In Genesis, Noah brought one pair of each unclean animal into the Ark.
Genesis 7 distinguishes between clean and unclean animals. Noah is told to take seven pairs of clean animals, while the instruction for unclean animals is one male and one female—one pair. The distinction appears immediately before the Flood begins and is part of the narrative’s animal-counting details.
Readers often remember only that animals entered in pairs, or they apply the seven-pair number to every species. That creates a common mix-up. The text gives different numbers for clean and unclean animals, and translations may phrase the clean-animal instruction as “seven pairs” or “seven of each.”
The passage does not provide a modern zoological classification. “Clean” and “unclean” are categories within the biblical ritual framework, and Genesis does not list every species included in either category.