The Tropidurus Genus & Struggling with Taxonomy

Ah taxonomy…thou art a beautiful and heartless bitch. If you’ve ever looked into the tropidurus genus post 1979, you know what I’m talking about!

It’s not uncommon for friends and family to send or show me photographs of reptiles and amphibians they encounter during their holidays. They often ask me to identify the species, and usually, this can be done fairly easily - especially when you know exactly where the individual was found. However, some species can be very hard to differentiate by image and location alone.

My brother found the individual displayed in the above photograph in Rio de Janeiro a few years ago. Truthfully, I had never paid much attention to this genus before, and figuring out the species became even more complicated the more I looked into it. As Frost, et al. (2001, pp.352) very eloquently put in their publication, “from 1979 to present (…) effort on the elucidation of the systematics of the taxon has increased, seemingly exponentially”. In his 1987 paper, Rodrigues gives us a brief history of the genus and the species that were once recognised under it. Boulenger (1885) was the first attempt at revising the then established norm that the genus encompassed about 15 different species but Boulenger maintained only 3 species from the fifteen - Tropidurus hygomi, Tropidurus torquatus and Tropidurus hispidus.

In 1930, Burt & Burt classified T. hispidus as a subspecies of T. torquatus and made other changes seemingly without many valid reasons. It was only in 1963 and 1969 that some of these issues really started to be addressed and by the time that Rodrigues started his main study on the species of the Tropidurus genus, he based them on 11 recognised species that occurred south of the Amazon River. His study was made possible by the ever growing collection of the University of Sao Paulo Zoology Museum (MZUSP) that included 6,200 individuals collected from 305 different localities. His 1987 paper concluded by recognising seven Tropidurus species - T. cocorobensis, T. erythrocephalus, T. insulanus, T. itambere, T. montanus, T. mucujensis and T. oreadicus.

Since then, species of the Tropidurus genus were described and mentioned in subsequent pieces of research and I’ve had much fun (not) trying to figure out to which species the little guy from the photograph belongs.

Rodrigues’ original 1987 paper in Portuguese.

You too may have heard scientists discuss issues with language barriers when it comes to earlier scientific publications and a questionable translation of said earlier papers. While I appreciate that this occurs from time to time, I would expect this to be less of an issue nowadays. In this instance, although one of the main earlier publications on the Tropidurus genus by Rodrigues in 1987 was in Portuguese, subsequent publications were issued in English, such as Frost, et al. (2001) - in which Rodrigues is actually one of the co-authors - and Domingos, et al. (2017).

With all that in mind, when I was attempting to identify this individual, my main obstacle (apart from the obvious lack of data on the individual) was determining the current taxonomic nomenclature being used. While reading Gomes de Carvalho (2013) on the distribution and conservation of the genus, I settled on this individual possibly belonging to the Tropidurus torquatus species based on its distribution (see map below).

Distribution map presented in Gomes de Carvalho (2013)

To end the post on a positive note, a bit of a ‘fun’ fact about this genus - locals tend to call pretty much every species of the Tropidurus genus ‘calango’. Now, as you probably gathered, I am not certain I got the species right so if you have any insights, I am all ears! Drop me a line at hello@talitabateman.com and help me unravel this mystery!

References:

• Domingos, F.M.C.B., Colli, G.R., Lemmon, A., Lemmon, E.M., Beheregaray, L.B., (2017). In the shadows: Phylogenomics and coalescent species delimitation unveil cryptic diversity in a cerrado endemic lizard (Squamata: Tropidurus). Molecular Phylogenetics and Evolution, 107, p.455-465.

• Frost, D.R., Rodrigues, M.T., Grant, T., Titus, T.A., (2001). Phylogenetics of the Lizard Genus Tropidurus (Squamata: Tropiduridae: Tropidurinae): Direct Optimization, Descriptive Efficiency, and Sensitivity Analysis of Congruence Between Molecular Data and Morphology. Molecular Phylogenetics and Evolution, 21(3), p.352-371.

• Gomes de Carvalho, A.L., (2013). On the distribution and conservation of the South American lizard genus Tropidurus Wied-Neuwied, 1825 (Squamata: Tropiduridae). Zootaxa, 3640(1), p.42-56.

• Rodrigues, M.T., (1987). Sistematica, Ecologia e Zoogeografia dos Tropidurus do Grupo Torquatus ao Sul to Rio Amazonas (Sauria, Iguanidae). Arquivos de Zoologia: Museu de Zoologia da Universidade de Sao Paulo, 31(3), p.105-230.

The Yellow Cururu Toad (Rhinella icterica)

A few weeks ago, I was tidying up my portable hard drive and came across a few photographs that my brother took of a couple of Yellow Cururu Toads (Rhinella icterica) copulating.  He'd found them during a trip to the countryside of Sao Paulo, Brazil, at the end of 2011 - towards the end of the species' breeding season.

