In Genesis, Noah brought two of each unclean animal onto the Ark.
Genesis 7:2 instructs Noah to take one male and one female of every kind of unclean animal. This produces the familiar summary of two animals per unclean kind. The paired male-and-female wording also supports the account’s emphasis on preserving animal life for the world after the Flood.
The same passage gives a different number for clean animals, which is why the Ark’s animal count is sometimes described inconsistently. Genesis 7:2 says seven pairs of clean animals in many translations, while Genesis 7:3 says seven pairs of birds. Some translations render the Hebrew as seven individual clean animals, creating a translation difference.
The unclean-animal figure is less disputed because the instruction plainly describes one male and one female. The text does not provide a modern species inventory, so “two” applies to each stated animal kind rather than to a counted list of contemporary species.