Pumpkins nearly went extinct 10,000 years ago when the giant ice-age animals that dispersed their seeds died out.

Wild squash and pumpkins belong to the genus Cucurbita and were once highly toxic to most mammals due to compounds called cucurbitacins. These chemicals are extremely bitter and can cause serious illness or death in small and medium-sized animals. However, megafauna like woolly mammoths and giant ground sloths had enough body mass to tolerate the toxins and possessed flat teeth capable of grinding through tough rinds.Research published in the Proceedings of the National Academy of Sciences (PNAS) in 2015 demonstrates that these giants were the primary seed dispersers for wild gourds. When megafauna went extinct approximately 10,000 to 12,000 years ago at the end of the Pleistocene epoch, the natural distribution system for pumpkins collapsed. The plants became confined to small ecological niches where extinction risk was high.Archaeological evidence reveals that early humans in the Americas began domesticating these plants around 10,000 years ago. By selecting seeds from naturally less bitter plants, humans gradually reduced toxic cucurbitacin levels over successive generations. This selective breeding transformed a toxic weed into a nutritious, storable food source. The pumpkins we carve today and use in pies are direct descendants of the plants these early farmers rescued from extinction.