How long does prey live?

When a bird swallows live prey (a heron swallowing a frog, say), does it die instantly? A Knott, Macclesfield

QAs far as we know, any prey swallowed live tends to suffocate within a couple of minutes, if the crushing action of the bill and throat muscles hasn’t already killed it. Whether the dying animal feels pain during this process is another matter. Whether invertebrates in particular feel pain is still contentious, but it’s probable that any pain felt by live prey is muted by shock upon being eaten.

A