Crested Geckos make noises!

Early last night, in the dark, I heard noises from Spike and Mathilda's enclosure.  Almost like squeaking noises.  Odd!  I've thought I've heard similar noises, although for a shorter length of time and quieter, in the past but was never able to convince myself that it was actually them (or one of them).  I think that I now feel comfortable with going on record that it WAS them!  And, since the two are sharing an enclosure it may be some sort of vocalization between them, mating-wise.    I will keep my ears open!