Teeth, evolution ramblings and Caiman Lizards….

Teeth come in a huge array of designs and forms, and looking at species-specific variations can tell you alot about an animal’s lifestyle and diet. In the boa above several rows of small sharp, rear-facing teeth allow the snake to grab it’s fast-moving prey and hold onto it as it struggles in the split-seconds before it coils around the prey to constrict and suffocate it before swallowing whole. On the other hand, the lizard mouth below shows a highly specialised dentition designed for crushing snails and other hard-shelled molluscs. This is a specialist snail feeder, a South American Caiman Lizard (Draceana guianensis), possessing small rounded bead-like teeth and incredibly strong jaws for crushing it’s rather more slow-moving prey.

Both animals were brought to clinic recently, unfortunately the lizard was found dead and came for a post mortem which revealed head trauma with secondary infection as the cause of death. Interestingly though, the post mortem exam also showed a condition known as hepatic lipidosis or fatty liver, associated with a captive diet of dog food. These lizards are difficult to provide for in captivity, getting them to eat in the first place and then maintaining a snail-only diet in the long term both being tricky. Because dog food contains much higher carbohydrate and fat content than their wild diet, and their relative inactivity compared to wild conditions, the liver converts excess food into fat which can lead to fatal complications. I am currently working on providing a better alternative animal protein based diet to prevent such complications in the remaining lizards in the collection. This problem is commonly seen in large carnivorous reptiles in captivity, specifically monitors and tegus which have evolved to range over very wide areas in the wild in search of food items of relatively low nutritional value.

Look away now if you’re squeamish, but here is the liver removed form the above specimen. It is grossly enlarged, has rounded rather than sharp edges to each lobe, is light yellowish brown in colour instaed of dark red/brown as normal, and has a marbled appearance in closer detail. When removed it was extremely friable, splitting easily and when sectioned the scalpel blade sliced through it extremely easily almost peeling the organ apart. These are all pathological signs of hepatic lipidosis which we would have missed had the owner not agreed to a post mortem examination. Hopefully we can reverse these changes through a modified diet in the remaining lizards.

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3 thoughts on “Teeth, evolution ramblings and Caiman Lizards….

  1. Hello Sean, do you know if the same problem does appear in captive Gerrhosaurus major ? Mine are fond of wet dogfood, I try to mix with cooked dog vegs (they would be omnovorous) and low-fat freshwater fish (Atherina boyeri), but they quite dislike them… They eat large mealworms larvae, but not roaches, that remain roaming in their box. Coudl you suggest any better and not too difficult to provide food items?

    • Culturing your own snails might be a good idea. I’m not a fan of feeding commercial dog food as it is quite fattening and often contains grain based carbohydrate too. A more pure protein source such a scrambled egg, or occasional supplemented minced meat (turkey or beef) in small quantities would also be more acceptable.

      • thank you Sean, I could try altough I’m concerned with possibile parasites within snails, I rear as ”pet” Achatinas and some other but I am not sure about how to grant a ”hygienic” food, still more if I would colture some local, wild snails; any suggestion would be welcome!
        As to canned foods, I ‘ve found a chicken meat product, extremely low in fats ( 0,5 % ) ; it contains 77 % water, 16 % proteins, 0,1% fibers, 0,5 %minerals / ”ashes”. Sadly it is 99% chicken breast, but 1% rice; I don’t know if this low level could be still of concern. Yet, while it’s very appreciated by my Novoeumeces schneideri, Gerrhosaurus are not fond of it and prefer more ”tasty” foods…. I could use the latter as ”flavouring” anyhow, provided the basic items are healthy for them.

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