UPDATE:
I did raise some babies on dry crested gecko diet with no apparent ill-effects after an initial month of feeding wet crested gecko diet.
I did not, however, hold onto them much longer past maturity and moved them on to other keepers.
Now I'm wishing I should have because over the last couple of years I've been doing more research on nutrition.
About a year ago I adopted a cat. This being my first "pet", I did as much research on nutrition as I possibly could after noticing that many of the older cats at the shelter had chronic or acute health issues due to diet/lifestyle.
Of particular interest to me and possibly other cat owners on this site was something I read in the Nutrition Research Council's "Nutrient Requirements of Dogs and Cats" (the book with which AAFCO (US) and FEDIAF (EU) base their complete and balanced diet recommendations).
The book stated that cats, having evolved as desert animals and consuming food with a high water content, have a low thirst drive.
It goes on to say that cats (and dogs) fed meat that was 67 - 73% moisture were able to maintain a good water balance without additional water, and those cats fed meat desiccated to 61% moisture were not able to maintain good water balance (dehydration), probably due to the amount of water needed to excrete urea.
Cats are slower than dogs to initiate drinking or to drink enough for complete rehydration than are dogs. This leads to chronic dehydration for cats on all dry or mostly dry diets which leads to urolith formation (stones) in the urinary tract. Dry diets typically contain only 10% moisture while canned foods typically contain 70-80% moisture.
Dry foods also tend to cause obesity in my opinion due to the cat consuming more calories than the equivalent weight in canned food and the higher carbohydrate content of dry foods over canned food.
Once I brought my kitten home I immediately weaned him off the dry food which he really liked from the shelter. He turned his nose up at it for a over a day but eventually caved. Now I only feed canned cat food with some occasional raw ground rabbit. I do offer him water on occasion but have never witnessed him drink.
What does all of this have to do with crested geckos?
Not much really, crested geckos are not cats and crested geckos do not come from deserts. Yet, I still feel compelled to follow some of the nutritional advice I'm applying to my cat's diet to my crested geckos' as well seeing how neither evolved to eat foods containing 10% moisture.
I do know that most reptiles reabsorb water in the colon from liquid urine produced by the kidneys which decreases the need for water.
However, it is also true that reptile kidneys need a lot of water to excrete uric acid since they are unable to produce liquid urine more concentrated than their bodily fluids due to the lack of the Loop of Henle which is present in birds and mammals and is a structure in the kidney that allows the production of concentrated liquid urine via electrolyte pumps.
To combat the large volume of water needed by the kidneys, reptiles reabsorb water in the colon (most of them).
So perhaps it is even more imperative that out reptiles be properly hydrated than our mammals.
Does anyone know if cresteds have a low thirst-drive?
I think until I find that out I will be reincorporating water into my crested gecko diet to closer mimic the moisture content of their natural diet. The peace of mind in knowing that they are getting more water will help offset the additional cost of feed, which isn't too bad anyhow as I now have a good feel for how much wet crested gecko diet they will eat in a given time.
If I'm able to determine the thirst drive of any reptiles I'd be happy to share the results with you all.