Last updated: 29 December 2010. Added section on Community Cages.

My experiences with and observations of

Plated Lizards

Gerrhosaurus major

History | Sexing | Feeding | Tameness | Things to watch out for | Bathing | Health | Breeding and the Relationship of a Pair | Community Cages | Conclusion | Summary of Gerrhosaurus Requirements | Bibliography

History

While my wife and I were looking at acquiring our first lizards in PetWorld in 1996 (see Leopard Geckos), I noticed a pair of much larger brown lizards in a tank nearby. Unlike the tubercular thin skin of the geckos, the skins of these creatures were covered in square plates and they were long, solid-bodied but at the same time streamlined animals. Most fascinating of all, they had rather obvious ear openings in the sides of their heads that light seemed to shine through from the other side. I was fascinated by these plated lizards.

At the time I considered it was a big enough commitment taking on two smallish geckos, so I thought no further about these. But we used to go down to the shop regularly for food for our new pets, and I used to go and have a look at what reptiles were being sold that week. Geckos, skinks and iguanas seemed to come and go, plus a few snakes, but the plated lizards seemed to have become part of the furniture. They were there, week in, week out, looking rather flat and listless in their tank, climbing over each other when they moved about. I did some reading up from the library and my own books, and eventually established that they were Gerrhosaurus major, aka the Sudan Plated Lizard, mostly found in southern Africa. Some books hinted they were a bit problematic. I thought about it some more, but found myself always going back to look at them.

Eventually it turned to autumn, and thoughts of Christmas loomed. I plucked up courage and asked my wife if I could have an early Christmas present, then went and asked the assistant manager, a genial chap called Mick, if he was open to offers for the two plated lizards. He was quite ready for someone to make him an offer as they had been there for some time, so we agreed a price for both the lizards, a 4'x1' glass aquarium with vivarium lid and the necessary accessories (heater, lights, etc). Thus we became the proud owners of two Gerrhosaurus major, whom we named Uther and Ygrane (after some Arthurian legend my wife had read).

To be honest the first few days were a disaster, partly owing to our inexperience and partly due to the limit to the shop's knowledge. The aquarium was long enough but it certainly wasn't wide enough, and you could tell immediately that the plateds felt as cramped in it as they had been in the shop's tank. They would restlessly run up and down, and Ygrane in particular seemed very skittish. I put a hide box (a large cardboard box) in for some security for them, but it virtually blocked the middle of their free space. I reasoned that since they were large and omnivorous they would want feeding twice a day (!), once with insects and once with vegetables, so in addition to being hemmed in they were also being invited to gorge themselves on food. Finally, despite the shop's assurance that they would not detect red light at night (geckos don't, after all), this turned out not to be the case, and they were being kept awake by a red bulb. Not surprisingly they were looking quite obviously stressed.

Feeling rather distressed by their behaviour, I phoned the shop and politely told them that the tank was too small and could we have a bigger one. They agreed and rang round, and to their credit gave us the money back on the aquarium when they could not supply one themselves. They also put us in touch with someone who could, a small company associated with a garden centre in Kent who produced a beautiful 4' x 2' wooden vivarium for about £150. This was heavy and a little awkward to fit into our estate car, but not as heavy as a glass vivarium of the same dimensions would have been. Once we got it home and wired it up, the plateds went in and we noticed the improvement in their behaviour almost immediately.

Sexing

Plateds are difficult to sex, since due to their armoured structure the vent is covered and no hemipenile bulges are visible, unlike some lizards. In this they resemble the monitors, although I am not sure whether pre-femoral pores are a guide. As a rule, however, females tend to be more timid and submissive than males, a fact borne out by our own observations over the past two years. Ygrane has remained largely skittish and nervous, often rushing into the hidebox when a human enters the room, whereas Uther is fairly unperturbed by the presence of people. Also, if food is placed in the tank, he will normally eat before Ygrane, even if the bowl is placed in front of Ygrane rather than Uther. At times he will actually eat food meant for Ygrane, so I normally try to feed her out of his sight. It has been suggested that Gerrhosaurus species can change sex in order to create a breeding situation, but there is no firm data as yet either way.

