Hemipenal Transillumination as a Sexing Technique in Varanids?

[Wiggles92]

I was reading an article (http://varanidae.org/Vol3_No1_Brown.pdf) on the aforementioned procedure, and I was wondering if anyone has tried it with any luck.

I just tried it on my two ~12" Nile monitors, and it appears that I have two females. I'm going to try again tomorrow except I will have someone else hold them so that I can take pictures in order to get a second opinion on the genders.

[jarich]

Ive heard a few people mention trying this but don't know what the success rate is for those outside of the article. It seems fairly straightforward, as long as the lizard is amenable to being put on its back like that.

[Wiggles92]

Ive heard a few people mention trying this but don't know what the success rate is for those outside of the article. It seems fairly straightforward, as long as the lizard is amenable to being put on its back like that.

Okay, cool.

I want to breed these monitors once they get older, and it's going to be way easier to do so if I make sure that I have both sexes in order hopefully alleviate future issues.

[red ink]

They use the technique mainly on odatrias here, from what I hear it works quite well. I don't know if it does for larger varanids like niles as the tail base might be too thick by the time the hemipenal bones appear and the light does'nt pass through effectively...

This might be a question for Crocdoc on here....

[mo9e64]

I don't think it's reliable or it would be a standard.sexing monitors is hard on younger animals,and different species are more difficult than others.As a beginner(assumption) with a goal of breeding,smaller species like Ackies are a better start.Niles have been bred alot-start with more juveniles for the odds of getting a male and female-but than you get in the intracies of social interaction,needing more cages if they aren't compatible.

[Gatorhunter1231]

I agree with the above. I wished it was as easy as putting some light on the subject because It would be easy for me to put together breeding groups. Most people wouldn't be able to tell hemipenis from hemiclitoris. I swore my croc was male after seeing it evert until it laid eggs. The hemiclitoris was well over an inch.

[Wiggles92]

I don't think it's reliable or it would be a standard.sexing monitors is hard on younger animals,and different species are more difficult than others.As a beginner(assumption) with a goal of breeding,smaller species like Ackies are a better start.Niles have been bred alot-start with more juveniles for the odds of getting a male and female-but than you get in the intracies of social interaction,needing more cages if they aren't compatible.

I'm new to the sexing & breeding aspect of keeping monitors, but I've worked with adults of various species in the past.

I'm going to pick up two more babies at the next reptile show if they have some for sale; that should give me a decent chance of getting both sexes.

[Gregg M]

I have sexed odatria this way and have never been wrong yet. It is very reliable in my opinion.

They use the technique mainly on odatrias here, from what I hear it works quite well. I don't know if it does for larger varanids like niles as the tail base might be too thick by the time the hemipenal bones appear and the light does'nt pass through effectively...

This might be a question for Crocdoc on here....

It is not the hemipenal bone that glows red when using this method. It is the vascular system.

[red ink]

I have sexed odatria this way and have never been wrong yet. It is very reliable in my opinion.



It is not the hemipenal bone that glows red when using this method. It is the vascular system.


Have you tried it on larger varanid species Gregg? I would be interested to see how it goes.

[Gregg M]

Have you tried it on larger varanid species Gregg? I would be interested to see how it goes.

I have not. The largest I would say is in savannahs. This has worked on hatchling animals in odatria so I cant see there being a problem doing it with larger species of varanid.

[mo9e64]

Greg, After thinking more about what i said about hemipenal transillumination,i realized i should have probably left it alone,i'll admit a comment without base.But is this something a beginner can do,to me and correct me if i am wrong it's something you learn through experience.What are your thoughts on beginners being interested in the sex of their monitors?

[infernalis]

.What are your thoughts on beginners being interested in the sex of their monitors?

Since we all know that you do spend quite a bit of time at Varanus, I would hope you know the answer to that already.

Knowing what you have at the time of sexual maturity is paramount if you do not want an egg bound (AKA Dead) female on your hands.

This is a subject that seldom gets touched on in "my monitor seems sick" threads.

We all know that females will hold in eggs for lack of suitable nesting.

[Gregg M]

Greg, After thinking more about what i said about hemipenal transillumination,i realized i should have probably left it alone,i'll admit a comment without base.But is this something a beginner can do,to me and correct me if i am wrong it's something you learn through experience.What are your thoughts on beginners being interested in the sex of their monitors?

Hey Mo,
It is something a beginner can easly do if they are shown once how to do it and exactly what to look for. As I said, it is a good way to check odatria and savs but I do not have experience sexing other varanids this way simply because I never had an interest in breeding the larger species.

I feel a beginner should know sex and it has nothing to do with breeding. Attempting to breed monitors should be left to those with a little more experience who has got their husbandry down pretty well in my opinion.

