Dug is the lovable, distracted golden retriever in Pixar's Up (2009) — equipped with a collar that translates his thoughts into speech, instantly producing one of the most beloved dog characters in animated film history. "SQUIRREL!" is the defining moment. Every dog named Dug is being acknowledged, honestly and lovingly, as an animal who would absolutely do the same thing.
The Up Legacy
Up's Dug captured something true about dog cognition — the enormous, genuine love combined with spectacular distractibility — and the name has been a consistent choice for golden retrievers and other affectionate, easily-excited breeds since 2009. Golden retrievers are the canonical Dug breed: the same coloring, the same bounding enthusiasm, the same capacity for complete devotion interrupted by sudden squirrel awareness. The spelling Dug rather than Doug is load-bearing: it's the character's name exactly.
The Name's Brevity as a Feature
Dug is a single syllable, functionally perfect for a recall name. It's impossible to abbreviate further and it calls cleanly in any environment. The contrast between the name's brevity and the character's enormous personality is part of what makes it work. See also Russell for the human boy companion from the same film.
The Counter-Reading
Dug will prompt the SQUIRREL comment from everyone who recognizes the reference, for the entire animal's life. This is either the point or the price, depending on the owner's patience for the bit. The human name Doug, the standard spelling, is a mid-century classic; the Dug spelling is entirely owned by the Pixar character.