Feeding

Feeding plated lizards is quite easy, as they are omnivorous and like a wide range of food. For the first few years I operated a three times a week routine, usually every other day with a two-day gap between meals once a week. One feed would consist of black crickets (not too many of these as the chitin can be hard to digest), one of two pinkie mice each, dipped in calcium powder (eg Nutrobal), and one of vegetables and fruit, chopped and placed in a bowl. Since then I have discovered, at some personal cost, that a regular intake of pinkie mice in lizards that are not obligatory carnivores can lead to liver problems and a shortened life, although to my relief Uther and Ygrane do not seem to have been affected. Now I feed them both every three days, about three insect meals to one of fruit and veg, with the occasional treat of pinkie mice once in a blue moon.

Apart from black crickets, plated lizards will also take other commonly available invertebrate foods such as king mealworms and locusts, which they especially like but which are a bit expensive (you can breed them yourself but it takes time and dedication).

The best ingredients for the veggie dinner are paw-paw fruit (also known as papaya), water cress or mustard and cress, and one of the following: mixed vegetables (peas and carrots, normally thawed from a bag in the freezer), a chopped up strawberry, a couple of leaves of kale or spinach, and a few slices of ripe mango or banana. Note that kale, spinach and banana should only be given sparingly, as the first two items containing an oxidant-binding substance and the third is quite fatty for reptiles, although they love it. A bowl of water should always be available (not too cold).

Tameness

One of the best features of plated lizards is their tameness, at least with the males. We soon found that if you opened the sliding door of the tank, Uther would often come up to the opening and try to climb out, often onto your arm. In the beginning he was insatiably curious about his new keepers and would scramble up my arm and even onto my head, interesting behaviour for a non-arboreal lizard. He is now very tame and will either sit on my lap for about five minutes or climb up onto my shoulder and sit looking in the same direction as me for quite a while until he decides to go for a walk instead. Unlike most lizards he shows no resistance to having his head gently stroked and normally only struggles if he has other plans, which usually involve walking around the more inaccessible parts of the study. Ygrane is still quite nervous and often flees into the cover of the hidebox as soon as anyone walks into the study, and frantically resists any attempts to pick her up. This male/female difference was confirmed to me by Stella Quayle at the reptile zoo in Tatsfield, who said that male plateds are normally much tamer. Nevertheless, although Uther is the more active one, I have regularly seen Ygrane reach a peak of activity in the afternoon, when she stands on her back legs and tries for some reason to jump up and catch hold of one of the UV cables in her claws.

Things to watch out for

If you keep plateds, there are some behaviours you should be aware of to protect your pets. Firstly, don't be deceived by those legs which look rather short in comparison with the rest of the body. Those legs are powerful. Once Uther was sitting on a flat surface normally when for some reason he decided to jump. Without standing up first he actually managed to propel himself a few inches up into the air and forward, rather like a Harrier jump jet taking off. He also has a clever knack of being able to climb vertical faces by squeezing into a narrow gap between a wall and a heavy object next to it, using the surfaces to support himself while he forces his way upwards using his legs. As a variant on this trick, he also climbed up the back of the stereo unit once using the various cables that were dangling much in the same way as a mountaineer might use ropes. On a couple of occasions he has reached a height of about three feet off on the ground - again, not bad for a ground-dwelling lizard.

