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An Introduction to Geckos

Some of our most familiar and desirable of reptile pets, such as the leopard gecko and the brilliantly-colored day geckos, are members of a fascinating family of lizards that I would like to introduce today.

The 1,050 or more species of geckos comprise the second largest of lizard families, the Gekkonidae (the largest is the Scincidae, or skinks). They range throughout the world, reaching their greatest diversity in desert and tropical habitats. “House geckos” of several species follow human habitation and are widely transplanted, including into the southeastern USA. Geckos range in size from the various Shaerodactylus species, some of which are full grown at 1.2 inches in length, to the New Caledonian giant gecko, Rhacodactylus leachianus, a bulky creature that tops out at nearly 15 inches. Several other species, now considered extinct but which may possibly still survive in Madagascar’s forest canopy, reached 24 inches in length.
Adult Leopard Gecko
Geckos generally lay 2 eggs, although some bear live young. Arboreal types often glue their eggs to tree branches or building walls. Most are insectivorous, but many take nectar and over-ripe fruits as well. The voracious tokay gecko, Gekko gecko, consumes nestling birds, small rodents and bats, snakes and other lizards. A number of species are highly endangered while others, such as the leopard gecko, Eublepharis macularius, are pet trade staples. Many have a long association with people, being welcome in homes for their insect-catching abilities and sometimes regarded as good luck symbols. Some years back, a store in NYC even rented tokay geckos for use as roach-control agents. However, the males’ habit of calling loudly (“Tokay-Tokay!”) at 4 AM and their pugnacious dispositions rendered the scheme less-than-profitable!

The ability of many geckos to climb sheer walls (even glass) and to run upside-down on ceilings was first recorded by Aristotle in the 4th century BC. Only recently has the secret behind this remarkable phenomenon been discovered. The toes of many species are covered with layered pads known as lamellae, which in turn support thousands of microscopic hair-like structures called setae. Their action against a surface sets up a weak molecular attraction known as the van-der-Waals force, and this, it seems, is the source of their unique method of adhesion. This phenomenon Tokay Geckois being studied with a view towards creating new adhesives for use in industry.

Members of this huge family have evolved startling adaptations to a number of basic themes. To cite just one example – depending upon the species, tails are used to distract predators (by disengaging from the body), plug burrows, extrude noxious secretions, create sound, communicate with others, convey stability while gliding, store food and grip branches.

Please pass along your gecko-related comments and questions. Thanks

If you have a special interest in geckos, you may wish to join the Global Gecko Association, or to visit their website for further information:
http://www.gekkota.com/

Until next time, Frank

25 comments

  1. avatar

    Hello- my youngest son would like a pet geko. is this a creatute that can do well on commercially prepared foods like dried mealworms, etc? i would like to avoid having to run to the local pet store every time we need live crickets. is there another reptile or anphibian that could also live on prepared foods, not live? Santa needs to know these things. thank you, scott boing sboing@tampabay.rr.com

  2. avatar

    Hello Scott,

    Frank Indiviglio here. This is my first Santa-related request, thanks!

    Leopard geckos and all other commonly available geckos require a variety of live foods. However, leopard geckos can usually be trained to accept canned insects from feeding tongs…this would be your best option if you decide upon a gecko.

    There are herbivorous lizards, but most are not suited for beginners – green iguanas reach 4-6 feet in length, dabb lizards require very high temperatures and UVB levels, etc. Bearded dragons are a possibility…they consume mainly plants as adults (insects when young), but many refuse to switch to a plant-based diet in captivity; they also require high temperatures and UVB levels.

    If you decide against trying to train a leopard gecko to tong-fed, my best advice would be to go with an aquatic salamander, i.e. Eastern spotted newt, fire-bellied newt or California newt. All are small, long-lived, feed on commercially prepared foods, require no UVB and are fine at normal room temperatures. They are not very handle-able however, due to their delicate skins, but will become tame and feed from the hand.

    African clawed frogs are extremely hardy, but and will get by in a filtered 10 gallon aquarium. These are much more responsive than the newts, really becoming “pets”, responding to owner when hungry, etc. and will even breed in captivity. As long as attention is be paid to water quality (changing the filter material, partial water changes), I would highly recommend a clawed frog. They readily accept commercially prepared foods and require no supplementary heat.

