Good catch on the sevens, I missed it and that was my post.
But I don't think the "sevens" can mean "seven pairs" any more than the "twos" mean "two pairs." If the chimps are "clean animals," then there were seven of them in that story, not fourteen.
Look at the phrasing in verse 2. " ... by sevens, the male and his female". Obviously taking about couples (mated pairs) here. If there were only seven individuals it would be impossible to have the male and his female because you'd always have an odd male or female.
Note also that the word used to define the quantity of clean beasts is plural (sevens) while the word used to define the quantity of unclean beast is singular (two)
GSA(P)