The R. icterica is an endemic species that can be found in Brazil, eastern Paraguay and the northeastern part of Argentina. It is considered to be a large toad species with males ranging from 100 - 166 mm in length and females ranging from 135 - 190 mm. Due to its sexual dimorphism, it is easy to differentiate males and females of this species - males have a distinct yellow colouration whereas females tend to be a greyish/brownish colour with symmetrical dark spots on either side of their spinal cord.

Female Rhinella icterica | Credit: Caio Biasoli

Male Rhinella icterica | Credit: Caio Biasoli

Similarly to other large toad species such as the Cane Toad (Rhinella marina), the R. Icterica has prominent parotoid glands behind their eyes.  These granular glands produce toxic secretions that look like a milky substance if you were to squeeze them. As these toads are not very agile, preferring a 'sit and wait' approach to predation, the toxin secreted is one of their only defence mechanisms. Given their size, it is not surprising to learn that they prey on pretty much anything they can swallow. Having said that, studies indicate that a large portion of their diet may be made up of beetles and ants (Sabagh, Carvalho-e-Silva and Rocha, 2012).

Interestingly, in Brazil, the term 'sapo-cururu' is applied commonly to big toads, mostly of the Rhinella genus. The word 'Cururu' is Old Tupi in origin and used colloquially in some regions to describe an ugly human male. There's also a popular children folklore song named 'sapo-cururu' that makes reference to the loud calls made by the males of the species during the breeding season. 

Female and male Rhinella icterica | Credit: Caio Biasoli

References:

• Dorcas, M. and Gibbons, W. (2011). Frogs: The Animal Answer Guide. Baltimore: The Johns Hopkins University Press.
• Halliday, T. (2016). The book of frogs: A life-size guide to six hundred species from around the world. East Sussex: Ivy Press.
• Harvey Pough, F., Andrews, R.M., Crump, M.L., Savitzky, A.H., Wells, K.D. and Brandley, M.C. (2016). Herpetology. 4th ed. Sunderland: Sinauer Associates Inc.
• Sabagh, L.T., Carvalho e Silva, A.M.P.T. and Rocha, C.F.D. (2012). Diet of the toad Rhinella icterica (Anura: Bufonidae) from Atlantic Forest Highlands of southeastern Brazil. Biota Neotrop. 12(4): http:// www.biotaneotropica.org.br/v12n4/en/abstract?short-communication+bn01612042012

The Common Egg-Eater (Dasypeltis scabra)

Taking a trip down memory lane is always a gamble. We've all had good and bad experiences but I think it's fair to say that both help shape us into who we are today. 

A while ago whilst visiting my mother-in-law, I started to truly appreciate the impressive bookshelf that my husband cultivated as a child. Reading has always been one of his favourite things to do. His bedroom's bookshelf (the one he had as a child) is filled with fantasy books. Next to these books is a picture of his child-self smiling whilst pointing at the spider climbing his naked torso. To this date, he still loves spiders and other critters, which brings me to my biggest find on the bookshelf - a book called 'Amazing Snakes' written by Alexandra Parsons which is part of the 'Amazing Worlds' series published in 1990. As I understand it, this was a birthday present he got alongside the 'Amazing Spiders' book of the same series that was nowhere to be found. 

The 'Amazing Snakes' book looked rather worn (which is a good sign if you ask me!). Judging by the wear and tear marks on the book, the most popular section was the two-page feature on the Egg-Eater. It seems that as a child, he was fascinated by their uniqueness and what he described as seemingly 'non-threatening' nature due to their lack of teeth (well, lack of teeth as we see it). 

Although the book did not specify which of the two genera of egg eating snakes it was referring to, I believe they 'lumped' Dasypeltis and Elachistodon together. For the purposes of this post, I will be focusing on the most commonly known species of the Dasypeltis genus - the Common Egg-Eater (Dasypeltis scabra).

About the Common Egg-Eater

This snake can be found in Africa, south of the Sahara Desert. It is no surprise, therefore, that most of its habitat is made up of deserts, scrubs and open woodlands. Adults can reach up to 1.1 metres in length but remain fairly thin with a diameter comparable to a human finger. They are nocturnal and usually lay anything between 6-25 eggs. 

Some snakes are known for eating Squamata eggs and have developed incredible adaptations to be able to eat these shell-less eggs. However, none have evolved quite like snakes in the Dasypeltis and  Elachistodon genera to be able to eat amniotic eggs (or 'hard-shelled eggs). The entire process is fascinating and one of my favourite topics on reptile evolution. So much so, that in his book, Life in Cold Blood, our beloved Sir David Attenborough gifts us with two pages on the egg-eater and their feeding method.

