Sex changes in Axolotls.

umbjork1 at cc.UManitoba.CA umbjork1 at cc.UManitoba.CA
Wed Mar 12 06:35:02 EST 1997


A few weeks ago I posted a question about an axoltol I had that was 
about three to five years old and appeared to be a normal female. Then 
all of the sudden I came in one to day this female had changed into a 
male (apparently) and had sucessfully spawned. I asked if anyone had ever 
seen such a thing before and if it was possible. I got many responses and 
the following is a summary of them.

Several people have contacted me with various ideas and proposals re the 
apparently sex changing axolotl. Two others have had similar situations 
come up where they had wondered if a sex change had occurred but neither 
was absolutely sure the animals had not been mixed up. A couple of people 
were adamant that there was simply no way the axoltol could change sex.

I had one interesting and quite plausible suggestion. Since we only used 
external characteristics to check the sex, the animal in question might 
have been a male who was delayed in going through the final steps of 
maturation. He merely appeared to be a large female but he was actually a 
male. Something (possibly changing homes since this animal came from another 
colony) pushed him to go through the final maturation stage and become 
sexually active with the typical large male cloaca. Since young axolotls 
appear to be all female and secondary sexual characteristics become 
visible at highly variable ages this seems to be quite plausible.

All three of the cases I have seen have been a female turning into a male 
and never the reverse. Also there are no breeding records of this 
particular animal or the other two I observed having previously spawned 
as a female. Without any firm literature on the topic, I think we must 
leave the possibility of a true sex change as something interesting to 
watch for but not in any way known to exist beyond anecdotal reports. A 
full documentation would require clear breeding records showing secessful 
spawning as a female and then as a male or the reverse. 

If anyone has ever had a male to female sex change among their axolotls I 
would really appreciate knowing. I would also really like to hear from 
anyone who has a well documented sex change.

My thnaks to the 27 people who took the time to respond. My apologies for 
not posting the answers sooner.

Natalie K Bjorklund
University Of Manitoba Colony
Winnipeg, Manitoba, Canada




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