I found this info from another site which showed a way to sex the Tegu's from the lumps (spurs) near the Tegu's Vent/tail area. I asked a question there that I have not received a response back yet.
1)HOW old do the Tegu's need to be to be sexed this way?
2)Can a Argentenian and Columbian Tegu be bred together?
I was told by a reptime shop that they could be. Anyone here have this info? Thanks in advance..
http://thetegu.com/modules.php?name=coppermine&file=displayimage&album=14&pos=3