So, how do they feed? You see, despite their small girth, D. scabra can swallow eggs up to four times the diameter of their heads. The small vestiges of their teeth and jaw are covered by a soft mucosal tissue which makes both the 'teeth' and the jaw slide over the egg without breaking it (see images a and b). Once the egg is located behind the snake's throat (see image c), the snake uses its muscles to push the egg through the oesophagus.

Between its 21st and 29th vertebra, the snake's vertebrae are adorned by small down-ward spines (see image d). These spines crack the egg's shell into small pieces as the snake contracts that part of its body. The contraction is such that the snake manages to crack the egg but maintain the egg's membrane mostly intact. This allows the egg's contents to then be passed down to the snake's stomach whilst the cracked egg remains in place. The snake then regurgitates the fragmented eggshell pieces (mostly still connected by the membrane) and continue on its way.

The Pet Trade

Unfortunately, the egg-eater's seemingly non-threatening nature makes it an attractive species for the pet trade. It is often suggested as an alternative to those who may want a 'pet snake' but may not be willing to deal with live or frozen prey.

The reality, however, is that although its bite might not 'hurt', procuring its food source may not be as easy as one might think. For instance, although they can eat prey up to 4 times the diameter of their heads, the vast majority of them, even adults, will feed on eggs that are smaller than a chicken's egg. Juveniles, for instance, will often need to eat eggs that vary in size between a chicken and a quail's egg. As you can imagine, these are not always easy to find. They also tend to eat more frequently then other snake species and it is reported that their excrement can have a rather strong smell - similar to the smell reported by owners that feed their snake on chicks rather than rodents.

References & Sources:

Whilst carrying out research for this post, I came across quite a few published papers on the morphological adaptation found in the egg-eater. One of those papers, for instance, gives a good insight into the potential selective regime that may be conducive to the evolution of the species based on their morphological traits. Therefore, I have detailed below some of the most helpful sources I found and hope that you too enjoy researching this amazing creature!

• Attenborough, D. (2008). Life in Cold Blood: A Natural History of Amphibians and Reptiles. BBC Books.
• Mattison, C. (2014). Nature Guide: Snakes and Other Reptiles and Amphibians. London, Dorling Kindersley.
• Harvey Pough, F. (2016). Herpetology. Fourth Edition. Massachusets, Sinauer Associates, Inc.
• Gartner, G.E.A. & Greene, H.W. (2008). Adaptation in the African Egg-Eating Snake: A Comparative Approach to a Classic Study in the Evolutionary Functional Morphology. Journal of Zoology Vol 275, Issue 4:368–374.
• Parsons, A. (1990). Amazing Snakes. London, Dorling Kindersley.

The Red-Footed Tortoise Turning into a Pyramid (Chelonoidis carbonaria)

Out of all reptiles in existence, tortoises are one of the most widely kept as pets. This is not surprising considering that unlike other reptiles, they are perceived as mostly docile and non-threatening to humans. There's also, of course, the cuteness factor. Unfortunately, humans seem to be just as uninformed regarding their needs and husbandry as they are of any other reptilian order.

Before I start ranting about 'bad humans', let me give you a brief overview of the Chelonoidis carbonaria, commonly known as Red-footed Tortoise. If like me you too grew up in Brazil, the 'Jabuti-Piranga' as most Brazilians call them, are not exactly rare. Unfortunately, as expected of such a successfully captive kept species, wild populations are decreasing due to loss of habitat and the capture of wild individuals to meet the demands of the exotic pet trade.

Thirteen year old C. carbonaria named 'Casquinha' raised in captivity | Photograph by Caio Biasoli

Their habitat varies from rain forests to savanna areas and they can be found through most of northern South America (though going as far south as Rio de Janeiro in eastern Brazil), Central America and the Caribbean - where they have been introduced to many of the islands.  Although there's a lack of data to confirm an average lifespan, both males and females reach sexual maturity at around 5 years old. They are diurnal and rather sedentary compared to other species.

Although their diet consists mainly of fruits and flowers, they are also known to consume dead and living foliage as well as carrion. As there's a lack of data on their lifespan, it is difficult to specify the size this species can reach. However, sexual dimorphism has been observed, with males being larger than females. If you'd like to know more about morphological variations and sexual dimorphism in C. carbonaria, I have included a great paper published in the Brazilian Journal of Biology in my references below - the paper was published in English and Brazilian Portuguese. It is worth noting that the C. carbonaria is more widely spread in the wild than its counterpart C. denticulada. The paper I mentioned above covers both species. 

Casquinha, a C. carbonaria raised in captivity estimated to weigh 4-5 kg at age 13 | Photograph by Alex Bateman

In Brazil, for instance, the C. carboaria is protected by IBAMA (the Brazilian Institute of Environment and Renewable Natural Resources). The sale and breeding of the species is restricted and you could receive a hefty fine for keeping it without the correct documentation. Despite the protection, they are still widely kept as pets illegally. As expected, they end up receiving a pretty pore excuse for 'care' in the hands of most humans. 