    Aquatic turtles and tortoises will thrive on commercial diets, but filtration, space, heat and UVB must all be considered.

    Please write in when you’ve narrowed down your options, and I’ll be happy to provide specifics as to terrarium size, diet and care for each.

    Best regards, Frank Indiviglio.

  3. avatar

    could a crested gecko be a possible reccomendation?

  4. avatar

    Hello, Frank Indiviglio here. Thanks for your comment.

    Crested geckos are an excellent recommendation; I plan to write an article in the future. Its strange in a way…such a unique creature, unknown even in zoos not long ago, but actually a fairly hardy captive in the right hands.

    Best regards, Frank Indiviglio.

  5. avatar

    Frank,

    I now have a question for your regarding leopard geckos and the much debated substrate. I’ve have 5 leopard geckos all who are adults, I have 3 in a 20g and 2 in 10g.

    Now, I’ve always used reptile carpet for them but it’s quite high maintenance to keep up with. In my 10 I’ve went ahead and switched those 2 over to Reptilte. It seems to get a mixed bag of reviews, what’s your experience with using sand as substrate with leopard geckos? Thanks for the info!.

    -Dave

  6. avatar

    Hello Dave, Frank Indiviglio here.

    Thanks for your interest and question.

    I’ve not had any problems keeping leopard geckos on sand, either in zoo exhibits or at home. I did tend to use finer grades, which have been shown to pass through the digestive tract easily.

    Zoo Med Vita Sand is particularly fine, and should not cause any problems, especially of you feed your animals properly and keep them well hydrated (see below). If you’d prefer to be extra safe, you can cover the sand with a thin layer of cypress mulch.

    Rabbit pellets, an old tortoise-keepers choice, can also be safely used with leopard geckos. They are inexpensive and clump when damp, thereby easing spot-cleaning. Geckos rarely swallow them due to the size and weight…those that are ingested have not been implicated in any problems. However, they will support fungus and mold when damp, so regular cleaning is very important (animals hailing from arid habitats are hard-hit by many molds and fungi).

    You can also place food items in a smooth, deep dish (this helps retain supplement coatings as well) or remove the lizards to a bare-bottomed feeding container.

    I have read of problems with sand impaction, but I believe that other factors may contribute and perhaps leave geckos prone to sand impactions. For example, adult crickets carry a good deal of indigestible material (wings, legs), and mealworm and wax worm exoskeletons are particularly high in chitin. These can slow the digestive process, especially if the lizard is not properly hydrated, making impactions more likely. Stick to sub-adult crickets and newly molted mealworms, be sure your geckos drink regularly, and offer them soft-bodied moths and other such insects and canned silkworms when possible.

    Thanks again for reading so many of my articles,

    Best regards, Frank Indiviglio.

  7. avatar

    Frank,

    Thanks for the prompt answer and reply, I guess I’ll go ahead and buy some more sand and move my other 3.

    All my herps seem to love silkworms, they just seem a bit on the hard side to get, other then the canned ones you speak of.

    I do have some more questions for you, however they are frog related so I will ask them in the appropriate forum!. :)

    Thanks!

    -Dave

  8. avatar

    Actually I do have another Gecko Q, do you happen to know much about the ‘Giant bent toed gecko’? I purchased one roughly a month ago, it’s a beautiful gecko. However, I’ve kind of been winging it care wise since I can’t find much info on it.

    It seems to only take water off the leaves and glass sides, but after far as eating he doesn’t show much interest in crickets. He will attempt to eat superworms but after making one lunge at them and missing it, it’s like he gives up!.

    I put a small pinkie in there just to see, hoping he would grab it up like my tokay. But again no interest! I’m getting a big concerned now.

    Thanks!

    -Dave

  9. avatar

    Hello Dave, Frank Indiviglio here.

    Thanks for the interesting question…I think many folks share your concern, as the bent-toed geckos are an interesting but problematical group, and there is a great deal of conflicting advice out there.

    So far, 115 species have been described in the genus Cyrtodactylus. The giant bent toed is often sold as the “New Guinea phase” of C. louisiadensis, but is actually a separate species, C. irianjayaensis (to further confuse matters, stores sometimes mix up the various species, but the aforementioned is the usual case).

