Twelve of the Oreodonts missed the Ark!
Oreodont sounds like a good name for an oreo-cookie flavoured donut. Oreodonts are actually a group of extinct pig-like animals, which is kind of fitting because oreo-flavoured donuts sound like food fit for a pig. However, oreodonts would get sick from eating donuts, because they did not have a digestive system like a pig. They were ruminants, like cows and goats, which means that they ate difficult to digest vegetation, swallowed it to ferment it in their first stomach, and then regurgitated it to chew it again. This process is known as chewing the cud, and is best known from its Biblical significance:
“And the swine, because it divideth the hoof, yet cheweth not the cud, it is unclean unto you: ye shall not eat of their flesh, nor touch their dead carcase.” (Deuteronomy 14:8)
That verse makes it pretty clear that a pig that did chew it’s cud would be clean. Thus the pig-like oreodonts, which had four-toed hooves, would presumably have been clean.
And yet, on the Ark Encounter list, Merycoidodontidae, which is the scientific name for the oreodont family is shown under the unclean kinds! This means that they only accounted for two individuals instead of 14. These were roughly pig-sized animals, and the pen on the Ark Encounter for pigs is approximately 7.5m2 for two individuals. This implies that the missing 12 animals would require about 45m2 of extra space.
In general, the clean mammals are generally fairly large animals, and the requirement for 14 individuals multiplies that substantially. Therefore, missing clean animals significantly affect Ark capacity.
Featured image by Apokryltaros at English Wikipedia, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=8942186