Oh I just meant domestic pets appeal to the same parts of the human brain that human infants do, in part because humans have bred domestic pets to retain infantile traits into adulthood. For example, an adult dog retains most of the personality traits of a baby wolf, whereas an adult wolf does not.

This is somewhat analogous to your explanation of dolphins acting altruistically toward humans because we resemble their young when struggling in the water.

In the same way, it would be very hard for most of us to ignore a lost crying puppy wandering down the street.