    There are still many questions as the husbandry and natural history of the giant bent toed gecko. Over the years, I’ve had a number of little known species in this genus pass through my hands, and have found a few general principles to be of use:

    Give the animal as much space as possible, with lots of cover and places to climb (lacking toe pads, it cannot scale glass). They are very stress prone, but don’t always exhibit behavior signs as do many other lizards; disturb it as little as possible.

    Although likely mainly nocturnal, assume that in common with related species it requires UVB radiation, i.e. via a Zoo Med 10.0 bulb (others in the genus are very prone to metabolic bone disease). To cover all bases until we learn more, I suggest powdering all food with both vitamin/mineral powder and extra calcium (i.e. a 1:1 mix of Reptivite and Zoo Med Repti Calcium). Be sure that cool areas (72-75 F) are available in addition to a warm basking site.

    Many arboreal tropical geckos, Cyrtodactylus included, relish snails, and these seem to be an important source of calcium in the wild. You can use small garden or aquarium snails in available. Roaches nearly always stimulate related lizards to feed; they also respond to moths, beetles and other wild caught insects – it’s very important to try a variety of insects with bent toed geckos, as they do not easily switch food preferences. Try to collect insects or consider a Bug Napper Insect Trap. Leave food in the terrarium overnight, and try offering grubs, mealworms, wax worms and the like in cups suspended above ground.

    Please keep me posted, good luck and enjoy,

    Best regards, Frank Indiviglio.

  10. avatar

    Thanks for the feedback; I’m glad you found the information useful.

    Canned silkworms are much easier, assuming your animals will accept them from feeding tongs. Live ones that feed on a commercial diet are available (this saves time searching for mulberry leaves!) but they are a bit of work to find and culture.

    Looking forward to your frog comments,

    Best regards, Frank Indiviglio.

  11. avatar

    Hi Frank,

    And thanks for all the info on the bent-toed. I currently have him in a 20 long with a substrate of coco fiber and a fine mix of reptisand. Not to much, just enough where it’s visible in the mix.

    I have a lot of fake plants and cork bark in there and he basically hides all the time. Comes out at night and walks around until he’s spotted and darts for one of his hides. Funny thing is, if I reach in there sometimes he will come up my arm and just kind of hang out. He’s a very cool gecko, I will try that bug napper and see how that works out.

    I just would feel better if he would eat more often!. I’m going to try to get some live silkworms first and see how that goes. I have been dusting everything I put in there as well.. as far as crickets and worms.

    Well again! Thank You Frank!!!!

    -Dave

  12. avatar

    Hello Dave, Frank Indiviglio here.

    Thanks for the feedback, you’re very welcome.

    You might want to try providing more security by covering the back and 1 side of the terrarium with a dark cloth or solid aquarium background. Most animals settle in much more quickly when not exposed on all 4 sides…this is an old zookeeper’s trick, not used much today but very effective. Until he’s feeding well I wouldn’t suggest putting your hand in the terrarium unless necessary…the lizard climbing onto it could be for any number of reasons, but best to treat him as a display animal. Avoid turning on bright room lights at night if possible…a night-viewing bulb will help you to observe him during his normal activity period, and will provide night-time heat if needed. Bear in mind that stress is not always easy to notice in this species, but is a real concern.

    Any novel insect that you can offer would be worthwhile, including silkworms. You might wish to order a few soft-bodied roaches as well…orange spotted roaches are ideal, and less likely to escape than others (please see my article on Orange Spotted Roaches for more information).

    Enjoy and good luck,

    Best regards, Frank Indiviglio.

  13. avatar

    Hmmm.. I will give that trick a try, I’ve always read that those type of roaches are excellent feeders. Perhaps, I’ll see what I can do about starting a colony.

    Must not be to bad as I’ve seen many now start to do it. I’ve feed one before to my T. blondi
    and it took without hesitation, same for my C. crawshayi.

    Had never tried with my geckos though, will give it a shot.

    Thanks!

    -Dave

  14. avatar

    Hello Dave, Frank Indiviglio here.

    Thanks for your note. Orange spotted roaches are, as you say, also great for spiders. I’ve used them for local spiders as well, and mantids, centipedes, scorpions, fish and all sorts of insectivorous herps. Soft bodied so more widely accepted than hissers and some others, and less likely to escape than some. They take a variety of foods so it’s very easy to nutrient-load them, thereby providing your collection with a more nutritious food item. I gave a colony to the Brooklyn Children’s Museum last year and they now use them as a staple, in place of crickets.

