How many clean animals were on the ark?
The Bible says either seven or fourteen (it’s ambiguous) of each kind of clean animal was aboard. It defines clean animals essentially as ruminants, a suborder which includes about 69 recent genera, 192 recent species [Wilson & Reeder, 1993], and probably a comparable number of extinct genera and species. That is a small percentage of the total number of species, but ruminants are among the largest mammals, so their bulk is significant.