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How To Sex A Crocodile
The physical appearance of crocodilians is very much the same for both males and females. As the animals mature the male may take on a beefier macho look and have a broader snout but if you don't know its sex in the first place or only have two or three animals of various ages then it will be only supposition. You may just have a fat female.
If there is an intention to breed the animals the sexing them is a necessity. It may be possible to do this without handling the animals at all, perhaps by collection and chemical analysis of scats or by close observation of behaviour. To be absolutely sure though the only way is through physical handling.
In the normal run of day to day routine it should not be necessary to even enter an enclosure with a crocodilian. The only time it should be considered is when an animal is ill, to determine its sex or perhaps check a nest or malfunctioning appliance. Handling involves team work. Team work needs planning. Risk assessments are critical.
The Crocodilians are split up into three groups, Alligatoridae, Crocodylidae and Gavialidae. These combined are made up or 23 different species. Although there are some quite obvious differences between these species when it comes down to sexing they are all very much the same.
The Sexing Procedure
I am only too happy to admit it. I have not had to sex many crocodiles. Perhaps ten, a dozen at most but I daresay that is many more than most people. I don't consider myself an expert on the subject and the task has been one of a multitude of activities I have had to perform during forty years working in zoos.
The crocodilians tend to be generally hardy and inoffensive. It may well be that the only time in a crocodiles life that it will be handled is when its sex is determined.
Crocodiles are a lot stronger than they look and so it is important that you have enough people in your sexing team in the beginning. They should be confident and fully aware of the role that they are going to play. It should be talked through before any action takes place. The size of the animal will determine the best method to use..
I have never used a lasso around the jaws as some do. With my team ready I approach the crocodilian from behind and throw a damp hemp sack over the head covering the eyes and jaws. At exactly the same time I jump astride the back of the animal holding the head down and jaws closed. My team will have immediately joined me with those appointed sitting on or preventing the beast from struggling. I have little doubt that with a crocodile of more than 8' that some ropework would be essential.
Actually once the head is covered the crocodile is surprisingly quiet. They do not fight much. The jaws of a crocodilian are extremely difficult to pull open (I know this from force feeding) but very easy to keep closed. In fact it is possible to hold the jaws of a medium sized crocodile closed with one hand. During the sexing procedure however we wrap some electrical tape around the jaws and keep them closed.
With the tape in place the team gently roll the crocodile onto its back. Surprisingly once the animal is inverted in such a way it becomes very relaxed, almost comatose. The team however remain in place holding the animal gently in case of struggle.
When the animal is on its back it is sometimes possible to tell immediately if it is a male or a female. The genitalia of crocodilians is internal and the cloaca/vent of both males and females appears the same. There are subtle differences however. The cloaca/vent of the male is larger, wider and tends to protrude outwards more. That for the female is the opposite.
Having got so far it is advisable to make absolutely certain and the only way to do that is through an internal examination. Using a clean lubricated finger you probe inside of the cloaca/vent. If the animal is a male it will be immediately obvious because you will feel the soft cartilaginous penis. In a 6' long animal it will normally be about the length of your finger or thereabouts. The clitoris of the female is very much smaller and softer too. As I mentioned at the beginning of the article the difference becomes only too obvious once you have sexed both a male and a female crocodilian. Mistakes can be made especially with younger or smaller animals.
Releasing the Crocodile
Releasing the crocodile is a reversal of the catch up procedure. The animal is slowly rolled back onto its front. the tape closing the mouth is cut free. The team step away and behind the animal but remain ready. Myself at the head end then steps back and behind the animal last of all.
The hemp sack covering the animals head is then removed gently with a stick. In most instances the animal will just lie there as if nothing had happened at all and continue on with their daydreaming.