Anna is one of the most stable names in the Western world — it has barely varied in usage or spelling for a thousand years. On a pet, it reads as simple, clean, and completely unpretentious. Owners who name their dogs Anna are usually not making a statement about anything beyond the fact that they like a name that doesn't require explanation.
The Frozen Effect
Disney's Frozen (2013) gave Anna a pop-culture moment that was large enough to register in human naming data. For pet names, the effect is subtler but probably real — owners who grew up with the film or who have children who love it may carry the association warmly. Anna is a good name regardless of the reference, but the Frozen connection gives it a contemporary warmth it might not have had in 2008.
Human-Pet Name Crossover
Anna is unambiguously a human name first — the human Anna page carries centuries of documented use across Hebrew, Greek, Latin, and most European language traditions. That means naming a pet Anna reads as genuinely affectionate rather than cutesy, in the same way that naming a dog Henry or Margaret signals a certain kind of owner. Golden Retrievers and Border Collies turn up often in this name's registry data.
Counter-Read
Anna's simplicity is its strength and its limitation. If you want a name with more personality or cultural edge, compare Anya or Nadia for similar origins with a different energy.