Surprise with sex ratio n_n

[Azhael]

So lately some of my marmoratus had been developing a very small crest. At first i didn´t give any importance to it since i thought it was nothing relevant. But today when i was feeding them i noticed that the four of them that had been developing the tiny crest now had a slightly bigger one. Also the crest is developing the characteristical "banded" appearance, and a closer look showed that their cloacas are now bigger and rounder, with a clear and big difference to the other two newts. So i´m asuming they are definitely males, which means i have at least 4 males in a group of 6 xDDD One of them though is the kinked one, who has a surprisingly nice apettite and is doing fine. The damages on the spine are evident, and the four toed foot it has still has a weird way of moving....but hey it´s alive and growing. I remember Ian when you gave me 6 just in case, to improve the chances of getting some male hehehe...very odd sex ratio in my opinion...

 

[Kaysie]

Well, that's not so far off. Out of 6, the 'average' would be 3 males to 3 females, so having 4 males isn't a big difference.

Males look nicer during most of the year anyway

 

[Jennewt]

Yes, that ratio is very normal. You were lucky, actually. T. marmoratus are infamous for uneven sex ratios, because the juveniles have a M/F color difference. If some people get the bright-green offspring and some people get the drab offspring, they are all likely to find themselves with 100% single-sex. I believe that it's the females that are more brightly-colored as juveniles. That reminds me, I think this should be added to the caresheet on CC...

 

[coendeurloo]

Indeed Jen, all the experts seem to know this and I found out this was the case via this forum in a thread about my juveniles.

 

[Azhael]

oh....well...i thought there was a higher percentage of females in captive bred animals....I mean, it should be 50/50 but i´ve been told by several people that they always got more females...
Ok i guess i was wrong...sorry.
btw...i read about the colour differences between sexes somewhere....but mine where all the same, except for one that was darker and one that was a lot lighter....both, the darker and the lighter ones are males. I´m very happy actually..cause the lightest prettiest one is going to be a killer male.

 

[Jennewt]

I have heard various reports about odd sex ratios in marmoratus (even in cases where there was no selection for colors). I don't think there is a consistent over-abundance of females, but maybe I just haven't heard about it

 

[eldaldo]

My T. karelinii Juvies are getting to the point where I don't think it is right to call them juvies anymore and out of 7 I only have 1 male. I wonder how much of weird sex ratios is just due to random chance or if there are environmental factors that contribute.

 

[ButtercupSaiyan]

This is just a random fact, but the gender of crocodiles is determined by temperature ... perhaps vaguely related. The only other thing I can think of to account for uneven gender ratios would be stress by the environment in captivity that results in lower success for the male gender at the larval stage; is there a size difference as well as a color difference in this species?