it means the appearance of the animal triggers a desire to hug or cuddle or pet it. evolutionary explanation is it’s a natural instinct resulting from reproductive success from a stronger desire to care for offspring.

with sexy men being called cute by woman I think it means they find them attractive in a way that’s not necessarily masculine. evolutionary explanation might be that they appear that they might produce offspring that are cute and therfore induce the desire to care for offspring in the parent.