Those powerful legs also make them fast, so don't underestimate their ability to run. Once I was in the front bedroom when I realised that they were both out with the study door open. I raced to close it, but too late - two brown blurs shot past me in the opposite direction and disappeared under the double bed. That brings me to their next cunning trick - they like to wedge themselves into any convenient place which is nice and snug. This is part of their normal behaviour in the wild, as they like to burrow between rocks and, rather like the North American chuckwalla, seem to be able to fix themselves almost immovably in place. We had quite a few retrieval sessions from under that double bed, which normally involved a lot of physical contortions on our part and sometimes up to an hour's effort before they were both safely back in the tank. It goes for all herps generally - never leave any gaps where they can squeeze through and beyond your reach. It especially applies to plated lizards. One final thing that needs mentioning is that Uther at least is tremendously good at hiding. Herptiles generally are very quiet creatures owing to their generally low metabolic rate, but plateds seem to be the original stealth lizards. Once they find their place of retreat they can remain silent and concealed for hours, possibly mentally chuckling while you frantically pull the room apart looking for them. Uther has managed some brilliant tricks in the past, and not just hiding in accessible places like the hollow under the bookcase either. His piece de resistance must have been the time he actually hid in an A4 file by calmly sliding under the stiff cover, resting on top of the leaves. That A4 binder was sitting in front of me all the time and I looked everywhere else before I found him.

Bathing

Gerrhosaurus are not aquatic reptiles by any stretch of the imagination, but one thing they do seem to appreciate is a dip at reasonable intervals. This either involves placing a receptacle of water in their cage, for example a baking tray (clean or unused), or else running a shallow depth of water in the bath or bathroom sink and letting them soak in it for about ten minutes. The water should be tepid, about the same temperature as an African stream on a typically warm day should be. They seem to appreciate it, although they don't swim or submerge themselves in the same way as many monitor lizards, for example. Perhaps it helps around the heavily protected cloaca region, or keeps that armoured exterior supple. Interestingly enough Gila lizards, who also have a tough outside, come from desert regions but in captivity like to soak. Don't leave your bathing plateds in for too long if you are bathing them outside of their tank. I dry mine off with an old towel from the neck downwards and then put them straight back into the tank to bask. Another thing worth noting here is that unlike a lot of reptiles, being placed in water does not seem to induce Gerrhosaurus to defecate. But it is probably worth cleaning the sink and certainly the bath out after they have been bathing.

Health

It has been said that some keepers find the plated lizards somewhat problematic healthwise, but I have not found this to be the case. Rather, it seems that because the majority of them are wild-caught and imported, they carry certain things which crop up in captivity which need to be dealt with. I have taken them to the vets for treatment twice, both times for ectoparasites (basically internally-dwelling creatures, which virtually all animals in the wild carry). The first occasion was quite memorable, when I went in one morning to see what looked like several bits of soft white noodle with flattened heads floating in the water bowl. I was horrified, as I surmised correctly that this was some sort of worm. Our vet at the time (who incidentally is very good with reptiles - pity more aren't) confirmed that these were bits of a tapeworm. Treatment involved giving Uther and Ygrane some sort of Flagyll. If I remember correctly, they had one oral injection on the first visit and a follow-up a few days later, which cleared the problem up as no more proglottids (bits of tapeworm) were seen again.

The second occasion for medical attention was when I noticed that their stools were getting rather smellier than usual, almost offensive, which is very unusual for plateds despite their herbivorous diet. The vet took a faecal check and confirmed the presence of some sort of malignant protozoan that was dealt with in the same way, ie oral injection. Incidentally, something else that I have found is that lizards in general don't like things being forced into their mouths, and especially plated lizards. Dr Jon's description of the plateds changed within the space of a few minutes from "handsome" to "evil creatures" as he tried to force the plastic syringe past their rigidly closed mouths. Even at home being treated by their own keepers, Uther yielded a little more readily but Ygrane did not. In fact the first time we tried the oral method, the air was suddenly filled with a pungent smell as she voided her cloacal contents in protest (that was one pair of jeans straight into the wash). But again the medicine proved speedily effective, and since then we have had no problems with them.