As is unfortunately the case with most pet reptiles, many captive kept C. carbonaria suffer from calcium deficiencies and metabolic bone disease (MBD) as well as parasites (internal and external) and respiratory infections. The C. carbonaria can also suffer from shell rot and something called 'carapace pyramiding'. If you look at the three images above - especially the one used as the header for this post - you will notice that the carapace of the C. carbonaria I am holding is forming little pyramids.

Healthy wild C. carbonaria with no signs of carapace pyramiding | Photograph taken by Dr Steve Barten

 This is something that occurs in many captive-kept tortoises and is not reversible. Although most cases, unless extreme, don't pose much of problem for the tortoise, it does give an indication of the conditions in which the tortoise is being kept as well as its diet. In fact, the effects of overfeeding and a high protein intake have been extensively discussed when it comes to the occurrence of pyramiding in tortoises. I would also like to highlight that, in addition to the wrong diet, dry conditions are also a contributing factor to pyramiding . If you look at the image of the wild C. carbonaria to the right, you will notice that this adult shows no signs of pyramiding. 

The reason I am focusing so much on the 'Pyramiding' issue is that it can be clearly observed in the C. carbonaria individual shown in the first three photographs. The photographs, in fact, clearly illustrate the problems with the husbandry 'techniques' being applied to this little red-footed tortoise. You see, compared to other captive tortoises in Brazil, this individual has a pretty good life. It has space, seems to be pretty comfortable with its 'territory' and is bathed often to address the lack of humidity issue. However, it also has lots of company. From other tortoises, you might ask? Well, no. It has lots of company from cats and its entire diet is essentially made up of cat food.

This is a problem for two main reasons. Firstly, housing tortoises domestically with cats, or any other animals really, may lead to intestinal blockage due to fur ingestion overtime (thank you Karen for the tip). Secondly, as I mentioned before, these tortoises' diet in the wild is mostly made up of fruits and flowers. If you just have a look at the back of the package of any standard cat food, the level of protein they contain is pretty high. Now, imagine this 13-year-old individual, being fed cat food and housed with cats for almost its entire life. Sad, I know.

Nonetheless, unaware of just how bad her current situatio is, and its impact on her health in the future, this individual seems pretty happy. 

References & Sources:

• Barros, MS., Resende, LC., Silva, AG. & Ferreira Junior, PD. (2012). Morphological variations and sexual dimorphism in Chelonoidis carbonaria and Chelonoidis denticulada. Brazilian Journal of Biology 72:153-161.

The Goliath Frog (Conraua goliath)

The Conraua goliath is one of those species that most people with no interest in amphibians will have heard of because of its size. The 'biggest frog' factoid being an almost must for any pub quiz...or perhaps more realistically, for any pub quiz I would certainly enjoy.

I decided to write about it due to a dream. Yes, that's right, a dream. Not long ago I dreamt that I found a large C. goliath specimen in my garden and I was over the moon about it. I mean, a living and breathing Goliath Frog in my garden! In England! The downside of this dream was that in it, I was the only person able to see the frog. The dream version of my husband couldn't see it at all...oh, the frustration! The next day, I was telling my friend Steven Allain about my strange dream. Realistically, he's one of the only people in my day-to-day life who would truly appreciate the frustration that my dream-self was experiencing. We got talking about C. goliath and I then decided that I would write a post about it. Why not? If I believed in such things, I would say the dream was a sign and all that. So, here it is.

C. goliath tadpole | Photograph by Steve Atkin

Most people will know that the C. goliath - commonly known as the Goliath Frog or Giant Slippery Frog - is the largest species of living frog on the planet. Records show that adults average at around 12 inches in length and 3 kg in weight. Curiously, although the adults of the species are carnivores, the tadpoles are herbivores. In fact, the C. goliath tadpole's early diet is rather restricted and made up mainly of the Diacraeia warmingii plant. Unfortunately, as the range of this plant is limited, the spread of the C. goliath in the wild is also restricted to parts of Equatorial Guinea and Cameroon. As adults, however, the C. goliath's size means that almost anything is a potential meal. A  few sources indicate that a researcher has found evidence of bats in the contents of a captured C. goliath individual's stomach. However limited the evidence may be, it does suggest that these frogs are able to catch bats to begin with...considering that this species can leap up to 10 feet, catching bats becomes a somewhat more believable feat.

Vendor showing his available C. goliath collection for sale in Cameroon | Photograph taken from The African Gourmet's website

Unlike most frog species, the males are usually bigger than the females. This may help explain another unusual characteristic of the species - males do not possess nuptial pads. Nuptial pads in male frogs are used to facilitate the grasping of the female during mating. Another curiosity in their biology is that although they have an acute sense of hearing, they do not possess vocal cords. Therefore, they do not produce sounds during the mating season as many other species of frogs do. C. goliath males will instead create round pools of shallow water by riverbanks and wrestle each other for the right to mate.

