, in the Caribbean sea.

This time, though, the lizards I am looking for can be rather large and scary. In fact, if I didn’t know any better, I would have thought that dinosaurs were still walking the earth ūüôā

The species we are looking for is Cyclura nubila caymanensis, aka SIRI (Sister Islands Rock Iguana). The common name derives from the fact that this particular subspecies of rock iguana is only found on Cayman sister islands: Little Cayman and Cayman Brac.

I am helping a former colleague of mine, Jen Moss. As part of her PhD project she is monitoring the nesting activity of SIRIs on Little Cayman (she also has some collaborators helping on Cayman Brac, but the primary site is here on Little Cayman).

The job consists in periodically checking the locations where female iguanas started to dig a nest. When the nest has been completed, eggs laid, and when the female has stopped to guard the nest we start the digging. The idea is to reach the egg chamber, collect the eggs, take measurements (count, weight, size), and then place the eggs back where they were and cover the nest. During hatching season Jen will use these data to estimate hatching success and other metrics that will be useful for her project.

This is what a nest looks like from the inside. It usually consists of a tunnel, up to 3 meters in length and ~1 meter deep, that culminates with an egg chamber. The chamber can contain up to 20 eggs. The age/size of the female usually is a good predictor of how many eggs she will be laying.
I got eggs!!!

In many cases we also know  which female dug a specific nest. With the help of molecular genetics Jen will be able to use such information to infer multiple paternity or the possibility of communal nesting.

Me “hugging” a very large male of Cyclura nubila caymanensis.
Another large male dubbed “Tank”, for the size of his jawls.
The typical and super pretty orange flowers of Cordia sebestena var. caymanensis.
Agave caymanensis. These yellow flowers are found on very tall “spikes” (up to 6 meters) originating from the “classic” Agave rosette of succulent leaves.
Butterflies are not really my forte, but this is probably a male of the Florida White Appias drusilla.
Coereba flaveola sharpei, aka the Bananaquit.
Here is a cicada. One again, I am not an expert when it comes to insects. Cayman Islands have 3 different species of cicadas, one per island. I took this picture on Little Cayman and I am assuming this is Diceroprocta caymanensis. These guys are loud when they start to sing.
Chordeiles gundlachii, the Antillean Nighthawk
Elaenia martinica. Not sure what the common name for this bird is, but some people call it Top-Knot Judas or simply Caribbean Elaenia.
It wouldn’t be a real post on a Caribbean Island without a curly tail lizard. Leiocephalus carinatus granti.

And now I give you one of the coolest iguanas I have ever seen while doing field work. We ¬†named him Machete, for the obvious injury that seems had been done with a machete (we don’t really know how it happened, but this guy has been fine and kicking for three years now).

I guess I feel affection for this iguana because it reminds me of a couple of things. First, that even if sometimes life sucks, you got to find a way to carry on, just like this iguana is doing (as my girlfriend would say “You gotta suck it!!!!”).

Second, this individual is a constant reminder that if left alone in their respective habitats Cyclura iguanas, and other iguanas as well, are incredibly tough animals. They can endure even bad injuries like the one showed in the picture below.

And yet, without the help of researchers like Jen, myself and many others, they probably wouldn’t be around. Humans, and the species that usually tag along with us like cats, rats, dogs and farming animals, are the number one threat for these big lizards. Fortunately, the good work that Jen is doing on Little Cayman, and that other researchers are doing on other islands in the Greater and Lesser Antilles gives me hope for the future of these incredible animals.

Machete!!

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The boa strikes back!

Our mission here on Big Ambergris Cay was to work on iguanas. And we did, don’t get me wrong. We collected some really good data, including some relative population abundance data through the use of road transects. Moreover, a party of two researchers from the RSPB (Royal Society for the Protection of Birds) were helping us during this trip. They were particularly interested in collecting data on the possible presence of invasive mammals like rats and mice. Luckily it seems that these rodents are not present on the island, which is, of course, good news for iguanas and the rest of the¬†endemic fauna. Giving the¬†additional development planned for the island, the RSPB crew will also help in the development of a biosecurity plan for Big Ambergris Cay.¬†With incoming barges full of materials hitch-hiking of undesired animals is possible and a biosecurity plan is fundamental to keep rats off the island.

