Use of ultrasonography and contrast radiography for snake gender determination.

The purpose of this paper is to characterize the sonographic and radiographic features of hemipenes in male snakes and to use these features for gender determination. The sonographic and radiographic examination of 17 male and 10 female snakes, whose gender was determined previously by probing, were evaluated by one examiner who was unaware of the gender. Sonographically, hemipenes appeared funnel shaped with an echogenic thin wall and hypo to anechoic contents. Radiographically, hemipenes filled by positive contrast medium appeared as funnel-shaped radiopacities pointing caudally. Snake gender was correctly determined in all snakes using sonography (accuracy = 100%). Radiographic accuracy was 81.4%. Interpretation of radiographic examinations was limited by poor distribution of the contrast medium within the hemipenes.