Calabacita squash is commonly nicknamed “Mexican zucchini” due to a few similarities with what we commonly call zucchini squash in the United States. However, the two squashes do come from different plants.  The squash commonly known as calabacita is the tatume squash. It has a similar size, shape, and color when compared to zucchini, which is where it got its nickname. Generally speaking though, the flesh of a calabacita squash is sweeter and whiter than zucchini flesh, and its seeds are far smaller.