Their short mating season ranges from July to August and females will lay hundreds of eggs. Unlike other frog species, these eggs will receive no protection from the parents and the surviving tadpoles will take between 85-95 days to metamorphose into frogs. They rarely breed in the wild and captive-breeding is unfortunately also rarely successful. Furthermore, the Goliath Frog's meat is part of the diet of many African tribes and considered a delicacy by local people. Combined with the hunt for wild individuals in order to meet the demand of the pet trade, you will not be surprised to hear that this species is listed as endangered. 

Goliath Coffee's logo

To address this issue, Dr. Gonwouo Nono LeGrand and his team at the Cameroon Herpetology-Conservation Biology Foundation (CAMHERP-CBF) are working to tackle the threat of over-harvesting as well as habitat loss. The Global Wildlife Conservation (GWC) also supports the work being carried out by the CAMHERP-CBF and helps spread the word about their efforts. It is lovely to see businesses getting involved. A great example is a Vancouver based company,  Goliath Coffee, that sources all of its coffee from Cameroon showing its support for the cause. They even have an entire section of their website dedicated to it - check it out.  

If like me, you too like reading about this amazing frog, I have listed my main sources below. If you know of any other major projects aimed at the conservation of the Conraua goliath, do let me know! I'd love to hear from you. 

References & Sources:

• Mikula, P. (2015). Fish and Amphibians as Bat Predators. European Journal of Ecology 1:66-75.
• Soulsby, D. (2013). Animal Cannibalism: The Dark Side of Evolution. Sheffield, 5m Publishing.
• Mattison, C. (2014). Nature Guide: Snakes and Other Reptiles and Amphibians. London, Dorling Kindersley.
• Halliday, T. (2016). The Book of Frogs: A Life-Size Guide to Six Hundred Species From Around the World. Lewes, Ivy Press. 
• Attenborough, D. (2008). Life in Cold Blood: A Natural History of Amphibians and Reptiles. BBC Books.
• Dorcas, M. & Gobbons, W. (2011). Frogs: The Animal Answer Guide. Baltimore, The Johns Hopkins University Press.
• Beltz, E. (2005). Frogs: Inside Their Remarkable World. New York, Firefly Books.

The Very Endearing Common Toad (Bufu bufo)

If you are lucky enough to have ever witnessed a wild common toad hunting, you will understand what I mean when I say that they are pretty endearing creatures. They have an incredibly entertaining 'walking' style that never fails to make me laugh.

Towards the end of my trip to Slovenia, I encountered the most gorgeous common toad specimen. As I was not actively searching for this species, it was a really nice surprise - mostly because the encounter reminded me just how much I enjoy observing them. 

The toad showed up in the garden of the place where we were staying. It had rained quite a lot during the day and by 8:30 that evening, the garden looked like a slug & snail fest. The toad was too busy hunting snails and slugs to realise that I had already spotted it and was close enough to pick it up without much effort... not that common toads are difficult to capture under normal circumstances but it makes for a nice tale.

Not long after I picked it up, the toad (understandably frightened) released water from its water bladder. This prompted my surprised (and slightly disgusted) husband to jump three feet away from me and say 'Oh no, it's peed on you'. This defense mechanism is fairly common and although it isn't exactly the same as actual urine, the 'peeing on you' seems like the easiest way to explain it.  

Common Toad (Bufo bufo) found in Krizevci Slovenia

Underside colouration and markings of the same Common Toad (Bufo bufo) individual

You will notice in these two photographs (sorry for the bad quality!) that I am wearing gloves to handle the toad. Let me firstly clear things up - you CANNOT get warts from handling toads (yes, some people really do ask that question). The real reason I am wearing gloves is to protect the toad from any harmful chemicals I most likely had on my hands and NOT to protect myself. As I mentioned before, the encounter was a surprise and although you cannot see it in the photographs, I was pretty sunburnt. I knew that my hands were covered in body lotion and, as amphibians have permeable skin, in order to protect the little toad, I put on the first pair of gloves that I could find. Obviously, they weren't the best fit but they did the trick.

A curious fact about the common toad is that they can actually secret large amounts of a distasteful white substance from their skin when threatened - although this doesn't seem to affect some predators such as Grass Snakes. Their eggs and tadpoles are also thought to be distasteful - a fact that is believed to contribute to its successful survival rate when compared to other amphibian species. It is also likely to somewhat explain the wide range of locations in which the species can be found. 