    I’ve found that roaches often spark reluctant feeders. Makes sense, in a way – there are about 4,500 roach species described so far, and in many tropical habitats they are one of the dominant insect species, and comprise the bulk of the diet of many insectivorous animals, especially those which are nocturnal.

    Please let me know how you make out.

    Best regards, Frank Indiviglio.

  15. avatar

    Well I got some dubia’s today at the bug show we had at the Natural History Museum of Los Angeles. I’m hoping the bent toed gecko will find these appealing. I know everything else I have will!. Will keep you updated. Thanks..

    -Dave

  16. avatar

    Hello Dave, Frank Indiviglio here.

    Thanks for your feedback…I’m interested to hear if the geckos take the roaches, please let me know.

    Best regards, Frank Indiviglio.

  17. avatar

    Hi Frank,

    Question for you regarding one of my leo’s, I just noticed over the past couple days that his jaw is starting to get a small lump on it. Almost looks like a pea size ball on the right side, I’m hoping this is not Stomatitis.

    I have them all on sand, and I’m hoping this is not the culprit. Feel bad as this is truly the issue I’ve never had with my leopard geckos. Thanks!

    -Dave

  18. avatar

    Hi Dave, thanks for your comment.

    Unfortunately, Frank’s away right now on emergency surgery. We hope to have him back this week, at which time he’ll address your question. Sorry for the delay.

  19. avatar

    Hello Dave, Frank Indiviglio here. Nice to hear from you again. I apologize for the long delay in responding to you…an emergency surgery put me out of commission for a time.

    It’s very difficult to diagnose a lump as they can arise from such a wide variety of causes and each may require a different treatment. I think a visit to the veterinarian for a radiograph or perhaps biopsy would be your best bet.

    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  20. avatar

    Hi Frank,

    Wondering if you have any experience with the Halmahera Giant Gecko? I’m wondering if there is a difference between that species and the G. Marginata? I always see people advertising them as one or the other.

    Very confusing.. I actually can’t seem to find much information on either of the two. Are they a large gecko? Thanks for any information!

    Regards,

    -Dave

  21. avatar

    Hello Dave, Frank Indiviglio here.

    Well, you’ve certainly picked a troublesome group to focus on! The animal usually sold in the trade as the Halmahera Giant Gecko is most commonly Gehyra vorax, which actually does not occur on the Indonesian Island of Halmahera. It instead inhabits Papua New Guinea, Vanatua, Fiji, Tonga and the Society Islands. Its local name is the “Voracious Dtella”.

    A similar species does inhabit Halmahera (and the Moluccas), but it is difficult to determine if this animal is making it into the trade. Both lizards vary in appearance naturally, and might interbreed in captivity. The most common species on Halmahera (there are also others in the genus, I believe, on this island) is G. marginata. Some dealers label this animal as the “Moluccan gecko”, but I honestly cannot be sure as to the actual ID from the photos I have seen.

    Even the taxonomic notes of the American Museum of Natural History, which are usually quite detailed and lacking in generalities, state that both of the above species may be allied to or encompassed by G. oceania!

    So you have your work cut out for you! Gecko enthusiasts are a quite intense lot in general…perhaps you can find out some locality info. If so, please feel free to send in some details and I’ll help if possible.

    Good luck and please keep me posted.

    Best regards, Frank Indiviglio.

  22. avatar

    I just recently found a spotted dtella in my yard what does he need to live in a terrium

  23. avatar

    Hi Kelly,

    Sorry, not recognizing the name..perhaps a typo?

    Best, Frank

  24. avatar

    Crested geckos are one of the best reptiles to have. With a quite strange look, easy disposition, and reasonable activity levels I believe that they will appeal also to non reptile hobbyists, and might bring more people into the hobby. They are very adaptable, omnivorous and not shy at all. I have a two year old male for one year and somewhat more and he is fantastic. Also it is very strange how a new caledonian reptile, that was thought extinct from 1866 or so, got accidentally rediscovered only in 1994 and now features so commonly in the reptile trade, that it might displace even the leopard gecko.

  25. avatar

    Yes, there are many examples like this, very strange, especially to those of my generation who began keeping reptiles 50 years or so ago. Native US species (and mammals, birds) were much more common, along with certain exotics, but others (including bearded dragons!) were rarely seen even in major zoos!

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About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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