Their shedding takes place a few scales at a time, most of which seem to be shed with a little exercise each day. A UV light is mandatory for these reptiles to simulate their near-equatorial environment, and I keep the temperature up at the warm end - possibly about 90 (the thermometer doesn't go high enough) over the basking rocks at the hot end, which in a 4ft tank gives a temperature in the low eighties at the cool end. The automatic timer turns off the lights between 9.00 pm and 8.00 am, which allows the temperature to drop 10-15 degrees as it would in their natural habitat. I think plated lizards are reasonably resilient given the correct temperature and lighting, and if you keep the tank clean. I have experimented with both pine chips and newspaper. Newspaper is easy, but paradoxically I am considered going back to pine chips because it is almost impossible to remove faeces from newspaper with the result that after just a few days you have a very messy substrate. Pine chips at least allow the removal of waste, as even urine in most lizards is passed as soft white urates that quickly dry out. Shortly I am going to try a sand substrate as I think this may resemble the conditions more naturally found in the wild.

Breeding and the Relationship of a Pair

I think it is fair to say that Uther and Ygrane's thoughts turned to breeding before we had considered the possibility. One day I was absolutely astonished to find two large, cylindrical white eggs in the tank, one outside and one inside the hidebox. In a frenzy we drove down to the petshop to get some vermiculite, a thermometer and another heatmat and thermostat, and then rushed back, only to find Uther running around in the tank with the remains of an egg hanging from his jaws. In our 20-30 minute absence he had destroyed them both. I know lizards generally are not supposed to be attached to their young nor even to protect their eggs, but Ygrane seemed very withdrawn for about a day after this and snappy towards Uther. However, a few months later two more eggs appeared, and since then they have been fairly regular, about every four months or so. Unfortunately my home-made incubator has been unable to prevent the collapse of those eggs which we have managed to rescue, so recently I invested in a commercial one. Watch this space for further details.

The intra-lizard behaviour of a pair of plateds is itself quite interesting. I have not seen much in print (if anything) about their life and sociability in the wild, but Uther and Ygrane get on very well together. Often if Ygrane is not disturbed she can be seen laying next to Uther on the same basking rock (we provided two large ones for them), when there is quite enough space for them both to remain apart. One action of theirs which I suspect is linked with mating is a strange biting motion made by both lizards. One of the lizards will be resting, and the other will approach it from the side, clamp the other lizard's neck in its jaws and make two or three biting motions with its jaws. Whereas one would expect the recipient of this behaviour to snap back, instead it is apparently ignored. Mating itself appears to be less brutal than among some other lizard species.

Community Cages

In 2010 I made some adjustments to my living arrangements, and subsequently to those of the plated lizards. Up to this point I had been keeping Uther and Ygrane in a 4' x 2' x 2' cage, and a Gerrhosaurus validus (Giant Plated Lizard) called Guinevere together with another plated lizard, Dorothea, in a 6' x 2½' x 2½' cage. Originally this latter pair had been a trio, but their companion Hermann (another plated lizard) passed away after a couple of years in captivity, which to date has been my only loss among this species.

Magazine articles have suggested that different Gerrhosaurus species of similar sizes can be kept together, and indeed do live together among rocks in the wild. My initial observations of Guinevere and Dorothea seemed to suggest that Dorothea was definitely the submissive partner in the relationship, and that sometimes Guinevere would chase her for apparently no other reason than a certain playfulness, since I never saw her actually injure or attack Dorothea. Guinevere herself is fairly indolent most of the time and in winter would actually rest in her hide for several weeks, presumably only coming out to drink, so Dorothea still had the freedom of the cage much of the time. Nevertheless I was on the point of considering whether or not to put her in with Uther and Ygrane instead.

My rearrangement of the reptile cages in autumn 2010 was somewhat disrupted by the runners for the glass doors of Uther and Ygrane's tank coming out, thus rendering the doors useless. While fixing the runners, this meant of course that Uther and Ygrane had to be housed in a different cage. Since they couldn't go in with Anthony and Cleopatra, the two much smaller Gerrhosaurus flavigularis (Yellow-Throated Plated Lizards), the only other option was to put them in the large 6' tank with Guinevere and Dorothea. Although Uther by nature is a very calm lizard, I confess I had my concerns and thought this would probably be a very temporary arrangement.

