YOU MIGHT TRY CONTACTING ANY OF SEVERAL COMMERCIAL CROCODILE FARMS IN AUSTRALIA VIA A GOOGLE SEARCH. ONE IN DARWIN AREA COMES TO MIND. I'VE SEEN VIDEO OF THEM CHECKING HATCHLINGS... CAN'T REMEMBER IF IT WAS WITH A OTOSCOPE OR MERE TONGUE DEPRESSOR-LIKE TOOL. PRINCIPALLY LOOKING FOR A PROTRUDING STRUCTURE POINTING TOWARDS THE CLOACA THAT INDICATES A MALE. WITH LARGER ANIMALS IT IS ACCOPLISHED BY A SIMPLE INDEX FINGER INSERTION!