These doggy tones are so sophisticated and uber-cool that your decidedly uncool human ears wont even pick them up. It just helps your doggy pal to enhance his status in front of the other pooches.
Tokyo-based mobile content provider Dwango has announced a range of ringtones that are audible only to dogs. Inu ni shika kikoenai chakushinon ringtones only dogs can hear will be downloadable to DoCoMo phones.
As to the, No seriously, why question, we have no answer except that it happens only in Japan.