1955-1959: Ice Capades Pluto The first Pluto that roamed Disneyland was borrowed from the Ice Capades and required two performers.
1960 - 1977 Pluto gets a redesign., He now walks on two legs, has no collar and had a closed mouth. There were a few different variants of this Pluto
1973 This Pluto (pictured here with Goofy and Donald Duck), seen in Disney on Parade in 1973, had larger eyes.
1977 Another variant of this Pluto, greeting guests circa 1977, has thick black eyebrows.
1978 - 1993 This Pluto was introduced in 1978 and is very similar to Modern Pluto but with a few differences. Most apparently are his pupils, which are much larger than previously. It would appear that this Pluto only appeared at Disneyland, with a few appearances at Tokyo Disneyland. By 1990, Modern Pluto had been fully introduced at Disneyland and this Pluto made his final appearance in 1993.
1978 - Present: Modern Pluto. The current Pluto costume, first seen in the late 70's, looks more like his cartoon counterpart. He received a re-sculpted head and new body. He has a happier, friendlier appearance, with his mouth open and his tongue sticking out. He also wears an orange collar with a name tag. Around 2005, Pluto was updated to have a shorter tongue.
Starting from Mickey's Most Merriest Celebration which debuted in 2016, Pluto gets an articulated head with a pink cartoon tongue instead of his regular plastic red one and his whiskers are thinner and shorter. His mask almost looks like the one in the 1960's.