Scientists finally solved the grass-eating mystery using microscopic evidence.

Cat owners have long puzzled over their pets’ habit of munching grass only to vomit it back up minutes later. This seemingly pointless behavior has baffled scientists for decades, spawning theories about everything from parasite removal to nutritional deficiencies. The mystery persisted because no one had looked closely enough at what actually happens when grass meets hairball.
Recent research has finally cracked this feline code using an unconventional approach that involved coating cat hairballs in gold. The findings reveal that cats have essentially discovered a natural plumbing tool, using grass’s microscopic features to manage one of grooming’s messiest side effects.