Body size development of captive and free‐ranging Leopard tortoises (Geochelone pardalis)

Abstract

The growth and weight development of Leopard tortoise hatchings (Geochelone pardalis) kept at the Al Wabra Wildlife Preservation (AWWP), Qatar, was observed for more than four years, and compared to data in literature for free-ranging animals on body weight or carapace measurements. The results document a distinctively faster growth in the captive animals. Indications for the same phenomenon in other tortoise species (Galapagos giant tortoises, G. nigra; Spur-thighed tortoises, Testudo graeca; Desert tortoises, Gopherus agassizi) were found in the literature. The cause of the high growth rate most likely is the constant provision with highly digestible food of low fiber content. Increased growth rates are suspected to have negative consequences such as obesity, high mortality, gastrointestinal illnesses, renal diseases, "pyramiding," fibrous osteodystrophy or metabolic bone disease. The apparently widespread occurrence of high growth rates in intensively managed tortoises underlines how easily ectothermic animals can be oversupplemented with nutrients.

Growth patterns, sexual dimorphism, and maturation modeled in Pachypleurosauria from Middle Triassic of central Europe (Diapsida: Sauropterygia)

“…To estimate the age at which the individual reached sexual maturity from its growth curve (ASM), we assumed that the inflection point of the curve coincides with sexual maturation. Evidence for this concept exists in reptiles and amphibians (Kupfer et al, 2004;Lee and Werning, 2008;Reiss, 1989;Ritz et al, 2010). Under the GGM, ASM is seen at about 38 % of AL and under the LGM at 50 % of AL.…”

Intake, apparent digestibility, and digesta passage in leopard tortoises (Geochelone pardalis) fed a complete, extruded feed

“…This may be related to the effects of relatively higher growth rates observed in animals in captivity compared to those under free-ranging conditions [Ritz et al, 2009]. One captive male G. pardalis successfully bred at 4 years [Highfield, 1996].…”

“…Some of the literature suggests that causes of pyramiding, which itself has not been clearly defined, may include overfeeding, rapid growth rates, high protein diets, calcium or vitamin D deficiency, or an improper calcium:phosphorous ratio in the diet [Stearns, 1989;Ritz et al, 2009].…”

“…If growth was exponential during the study, this may explain why mean BW gain was higher per kg initial BW in period 2 compared to period 1. [Wilson, 1968;Ritz et al, 2009]. Data from the Cal Poly G.…”

“…Figure 6 Growth curve obtained from the literature including data points from captive (filled circles and triangles) and semicaptive (i.e., maintained in outdoor enclosures with access to native vegetation and occasionally supplemented with greens) (open circles) G. pardalis overlaid with data obtained from the Cal Poly G. pardalis colony, with lines to indicate the approximate duration of this study [Wilson, 1968;Ritz et al, 2009]. Σ(n•t) / Σn where n is the amount of marker recovered, and t is the time (h) between administration of the marker dose and the end of collection [Udén, 1978;Holleman and White, 1987;Stevens and Hume, 1995] sADF Acid detergent fiber determined sequentially after NDF analysis, composed of cellulose, lignin, cutin, and ash SV Shell volume, calculated as SV, cm 3 = (π · MSCL · CH · PW)/6 [Loehr et al, 2007] T 50 Time (h) to cumulative recovery of 50% of an indigestible marker dose in feces post dosing [Barboza, 1995] T MAX Time (h) to recovery of the maximum marker concentration in a single fecal sample post dosing [Barboza, 1995] TT 1 Transit time, or time (h) to first appearance of an indigestible marker in feces post dosing [Holleman and White, 1987;Stevens and Hume, 1995] V N Indigestible fill, an estimate of the volume of the digestive tract for undigested material, based on the product of an estimate of the flow rate (total fecal output per collection) total passage time (R GIT ) observed, calculated as V N , g = F · R GIT , where F is the total fecal output [Holleman and White, 1987;Barboza, 1995] …”