I haven’t kept Jackson’s in a long time so I don’t know if the red gular is indicative of sex or not.
That said, if you look closely (a cheap magnifying glass helps) the males will have 3 small horn buds on their heads; one each above their eyes and one on their snout. Females would be lacking these bumps, have one on their snout only or all three would be rudimentary.
You didn't indicate whether those two photos are of the same animal but based on cheek patterns I'm assuming they are different. If so, I'd likely say you have two males based on the significant horn development already at this young age. Some female xantholophus do have three horns but the horns are quite small as adults and would doubt they would be that big at a few weeks of age.
Really! Two males. Sweet. Sorry but ya they are two different chams but they have that red on the throat but I guess males must have that when really young also. Thanks for the info i really appreciate it!
I have 21 baby xantholophus that are just over a week old. All of them have the same horn buds. The only reliable way to sex them when they are this young is by the tail base. After about a month you'll start seeing difference's in horn growth.
If you can get some pictures of them walking on a branch with tail extended we can give you a better idea of what you have.
there is also another way - I was taught to look at the angle of the nose- so far, it has been accurate for me - the girls will have a more up/down snout - the boys will have a little V shape from a profile view - the one on the right is a girl , the on the left , the boy - my baby girls seem to always have horn buds about the same size as my little boys, so I use this way but I love to see all the ways you can check