Sexual Identification Of Caiman latirostris Hatchlings By Cloacal Inspection

HERNÁN CIOCAN; PAMELA ML LEIVA; MELINA S. SIMONCINI

South American Journal of Herpetology

Bio one

Año: 2019

1808-9798

Sexual identification of crocodilians is important in population studies. This information is also useful when preparing or proposing conservation and management plans, as well as monitoring these populations over time. In nature, it is possible to differentiate males and females of Caiman latirostris, by cloacal palpation or eversion of the penis in individuals larger than 75cm in total length; but smaller animals show a hardly differentiable cliteropenis. In hatchlings, sex determination methods involve surgical examinations, necropsies or analysis of cranial dimorphism, which are not applicable to field sampling conditions. We classified hatchlings of C. latirostris, observing the color and shape of their genitals. We were able to characterize penis as a milky white organ with a rounded shape at the tip and a purple hue at the end; while clitoris is shorter, whitish and with a pointed end. The procedure was tested on hatchlings from 3 nests, half of the eggs of each nest were incubated at a constant temperature of 31°C (producing females) and the other half at 33°C (producing males). To observe the sexual organs by cloacal inspection, we use an instrument that we made and whose function during palpation is like a finger applied in large animals to perform the eversion of the penis or clitoris outside. According to our observations, in the first days of life we correctly assigned the sex of 80% of the individuals. The number of correct identifications was slightly lower for females than for males. This technique would be a useful tool for field studies, for making it possible to estimate the sex of small caimans in situ.