Veileds are sexually mature at 4-6 months. What kills them all off is the dry season. The leaves fall off the trees, the food disappears, and water becomes scarce. The complete lifecycle, as I understand it, is:
Babiea are born right at the end of the dry season, which lasted approx six months. As the wet season gets into full swing, they grow like mad, consuming anything and everything. (We see vestiges of this behaviour in captivity, as veileds are by far the fastest growing and most likely to become obese of many if not all of the species commonly kept in captivity). By 4 -5 months, they are sexually mature and they mate. After an approximately one month of gestation, the female lays her eggs just before the onslaught of the dry season—which typically sees a 90% decline in the population. The eggs incubate for six months, and emerge with the start of the wet season.
Again, I am not a scientist, nor have I witnessed this first hand. And I should’ve been more tentative in my earlier post, given that my sole source for this information was a discussion between Petr Necas and Bill Strand on the chameleon breeder podcast. One source does not a fact make. But given the source and the intuitive nature of the explanation, my intuitions go in that direction. But neither does intuition = fact. So, while I’m inclined to accept this account, I stand equally ready to revise my position in the wake of solid contravening evidence.