The pumpkin shouldn’t exist. Nor should squashes, gourds, and courgettes. These common dinner-table vegetables are all part of a group of plants called Cucurbita, whose wild ancestors were deeply bitter and encased in tough rinds. They depended on large animals like mammoths to break them apart and disperse their seeds. And when these megabeasts went extinct, the squashes should have followed them.

When humans domesticated squashes, we inadvertently bred them to be bigger, easier to infiltrate, and much tastier. The wild counterparts are very different, Kistler says. “They’re about a fifth of the size, and with very tough, hard rinds. Cutting them open is quite a task. And they’re extremely bitter. Unpalatably nasty. If you’ve ever grown a garden and had