pronghorn (Antilocapra americana). They were so cute. Pronghorn mate in the fall, and every spring we see little ones around (if we're lucky enough to be in the right place at the right time).
Within a few days of being born, pronghorn can outrun humans. They eventually get up to 53 mph, the second fastest land mammal in the world, after the cheetah. Fortunately for them, no cheetahs live around here. Pronghorns do have to slow down when they get to a fence, as they don't jump over them but rather crawl under them. It's a strange sight, but they seem to do it pretty well.
When the young pronghorn caught up to their mom, it was easier to see their size. Even though we had stopped alongside the road and were watching them, they didn't seem very alarmed.
Eventually they ran off. I bet the next time we see them the young will look appreciably larger.