They are a sex ratio. Say you see 2.3 That means there are 2 males and 3 females. If you have 2.3.1 That means 2 male 3 females and 1 unsexed. See, the males are on the left side of the period and females are on the right. If you have an unsexed animal it would go to the right of the females, separated by another added period. Hope this made sense, thanks.
"A monk was traveling and came to a fork in the road. He stopped, looked at it and decided to leave it there for someone else to ponder, someone who may need it, for his own spoon was quite sufficient."