Common Toad (Bufo bufo) found in Krizevci, Slovenia | Photograph by Talita Bateman

Unfortunately, this species tends to be attacked by Flesh Flies (Lucilia bufonivora) - its latin name is certainly a clue! The fly lays its eggs on the toad's skin and once the eggs hatch, the little maggots will often enter the toad's body via its nose and eat the toad from within. Quite the image huh?!

On a lighter note, the good news is that this species is not very difficult to find. If you are in the UK, depending on where you live, you can even encounter it in your own garden! If you go looking for them, try and remember a couple of important things: 1) Common Toads are nocturnal! 2) Record your sightings!

The Mediterranean House Gecko (Hemidactylus turcicus)

Like many other small gecko species, the Hemidactylus turcicus is one of those species that we tend to take for granted. The type that most people will see on the walls of the house they rented for their holidays but never really stop to think about.

Growing up in Brazil, I would often see other species of the same genus such as the H. mabouia and the H. frenatus around the house. Unfortunately, I am ashamed to say that when I was around 6 years old, I did capture one and tried to keep it as my pet whilst "feeding" it vegetables. However, as I grew, I became more interested in their behaviour and started to study their biology more closely.

Most Brazilians will look at these small geckos and call them by the exact same common name - lagartixa. It doesn't matter what type of gecko it is. If it is on the wall and small, it's a lagartixa. This sort of 'non-reaction' is what drove me to write about the H. turcicus in the first place. When people think about reptiles they will often imagine big snakes and lizards. They will say things like 'I don't like reptiles' but wouldn't bat an eyelash at the little geckos on the wall. These tiny little creatures are reptiles too - and they are fascinating!

Figure 1. H. turcicus toe

I encountered my first H. turcicus during a trip to Ikaria, one of the Greek islands. In my head, I immediately started comparing their colouration, size and behaviour to the tropical species with which I am familiar. The similarities, as expected, are many - they are insectivores, active during the evening or night and can be found near human dwellings on dry stone walls. They tend to hide under rocks during the day or inside cracks on the walls. Like many other geckos, they tend to sit near light sources that attract moths and other insects. You can sometimes find a small group of the H. turcicus banded together near light bulbs appraising potential prey. Hayley & Blackshaw (2015) had a research article published in The Herpetological Bulletin on how habitat structure may affect the foraging behaviour of the H. turcicus that is definitely worth a read. 

Although they have adhesive toes that help them cling to walls and rocks whilst maintaining even an upside down position, the adhesive pads don't extend to the end of the toes. Instead, they stop short of the tip of the toe where a small claw helps the geckos grip to rougher surfaces. This is illustrated in Figure 1 (Arnold & Ovenden, 2002, plate 20) where the diagram clearly shows where the adhesive pads end and a little claw sticks out from the tip of the gecko's toe. The photograph in Figure 2 gives us a better idea of what this looks like in real life.

Photograph by Gary Nafis

It is no secret that instances of cannibalism occur in many reptile and amphibian species worldwide. Geckos are no exception to the rule. For instance, David Soulsby noted evidence of cannibalism in one of H. turcicus' most similar species - the Common House Gecko (H. frenatus) in his book 'Animal Cannibalism: The Dark Side of Evolution'. Although he did not mention H. turcicus specifically in his book, it is not a stretch to imagine that such a successive invasive species would display instances of cannibalism. Other gecko species have been reported to prey on smaller gecko species as well as smaller individuals of their own species. Parves & Alam (2015) highlight this occurrence in their paper published in The Herpetological Bulletin with H. flaviviridis as an example. As they noted, however, an individual's size would greatly affect its ability to predate on other individuals.

As some types of geckos are commonly kept as pets nowadays, it may come as no surprise that some species can produce a high pitched sound similar to a squeak when they feel threatened. Males of the H. turcicus species are known to be fairly territorial and warn-off competitors through a series of clicks and squeaks. It's important to note that these squeaky sounds are also used in a range of other social situations such as calling and attracting potential mates.

Females tend to lay a couple of eggs 2-3 times a year. They usually hide their clutches under rocks or in cracks where the eggs stay for 6-12 weeks before hatching. Younglings tend to be translucent pink in colour with a banded tail.

Next time you spot a gecko on the wall, try to get a good look at it - maybe take a couple of photos if you can. This will help you identify the gecko species and will make these encounters all the more interesting!

References:

• Arnold, N. & Ovenden, D. (2002). A Field Guide to the Reptiles and Amphibians of Britain and Europe. London, Harper Collins Publisher.
• Soulsby, D. (2013). Animal Cannibalism: The Dark Side of Evolution. Sheffield, 5m Publishing.
• Mattison, C. (2014). Nature Guide: Snakes and Other Reptiles and Amphibians. London, Dorling Kindersley.
• Haley, T. & Blackshaw, R. (2015). Does Habitat Structure Affect Foraging Success in the Mediterranean House Gecko, Hemidactylus turcicus?. The Herpetological Bulletin 133: 10-12.
• Parves, N. & Alam, S.M.I. (2015). Hemidactylus flaviviridis: Predation on Congeneric Hemidactylus frenatus in Dhaka, Bangladesh. The Herpetological Bulletin 132: 28-29. 

