Some of my boids constrict their prey, some don't. All of the snakes that need their prey dangled constrict it (except when my rainbows were fed in this way, they just swallowed it right from the tongs...lol). A few still constrict when taken off the ground as well, though many do not. Some of them will only constrict if there is any movement from the prey item, otherwise they just skip that step. One of my Jamaicans used to prefer to walk his prey around the cage a few times before he would gulp it down