Reptile & Amphibian Forums

Okay~ I'm reading "Giant Lizards" by "Robert George Sprackland" copyright 1992~ and on Page 55 I stumble across this little tid-bit:

"If an animal satisfies you as to health, check the sex of the animal. If your diagnosis differs from the dealer's, ask him how he arrived at his choice. Some lizards, such as iguanas, are said to be able to change sex, and Tom Huff of Ontario's Reptile Breeding Foundation has recently documented sex change from male to female in African plated lizards (Gerrhosaurus)."

This is amazing!~ But THEN it goes on~

"This is a trait shared with many birds and fishes (and even, apparently, humans—in a remote Central American village all the children are born female, but about half the population turns male with the onset of puberty at about age 12, according a recent study published by Stanford University Alumni Press).

NO WAY! This is an older book (14 years) This was a typo or something right?!?!
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Cheryl Marchek
AKA JM
Check out my website at:
The Red Dragons Den

They are talking about it in the broad sense. While actually what I have seen is individuals that appear as niether/either sex. What I mean by that is they show no signs of being either male or female. Most call these he/shes in the monitor world.

They are what they are, we just cannot tell what they are. It is not that they are one then change to another. They are simply late bloomers for one reason or another.

I have never had a confirmed male start to lay egg's, just as I have not had a egg laying female change to a confirmed father.
If this has been documented then yes that would be interesting.

While some vertebrates (various fishes in particular) can change sex, no reptiles, birds or mammals have been shown to do so once they have differentiated into males or females. The sex of some reptiles is determined by incubation temperature, but once they're set, they're set. These are species that do not have differentiable sex chromosomes. All herps that have identifiable sex chromosomes (XY, or ZW if the female has the mix-and-match set) show genetic, hard-wired sex determination.

Monitors have a ZW system. Watch out when you read Sprackland, it's often an "or something" with him.

Hi JM,

I know Robert and I knew Tom Huff as well; I miss Tom, as he was a terrific fellow. I can understand about the reptiles and birds changing sex, but the hominds in South America! HAHAHAHA.

I have pasted that section you wrote, and sent it to Robert for his comments - and look forward to learn/hear what he writes back to me about it, and asked him to give me the citation to follow up! Maybe that explains why so many of the men across the bay from me in San Francisco Bay are so feminine-like?? hahahaha.
Will get back to you soon on this I hope.

Cheers JM,
mbayless