I think the passenger pigeon just got surprised by a new threat to which it couldn't adapt fast enough. It happens.
Their breeding strategy required massive colonies to fill the local predators' bellies and still have survivors. They didn't really count on a predator that would take entire colonies. Nets, alcohol soaked grain, fire arms, explosives, coupled with a huge national demand coupled with a vast transportation network were nothing like foxes, snakes, and birds of prey.
Musk oxen have the same problem. "Back into a mass protecting the young with your heads facing outward" doesn't work well against rifles. They don't have much of a plan B. Being dark on a barren, white landscape much of the year also sucks.
Many of the pelagic fish also fall into this category. They aren't built for a predator that will scoop up an entire 4000kg school of fish in one swipe.
Their breeding strategy required massive colonies to fill the local predators' bellies and still have survivors. They didn't really count on a predator that would take entire colonies. Nets, alcohol soaked grain, fire arms, explosives, coupled with a huge national demand coupled with a vast transportation network were nothing like foxes, snakes, and birds of prey.
Musk oxen have the same problem. "Back into a mass protecting the young with your heads facing outward" doesn't work well against rifles. They don't have much of a plan B. Being dark on a barren, white landscape much of the year also sucks.
Many of the pelagic fish also fall into this category. They aren't built for a predator that will scoop up an entire 4000kg school of fish in one swipe.