Almost every list of popular pet names is one country's data presented as the world's. This catalogue counts eleven registers across three regions, and they do not agree — which is only visible if you keep the regions apart instead of summing them.
The sizes are wildly different, and that matters
The American registers hold 730,122 records, the Swiss 100,516 and the Australian 17,472. A straight sum would let the United States decide every ranking on this site, which is why popularity here is the average share a name holds across registers rather than its total count — a name common in Basel is not buried by one common in New York.
It is also why the site says plainly that five of eleven registers are North American and supply 86% of the records. Read any ordering as naming in those places rather than worldwide.
Where the lists diverge
The Swiss registers are German-speaking and their leaders show it. The Australian councils skew toward names the English-speaking world shares, which makes them look more like the American list than the Swiss one does. None of this is a claim about culture; it is what three sets of licence records contain.
What the data cannot support is a country-by-country ranking for anywhere else. There is no register here for the United Kingdom, Canada, Germany or France, so this site has nothing to say about them and will not guess.
Using it
If you are in one of the three, the regional block above is the closest thing to local data on this site. If you are not, the honest reading is that the catalogue tells you what is common in North America, with a Swiss and an Australian correction applied.
What are the most popular pet names in America?
Across the American registers: Lucky, Princess, Penny, Cooper and Oreo. Those five come from 730,122 records, the largest of the three regions counted here.
Do pet names differ by country?
In these registers, yes — the Swiss lists are visibly German-speaking and differ from the American ones. The site keeps the regions apart rather than summing them, because a straight total would let the largest register decide every ranking.
Which countries are covered?
The United States, Switzerland and Australia, through eleven public registers. There is no data here for the UK, Canada, Germany or France, and the site does not guess at them.
Every count on this site is a tally of real registrations: pet licences and shelter intakes published as open data by New York, Seattle, Austin, Montgomery County, Cambridge, Zurich, Basel and four Australian councils. Popularity here is the average share a name holds across those registers, so a name common in a small city is not buried by one common in a large one. Five of the eleven registers are North American and they supply 86% of the records, so read the ordering as naming in those places rather than worldwide. Browse the whole catalogue or read how the data is put together.