Journal of Veterinary and Applied Sciences

Abstract
Radiographic evaluation remains a primary diagnostic tool in reptile medicine; however, interpretation of reptilian radiographs is often limited by the lack of species-specific anatomical and physiological reference data. This study provides a descriptive assessment of skeletal radiographic anatomy, gastrointestinal transit dynamics and sedation response of the Graceful chameleon (Chamaeleo gracilis) under controlled environmental conditions. Four clinically healthy adult chameleons were examined following a two-week acclimatization period. Radiographic imaging was performed in lateral and dorsoventral projections, and gastrointestinal transit time was evaluated using orally administered barium sulfate contrast. Morphometric measurements were obtained from digital radiographs and subjected to descriptive statistics. Sedation was achieved using ketamine (40 mg/kg, intra-muscular) and xylazine (5 mg/kg, intramuscular), with physiological parameters monitored throughout. Radiographs demonstrated well-defined skeletal structures with prominent caudal vertebral elongation. Morphometric analysis revealed a mean body length of 11.13 ± 0.26 cm, head length of 3.00 ± 0.00 cm and tail length of 27.50 ± 0.41 cm. The radius: humerus ratio was 0.86, while the tibia: femur ratio was 1.22, and the tail: body ratio was 2.47, which are consistent with arboreal specialization. Gastrointestinal transit was characterized by rapid oesophageal passage (2.00 ± 0.00 minutes) and gastric filling time (28.0 ± 3.65 minutes), brief gastric emptying (28.0 ± 3.65 minutes) and prolonged small intestine (474.5 ± 9.60 minutes) and colon (594.0 ± 20.8 minutes) transit times, with total gastrointestinal transit time averaging 1103.5 ± 27.7 minutes (18.4 hours). The small intestine and colon accounted for the majority of transit duration (43% and 54%, respectively). Sedation with ketamine and xylazine provided effective immobilization without observable complications. These findings serve as preliminary reference values for radiographic anatomy, gastrointestinal transit time and ketamine-xylazine induced sedation in C. gracilis. The data generated will facilitate interpretation of diagnostic images of the chameleon.

Keywords: Chamaeleo gracilis; Radiographic anatomy; Gastrointestinal transit time; Contrast radiography; Morphometry; Sedation response.

How to cite this article:
Fabiyi BO, Alabi FT and Olatunji-Akioye AO (2026). Preliminary evaluation of the radiographic anatomy, gastrointestinal transit dynamics and sedation response of the Graceful chameleon (Chamaeleo gracilis). Journal of Veterinary and Applied Sciences, 16(2): 1618 – 1629.

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