Herbivorous Lizards?

I want to get a pet lizard that does not require going to the pet store every week to purchase crickets. I hear about plant ingestion lizards, and was told to administer them a try. I want to get a justly small lizard that can be taken out and held, and doesn't run quickly. I do not want a green iguana. I looked up the blue- tounged skink, and I thought that would be pretty accurate. Are they fast lizards? Do they bite? Can they be held? I also saw that they be around $200. Is that a reasonable price for this skink? Are in attendance any cheap ($15-60) herbivorous lizards? If not, are there other plant- intake skinks that aren't so expensive?

Thanks for the help.
Answers: Uromastyx are dutiful. The common ones run for nearly $60. Don't need crickets whatsoever.

Blue-tongue skinks due require some protein within their diet. An occasional cricket, mealworm, or even cockroach is necessary. Feeding live food isn't as unpromising as it sounds. The don't usually bite, but anything with a mouth can bite. They can be held repeatedly, very handleable lizards. They do come beside a high price sticker. I bought mine for $90.

Fire skinks are a smaller and somewhat cheaper alternative.
Introduction
Totally herbivorous lizards are found in three disjunct regions: (1) the New World tropics northward into the Mojave Desert of the SW United States (all the Inguaninae but two species), (2) the Near the Middle East from North Africa to Southwest Asia (spiny tailed agamids Uromastyx); and (3) the tropical Far East surrounded by the Fiji Islands (the banded iguanas Brachylophus), the Philippines and Indonesia (water lizards Hydrosaurus) and the Solomon Islands (giant skinks Corusia). They are found on islands as well as continents, contained by predator-filled to nearly predator-free environments, in xeric (most), mesic, and hydric habitat, and they include both oviparous and viviparous (only Corusia) forms.

Perhaps the most unique all your own of the lizards of the sub-family Iguaninae is their success at herbivorousness. Unfortunately, complete, reliable information on diet and feeding traditions for most of the iguanines are not available; most of the published information is only anecdotal, and, contained by some cases (see below), clearly misleading. Intrigued by my own observations that the ground iguana, Cyclura carinata, is almost totally herbivorous from hatching through middle age (a weight selection of 15 to 1900 g), I began examining lizard herbivory surrounded by terms of diet, feed habits, feed strategies, and adaptational correlates (both morphological and physiological). By looking simultaneously at all of these aspects of herbivory, I hoped to better fathom out the mechanisms involved surrounded by its evolution in lizards.



Diet
For purposes of this discussion I consider as "truly herbivorous" (i.e., on the far right of the [carnivory-omnivory-herbivory] continuum) singular those species whose diets include essentially only flora (whether fruit, flowers, seeds or foliage) throughout the year.

Many species roughly called "herbivorous" are probably facultative herbivores at best, and more plausible, simple omnivores. Based on the literature and my own dissections of several hundred lizard species, [most] such forms [species names omitted] although commonly termed herbivorous contained by the literature are clearly not true herbivores. In fact, by my definition, the solitary totally herbivorous extant lizards are the iguanines (+/- 30 species among the Iguanidae), the genera Uromastyx, Hydrosaurus among the Agamidae, and Corucia zebrata contained by the Scincidae.

I have also found no idea for earlier speculations that the iguanines Amblyrhynchus cristatus, Cyclura nubila, Iguana, and Dipsosaurus dorsalis, and the agamid Uromastyx hardwicki exhibit an ontogenetic shift from carnivory to herbivory [eating animal protein as juveniles, adopt an herbivorous diet as adult]. Most of these suggestions were base: (1) on diet information from captive lizards, or (2) on anecdotal area observations. In fact, of adjectives the true herbivores I have dissected, individual the iguanine Ctenosaura similis showed any indication of an omnivorous juvenile diet. Further field study will be compulsory to establish quantitatively the extent of this omnivory by size and season (for C. similis). I thus conclude that an ontogenic shift from carnivory to herbivory is not usual surrounded by lizards truly herbivorous as adults, and further, that the documentation of such a transition (as appears to be the case for C. similis) will at best be the tremendously rare exception to some extent than the rule.



Feeding Ecology
Other than Auffenberg's work, studies of the ecological aspects of feed in herbivorous lizards hold received little attention. However, it is known that herbivorous lizards spend the majority of their hustle and bustle cycle resting, not feeding or foraging as do most carnivorous lizards or mammalian herbivores. Moberly estimated that Iguana spends 90% of its time resting, and Beverly Dugan estimated that like peas in a pod species spent 96% of the day desk and only 1% feed.

Despite the apparent bounty of plant food, availability of food resources may be the primary limiting factor for populations of many iguanine lizards species. For example, contained by Columbia, Mueller has shown that green iguanas inhabiting strongly seasonal habitat are smaller than those in smaller amount seasonal habitats.

