thank you both for the quick replies. will measure them and get back to you. in the meantime, the younger (Scooby) is much larger (probably 1/2 inch) than the oldest (Daisy) and has a much more voracious appetite. if it matters, Scooby has turned a bright light green a few times. how saggy does the skin have to be? does anyone have a side by side photo of male/female throats for me to compare?