Parasitology: Snake Mites (Ophionyssus natricis)

Parasitic infections are not only one of the most common types of diseases in reptiles and amphibians but it is also one of the main causes of death in reptiles. In this post, we will focus on any reptile keeper's nightmare - mites!

The most common type of mite to infect reptiles is the Ophionyssus natricis, commonly known as Snake Mite. However, please note that reptiles and amphibians can be infected by other types of mites as well. 

Mites are ectoparasites. This means that they live on the surface of their host's body and so are usually visible to the naked eye. They mostly affect lizards and snakes with tortoises showing lower numbers of this type of parasitic infection. They are an absolute nightmare to control if you have a numerous collection of reptiles as they can be transmitted from one reptile to the other and can carry diseases as well as cause disease themselves. Interestingly, snake mites can be transmitted to humans and cause septicaemia by transmitting bacteria - this is known as Zoonoses.

Reptiles with a heavy mite infestation will usually suffer from anaemia due to blood loss. Mites tend to target protected areas of the outer body such as under the scales, eyes, ears, mouth and under the tail. It is thought that a cluster of mites at the corner of a reptile's mouth can contribute to mouth rot.

Although mites can be visible to the naked eye, they are extremely small creatures and can be very difficult to spot at times. They also tend to hide in areas that are less visible unless one is closely inspecting a reptile's body. Therefore, reptile keepers must watch out for signs that their reptile might be infected. For instance, some reptiles will spend longer periods soaking in their water bowls whereas others may show a lack of appetite, regurgitate their meal or have difficulty shedding their skin. Of course, some of these signs can indicate other types of illnesses altogether. However, when linked to a mite infestation, they usually indicate a heavy or prolonged exposure to it. 

Most vivariums will present optimum conditions to the proliferation of mites. They develop from egg to adult stage within 6 days with adults living from 10 to 32 days. They can easily escape through ventilation vents and infect any other vivariums in the room. If a mite infestation is identified, the incredibly difficult battle against them begins!

The very first step a keeper should take is to consult a specialised vet. They will not only be able to present you with the best treatment for your reptile but also help you with the best method of controlling the infestation in the vivarium and its accessories. While you wait for your vet appointment, try soaking your reptile as often as possible to help alleviate the symptoms caused by the annoying little buggers.

If you keep reptiles and would like to know more about mites, I would highly recommend Paul Schneller and Nikola Pantchev's book 'Parasitology in Snakes, Lizards and Chelonians: A Husbandry Guide'. It explains many different types of parasitic infections that reptile keepers may come across and so it is a great point of reference. However, I would like to emphasise that the book DOES NOT substitute a visit to the vet. Although it mentions the most usual methods of treating certain parasitic infections, only a qualified reptile specialist vet will be able to accurately diagnose your reptile. The book is merely a point of reference if you want to know more about the subject and be better prepared to avoid them as well as spot any symptoms that your reptile may be showing.

Snakes And Their Bad Reputation

When people find out that one of my pets is a snake, their first reaction tends to be a fearful 'yuck' followed by 'Does it bite? Is it poisonous?'. There are a few things wrong with these questions but let's first address the fearful 'yuck' reaction.

Most people's initial reaction to reptiles is usually not good. However, unlike any other type of reptile, snakes seem to instill an immediate strong fear reaction. There are a number of reason as to why that is the case. Some studies suggest that the fear of certain creatures are rooted in evolution. However, as we grow, this fear tends to be exacerbated by unrealistic society trends as well as lack of knowledge. Therefore, I am a strong believer that education is the best way to tackle this issue and prevent the unnecessary killing of snakes based on fear and misconceptions. 

This brings me to my second point. Let's now tackle the 'Does it bite?' question. In short, yes, it can bite. However, so can dogs, and in fact, so can you. A good question to ask yourself would be, why would it bite? It could be a number of reasons. A snake might be trying to protect its territory. Or it may feel threatened and scared. By analysing a situation and the environment in which the snake is found you could have a better idea of the reason why it would try and strike. It is worth noting that snakes are ectothermic and so cannot regulate their own temperature. Therefore, they rely on external heat sources to warm themselves up and ensure that their metabolism works as it should. This means that they tend not to waste any energy unless they feel it is absolutely necessary.

As to the question 'Is it poisonous?', we will first need to correct the use of the word 'poisonous'. Although in day-to-day life they seem to be used interchangeably, the terms 'poisonous' and 'venomous' actually mean different things. It is true that once in the body the chemicals do similar damage. However, venomous creatures need to introduce the venom by either biting or stinging. Therefore, a more accurate question would be 'Is it venomous?'. 