Sarah Havery, from the RSPB crew, handling a male iguana at Calicos Jack.
A female iguana hanging on a tree. When shrubs and small trees have new foliage iguanas like to climb on branches to reach out for the new leaves.
A close up of the same iguana.

The title of this post, though, gives away the fact that the great protagonists of this trip were also boas. During the week on Big Ambergris Cay we had more than one encounter with these reptiles. A couple of nights ago some of the permanent workers of the island found a rather large female boa hanging around the dorms.

Me (holding the boa’s head and body), Dr. Gerber (center) and George Waters (with the hat), processing the boa.

In previous posts I showed a few pictures of a boa having lunch with a curly tail lizard. Boas are predators, and juvenile iguanas, 1 or 2 years old, are approximately of the same size of an adult curly tail, if not smaller.

Yesterday, during our last road transect we saw and documented a boa eating a juvenile iguana. We know this happens on the island, but documented records are rather scant.

We were cruising on the island looking for iguana to log during our transect and my eyes picked the cutout of a boa on the ground. It was about 16:50 in the afternoon. Boas are generally nocturnal predators and the first thing that I thought was a road kill. We stopped to check whether the animal was one previously captured and marked. We were all surprised to find out that the boa was well alive. The one not doing so well was the juvenile hanging from its mouth.

What probably happened is that the boa found the iguana’s burrow and went right in. It likely¬†strangled its prey in the burrow and then pulled it out to eat it outside. When we arrived the boa was taking the little iguana towards some bushes, probably to eat it away from the sun and in a more sheltered area.¬†Here are a few shots that I took with my camera. Enjoy, comment, share.

How and what does a snake in the TCI eat again?

Imagine you want to eat something. Those who are lucky and have easy access to a food source would probably go in the kitchen, open the fridge, get some food and start eating with knife and fork. What happens if you don’t have hands, or limbs? And what if you don’t have access to an easy food source and you have to go out there and hunt down your prey?

Well, things can get a little more complicated in that case.

On Big Ambergris Cay, Turks and Caicos Islands, the rainbow boa (Chilabothrus chrysogaster) has to deal with all of these problems. And yet, it doesn’t seem to be doing too bad. The sequence of images below shows a boa, about 60 cm long, swallowing its prey. In this case the victim is a curly tail¬†lizard (Leiocephalus psammodromus), ¬†but larger boas can eat young and subadult iguanas too. After this pantagruelic meal the little boa will probably crawl in its retreat and digest for the following two weeks.

 

A male adult iguana was right there when this gruesome show was going on.

Iguana Work on Little Cayman

I couldn’t have thought¬†of a better way to end this hot summer than some iguana field work. I am on¬†Little Cayman now,¬†helping out my colleague and friend Jen Moss with the data collection for her PhD project.¬†She works with the Sister Island Rock Iguanas, Cyclura¬†nubila caymanensis.¬†As part of¬†her project she is¬†trying to monitor the reproductive activity of adult iguanas on this beautiful island.

In the last couple of months Jen spent quite some time in the field tracking down females and trying to figure out where they nested. Now is hatching time and, with the help of four volunteers, including me, she is trying to monitor how many hatchling will come out from the nests that she was able to identify. Briefly, this is how it works:

  • identified nests are surrounded by an enclosure (we generally use metal flashing)
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Hatchling enclosure
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Hatchling enclosure

 

 

 

 

 

  • the enclosure has to be large enough to make sure that the egg chamber (which is underground) is inside it
  • we build a little shaded area in the center of the enclosure, to make sure the hatchlings can get away from the sun
  • each enclosure is monitored every 2 hours so that the hatchlings do not spend too much time inside the metal flashing
  • after processing them, the hatchlings are finally released in the wild

The work is rather exhausting. Patience is probably the main ingredient for such kind of work. Walking all day long across the island checking on those enclosures is no joke. The heat, the mosquitoes, the sweat, the sun, and the occasional iguana that hasn’t been tagged yet….all these factors can make the days veeeery long and tiring. Luckily, Jen is not alone in this endeavor. She has three volunteer helping her. Me? Well, I am the fourth one, tagging along to learn more about the nest work and how to deal with hatchlings.

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David Herz and Tanja Laaser applying colored beads to an adult for quick remote identification of individuals.
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Jen Moss (aka DaBoss) holding a rather large male. Anna Jackson is about to collect head measurements of this individual.

Stay tuned to learn more about these wonderful animals and see pictures of the adorable babies.