The reason I feel it is important is because males can be kept easier and can handle our husbandry mistakes a little better. With a male, you do not have to worry about things like nesting or worry about it becoming egg bound. Lets face it, no matter what information a beginner gets, they are still going to make mistakes. Even seasoned keepers make mistakes. No matter how experience we are, none of us have monitor husbandry completely dialed in.

[KORBIN5895]

Greg, After thinking more about what i said about hemipenal transillumination,i realized i should have probably left it alone,i'll admit a comment without base.But is this something a beginner can do,to me and correct me if i am wrong it's something you learn through experience.What are your thoughts on beginners being interested in the sex of their monitors?

Sure. If you are comfortable with them doing that to you.;)

[mo9e64]

I want the opinion from someone who after going from beginner to experienced can give us his view,perspective,insight.If we were all smart and had an inkling to breed monitors we'd start small-i imagine Greg has bred larger monitors and can give us insight on them being the first monitors we breed-pros and cons.

[Gatorhunter1231]

Greg, could you post or pm this process. I would be curious to give it a try on my tristis and ackies (adults and babies). If I see something then I may man up and try it on the crocs. Wattage, setup, etc. Im surprised I haven't seen John post it. I may have to pick your brains soon ;)

[infernalis]

Im surprised I haven't seen John post it. I may have to pick your brains soon ;)

I do often wish John would post more than just his pictures.

[Gatorhunter1231]

John is busy busy it seems and really only sticks to one forum that i know these days. Plus I think he is still running cybersalvator.com which I'd his website that is dedicated to monitors. Im Sure Greg could elaborate.

[Wiggles92]

Great stuff, everyone. I'll just stick the the "wait & see" plan since that seems like the best course of action for determining their gender.

Since we all know that you do spend quite a bit of time at Varanus, I would hope you know the answer to that already.

Knowing what you have at the time of sexual maturity is paramount if you do not want an egg bound (AKA Dead) female on your hands.

This is a subject that seldom gets touched on in "my monitor seems sick" threads.

We all know that females will hold in eggs for lack of suitable nesting.

Indeed, that's something that I hope to prevent. Hopefully having 24" or more of substrate that will hold a burrow will do the trick when they get to that size.

[Gatorhunter1231]

@ wiggles-gregs lighting technique may be worth a try and see if it pans out on a larger species. Has me curious.

[Wiggles92]

@ wiggles-gregs lighting technique may be worth a try and see if it pans out on a larger species. Has me curious.

Yes, it seems worth a try. I'm wondering if these Niles are old enough for it to work, though, as it takes a little bit for the area around the hemipenes to vascularize and that vascularization is what you have to look for.

[Pirarucu]

Digging up an old thread here, but I've been wondering. For those of you who have tried this, what size did the species in question need to be for this to work? Gregg, I see you said hatchling and I'm curious if you mean they can be sexed straight out of the egg using this technique, or if you need to wait a while. If so, how big/old did the monitors have to be before hemipenes (or lack of) were visible using this technique? I'm particularly interested in acanthurus, but I'd still be interested in hearing the results with other species.

[Pirarucu]

Nobody with an answer?

[Gregg M]

Gregg, I see you said hatchling and I'm curious if you mean they can be sexed straight out of the egg using this technique.

It can be done straight out of the egg.

[Pirarucu]

Thank you.

[simpleyork]

so how about the larger Varanids
like Savannahs and Ornates
and how big they need to be to be able to do so?

[Gregg M]

so how about the larger Varanids
like Savannahs and Ornates
and how big they need to be to be able to do so?

The smaller the animal, the easier it is.

Most of the time I do not need to use this technique to sex varanids. Most of the time it is quite easy to tell by head structure and tail bases. I use this technique on questionable animals.

[Gatorhunter1231]

My one month olds start being territorial and try to dominate each other which helps be get good ideas on sex. Plus my male ackies are brighter.

[crocdoc]

I must have missed this thread first time around.

TI don't know if it does for larger varanids like niles as the tail base might be too thick by the time the hemipenal bones appear and the light does'nt pass through effectively.

The idea behind this technique is that it can be done on young monitors, long before the hemipenes become ossified, as it is the blood vessels that are of interest rather than the ossifications.

I don't think it's reliable or it would be a standard. sexing monitors is hard on younger animals,and different species are more difficult than others.

It's still new, so it may well become a standard in a few years. However, it doesn't work with all species. I've tried it with lace monitors, as had a friend who also breeds a fair few, and we both found that there's an opaque black band at the base of the tail that obscures the detail so it's inconclusive with that species.

[simpleyork]

how soon can you tell by looking at the head and tail areas on savannahs , wondering what my two are