Poisonous creatures have a more passive approach. In this instance, the harmful substance could line the surface of their skin or be stored within the creature's body. Therefore, the chemicals would need to be passed through touch, such as with the poison dart frog, or acquired by diet. In a way, one could argue that poisonous creatures evolved mainly from a defense mechanism perspective whereas venomous creatures evolved mainly for offense - though as it is often the case in nature, there are almost always exceptions. 

Now, moving on to answering the 'Is it venomous?' question. Most snakes in captivity will not be venomous. To handle venomous species one would be required to have special permits and licences. However, as we all know, wildlife trafficking is nothing new so, I am sure that some unfortunate venomous snakes are in fact being held in captivity by heartless humans across the globe. It is worth noting, however, that the only venomous species in the UK is the adder. Adders are particularly shy and often avoid humans, movement and other creatures altogether. There are more cases of dogs being bitten on the nose because they were sniffing around and adder's hiding place than humans. When humans are bitten, it is usually a pretty unlucky accidental encounter and fatal casualties are EXTREMELY rare. 

It is easy for humans to let fear cloud their judgement and not see the important role that snakes play in the ecosystem and to scientific research. If you are afraid of snakes, I hope this post helps you to understand these mysterious creatures better and encourages you to learn even more about them.

Illustration by Liz Climo

The Common Lizard (Zootoca Vivapara)

The Common Lizard (Zootoca (formerly Lacerta) Vivapara) is one of the most adaptable and widespread reptiles in Central and Northern Europe. In fact, unlike any other species, it can be found as far north as the Arctic Circle in Norway. With reptiles being almost exclusively ectothermic, seeing a lizard thrive in mostly cold climates is truly amazing. 

Adult Common Lizards are usually between 85-170mm with the thick tail accounting for approximately 2/3 of the lizard's length. Males are usually darker than females, sporting a more defined patern of pale spots along the centre of their backs. However, in places such as Dorset in the UK, this already varied colour pattern is taken to a whole new level with some Common Lizards sporting a rather vibrant bright green. In these cases, they can easily (and are often) mistaken by Sand Lizards (Lacerta Agilis) in habitats where the two species occur. However, it is thought that this colouration is mostly due to lighting rather than actual pigmentation.

In his book 'Cold Blood: Adventures With Reptiles & Amphibians', Richard Kerridge discusses in extent the extremely varied colouration of these lizards. He also discusses how versatile they are when it comes to habitat. Although they are easily spotted in a variety of different habitats they seem to prefer some dampness and will often shy away from greater heats, retreating to shaded areas. They can even be found in meadows where not many pheasants are present. 

Common Lizards can be found in most of England and Wales and are widespread in Scotland with the exception of the Outer Hebrides and a few Western Isles. They are also the only reptile species found in Ireland at all. They are one of the first reptiles to appear in spring - sometimes as early as February if temperatures are mild - and usually don't go into hibernation until November. 

Another testament to their adaptability is their ability to tolerate others of the same species. They rarely fight for territory and will often be spotted sunbathing in groups. When sunbathing, like many lizards, they will flatten their bodies and spread their legs - even turning the soles upside down to absorb as much heat as possible. 

They are extremely agile and are fast hunters. These lizards have excellent hearing and will often track their prey by sound alone. Although they get most of their water from the insects they eat, they will sometimes lap up droplets of water from rain or dew from leaves and stones. Speaking of their agility, although they are mostly terrestrial, they can be pretty good climbers, often found on garden fences and trees in search of that elusive sunny spot. 

Their courtship and mating usually starts in April and May with live young being born 3 months later. It is worth noting, however, that in some places in Spain and France, these Lizards will actually lay eggs that will hatch shortly after. The young are usually between 5-12mm in size and almost entirely black. They are also almost immediately fully independent from the parents, often fending for themselves less than a day after birth. 

Like many lizards, the Common Lizard is able to voluntarily shed its tail in order to escape predators. The new tail will start regenerating from where the vertebrae was severed but (as it is the case with most lizards) the new tail is never as 'nice' looking as the original. They also shed their skin in the same way that most lizards do. Unlike snakes, they shed a different part of their body at a time. This process occurs within a period of a few hours to a few days. Whilst they are growing, they can shed from 8-10 times during the summer months. 

Unfortunately, a lack of studies on wild species means we do not have an accurate measure of their lifespan. However, a study conducted in 1971 with 6 captive bred young being raised in outdoor vivariums concluded that the majority lived up to 8 years with one living up to 10 years.

If you'd like to know more about the Common Lizard, I would highly recommend David C. Wareham's book published by the British Herpetological Society 'The Reptiles and Amphibians of Dorset'. You can also find a lot of information on similar species and compare their characteristics.