Rand have suggested that food may be limiting to Iguana iguana in notably seasonal tropical habitats with the sole purpose during part of the year. Further, even during times of maximum primary productivity, i.e., times when soaring quality foods (e.g., fruits) are most plentiful, lizards can only devour and assimilate as much as their digestive machinery can process. Because of the low relative metabolic rats and daily fluctuations within body temperatures, this machinery may resourcefully limit vitality intake even at maximum efficiency.



Digestive Physiology
Other physiological aspects of lizard herbivory hold received some attention. For example, digestive efficiencies of carnivorous lizards are known to swing typically from 70 to 90% and to exceed significantly those of herbivorous lizards, which normally stock from 30-70%.



Trophic Adaptations
All true herbivorous lizards, regardless of family, are specialized surrounded by that they all share one significant morphological familiarization (and a suite of associated physiological and ecological ones) found within no other living lizards: all hold a distinctly enlarged, partitioned colon. All iguanine lizards except Amblyrhynchus cristatus [whose valves differ from the others singular in distance from the ground of the folds with no true valves] possess from one to eleven transverse valve in the proximal colon. Valves are of two kind, circular or semilunar, and circular valves (if present) other occur proximally to semilunar valve. There is no ontogenetic change contained by the number or the kind of valve.

Colons of unknown species can nearly always be allocated at least possible to genus, based solely on morphology of that organ.

Perhaps the most intriguing item about iguanine colic instability is the significant linear relationship between number of valves and indicate body size for interspecific comparisons. The larger the species, the more complex is the colon (i.e., the more colic compartments present).

The partitioned colon surely slows the passage of digesta through the gut, and relative absorptive surface nouns (for water and nutrients) is indeed increased. But the presence of tremendously dense nematode faunas (and presumably bacterial and protozoan populations) in the everyday cecum of all these herbivorous lizards suggest that they provide crucial microhabitats for colic (cellulytic?) symbionts. These nematodes (families Atracidae and Oxyuridae) have direct duration cycle, and eggs are likely ingested during substrate licking, geophagy or coprophagy--behaviors frequently observed surrounded by these lizards. Significantly, these heavy worm burdens are typical of herbivorous lizards, where on earth as such burdens are not found in omnivorous or carnivorous lizards.

The tremendous nematode densities contained by healthy lizards suggest they are not parasitic, but fairly commensalistic, or perhaps even mutualistic. Potential roles for these nematodes include (1) the simple mixing and powered breakdown of vegetation, effectively increasing the surface nouns of digesta particles; (2) the production of useable leftovers products (vitamins, cellulose, volatile fatty acids?); and/or (3) the regulation of the composition and/or abundance of colonic microbes (on which some nematodes are set to feed).

Gastrointestinal tract modification for symbiont culture is also the norm in herbivorous organisms that own previously been studied. Colonic partitioning surrounded by herbivorous lizards is thus by no means innovative. What is surprising is the lack of attention it have received especially since it appears to be the one adaptation essential for a lizard's completely herbivorous existence.



Body Size
True herbivorous lizards share another observable character. Excluding the varanids (which are enormously specialized carnivores), they are the largest extant lizards. [Hypotheses which explain the adaptive significance of body size and herbivory include] the greater mechanical strength [needed] for reducing undergrowth for consumption (although there is no mastication); the benefit of reduced predation and competition; the advantage of intake easily to be had foods of medium to poor trait (i.e., plants) rather than large quality food items (i.e., insects) more energentically costly to pick up (since metabolic rates are relatively lower in colossal lizards); and the advantage of greater thermal inertia, allowing the preservation of elevated body temperatures and facilitate the digestion of vegetation. Each of these theories relates selective advantages which without question accrue to large, herbivorous lizards, but none appears to fully explain the body size-herbivory relationship surrounded by these lizards. I here extend another hypothesis which I think more satisfactorily explains the body size-herbivory correlation and permits speculation on the evolution of these characteristics within lizards. I believe that the anatomical, physiological, and ecological characteristics of the gastrointestinal tract are the most far-reaching determinants, not only of herbivorous capability, but also of body size in these lizards.

Previous studies on both lizards and turtles enjoy shown that body size may be significantly related to resource availability. Analogously, I believe that the evolutionary increase in colon complexity have increased resource usability (not necessarily availability!), and thereby energetically permitted increased body size. Thus colon modification (and the diversification and increase contained by the intestinal flora and fauna), these herbivores have be able to grow to larger sizes, and thus more fully gain other selective advantages, such as reduced predation, metabolic and thermoregulatory benefits.



Discussion
I believe that the iguanines, Uromastyx, Hydrosaurus and Corucia are much more specialized that collectively realized. Each have a relatively large body size and a modified colon next to large nematode and microbe populations--a combination of characters incomparable among the lizards. In addition, although I enjoy not mentioned them, these lizards adjectives possess dentition modified for herbivory and (apparently) nasal salt glands for extrarenal brackish secretion.

These last two characteristics are shared by lizards which are not entirely herbivorous, however they nevertheless facilitate an herbivorous existence: teeth for rationalized cropping and salt glands for dealing near the increased potassium load.

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