How to sex Giant otter Pteronura brasiliensis (Gmelin, 1788) cubs

Abstract

• Sexing living neonate mammals may be difficult as external genitalia may be poorly developed and time may be limited for a detailed examination. Four neonate cubs of the Giant otter Pteronura brasiliensis were examined in order to determine a method to distinguish between the sexes. The distance between anal and genital openings in ♂ cubs is about eight times greater than that in ♀ cubs, providing a simple method for determining sex.