To my surprise having the three G. major and one G. validus in together appears to work quite well, and seems to have balanced the personalities of all four lizards, but especially Ygrane and Dorothea who until then could be fairly flighty. Now I find that during the early to middle parts of the day all four will be out basking, although the overall impression is that Uther and Guinevere remain somewhat dominant or at least first ammong equals. The most telling evidence comes at feeding time, however, especially when a bowl of paw-paw is offered. I have noted all four of them gathering around the bowl to eat at the same time, strangely reminiscent of Komodo Dragons assembled around a large carcass. One particular instance I remember is during one of these fruit orgies, when Dorothea noticed the remains of some paw-paw on top of Guinevere's head and carefully licked it off her, the latter not seeming to mind or notice. Even when insects are offered there seems to be no squabbling, each lizard simply consuming as many as it feels like before desisting, without any chasing or harassing of the others.

It may well be that such a community setup replicates the behaviour of some groups of these lizards in the wild. The drawback, apart from the space required (remember this is a large cage - I had to disassemble it with a power screwdriver to transfer it into a different room), is that if breeding is intended then it may not always be possible to tell when eggs are found the identity of at least one of the parents.

Conclusion

In conclusion, I have had these lizards now for over ten years and never grown tired of them. They are friendly, relatively easy to look after and do breed in captivity. I recommend them to anyone who is willing to spend a reasonable amount on the initial outlay to get them set up right.

Summary of Gerrhosaurus requirements:

Vivarium size: Ideally at least 4 ft by 2 ft for a pair, best with sliding glass door. Up to four can live in a larger cage (say 6 ft by 2 ½ ft)
Heating: Thermal gradient from 70-75 degrees to 85-90 during the day, dropping about 10-15 degrees for 10 hours or so at night.
UV Light: Yes
Food: Omnivorous and easily satisfied: Insects: crickets, both brown and black, mealworms, occasional waxworms, locusts. Vegetable matter: cress, paw paw (aka papaya), thawed veggies such as mixed peas and carrots, mango, strawberry, limited amount of spinach, kale, banana and occasionally low-fat dogfood: pinky or two occasionally.
Water Bowl should always be present: like bathing in warmish water if given the opportunity.
Handleability For a lizard, quite high: as a children's pet, possibly suitable for 10 years upwards if parental encouragement given. Don't forget rules on handwashing afterwards.
Health Fairly robust, but do watch out for parasites in wild-caught specimens. A precautionary visit to a reptile vet may be worthwhile.
Initial outlay (excluding the lizards themselves) About £200 for the tank/vivarium and the heating equipment. The lizards themselves will probably cost about £40-50 each. Buy from a reputable shop or dealer as wild-caught imports do vary in health.


Bibliography

Staggeringly, there is virtually nothing in print dedicated to Gerrhosaurus. The only books that mention them are those dedicated to lizard-keeping (and hence a large number of species) in general, and some of the brief information is not terribly helpful. Perhaps the best is the Bartlett's A-Z of Lizard Care (Barrons). Richard Wynne's Lizards In Captivity (TFH) is also reasonable given that it was written over 10 years ago. TFH themselves promised us a book dedicated to Sungazers and Plated Lizards for a couple of years, but haven't delivered as yet. Their herpetological magazine Reptile Hobbyist had an article by Jerry Walls (Dec 1998) about Plated Lizards which was quite good, although it contained a couple of things that ran contrary to my own experience. (Having said that, I think Jerry Walls is one of the best herp writers around). As I believe this is one lizard that can be kept responsibly by a large number of people, it seems a pity that it is not more widely publicised, especially when compared with more popular but problematic reptiles.

More recently I have been keeping an index of Gerrhosaurus articles, as magazines such as Reptilia have carried informative material on them.

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