Mickey's faithful four legged friend Pluto has been by his masters side since....... 1930 ( so he is over 81 years old..... which means in dog years he is knocking on 567 years ! )
Original known as ROVER he was soon renamed PLUTO the PUP. ( but you can call him plain old PLUTO these days) . Originally just a supporting character, he would later go on to star in many of his own cartoon film adventures.
Here we have Buddy doing his best to impersonation of the Disney Dog himself PLUTO