There is a lot of variation in both species. Some Corns get really big like 5 feet, while others rarely get over 3 1/2 feet. Milks do have the biggest variation, as some remain under 3 feet, and some get to 6 feet or better. I like them both. Oh, not all milks are super jumpy. Some tend to calm down much faster than others. Sinaloans, and Nelsons are fairly calm, after a short time of handling, and they remain calm. Some Corns can also be pure evil, lol. Yet most are very mild tempered, and tame.