I think this answers the question. As mentioned, human babies are totally defenseless against anything from life-threatening predators to a swarm of mosquitoes. Any discomfort, real or perceived by the infant mind will cause it to start bleating. And also as mentioned, we are generally tuned to the cries of a baby, either out of pity or irritation, and the parent will always go see what the problem is (out of a desire to help or annoyance). Either way, the baby gets attention, which is really all they are geared to do at first.
I’ve heard that elephants exhibit similar behaviors: In the rare event that a lioness takes an elephant calf, the adult elephants will track down and kill the lioness and all of her cubs.
Though baby elephants aren’t anywhere near as helpless as baby humans: Not much short of a lion would even have a chance at killing a baby elephant.
I worked on a pig farm for a short time; the piglets squeal almost incessantly and just as loud an sharp as my own kids did. Also, just being heard doesn’t = death by predator. Robin parents give away their own presence, and hence the fact that they have a nest with young or eggs as a rule when you wander too close.
Yet my cat, and excellent stalker/hunter, doesn’t seem smart enough to clue in on that pattern.