Took an audio production class in the radio-TV department of the local community college.
The prof. tested the whole class by playing tones of frequencies- starting from the top (20 khz) and going down. You raised your hand when he came down to a frequency you could hear. Most in the class raised their hands before I did as he went down into the upper teen kilohertzes ( most hands were up by 17 but I had to go to some point slightly lower). But I was one of the older people in the class . So I guess that was to be expected. But even as a child I dont remember being able to hear a dog whistle.