AEO INDEX OCTOBER 2026 USA: Purina leads AI’s pet product recommendations, yet ChatGPT, Gemini and Google each pick a different best dog food brand
On the simplest pet question there is, the three engines split three ways. Outside the food bowl, specialists take over.
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Purina comes first in more AI pet product answers than any other brand, at the top of 9 of 30 answers from ChatGPT, Gemini and Google AI Overviews in Answer Engine Daily’s October 2026 AEO Index. It is also the most visible brand on all three engines, named in 73% of answers.
The most basic question in the set did not produce a winner, though. Asked for the best dog food brands, ChatGPT ranked Hill’s Science Diet first, Gemini picked Purina and Google AI Overviews chose Royal Canin. All three brands finished on the same score.
Answers were collected on 21 October 2026 from one U.S. location, with analysis powered by markaeo.com. Every question and engine is in the full October 2026 report.
How far ahead is Purina?
Each brand gets an AI Rank Score from 0 to 100, which rewards being named near the top of an answer; first place everywhere would score 100. Purina scored 52.0, well clear of Hill’s Science Diet at 37.7 and Royal Canin at 33.7.
Purina won cat food with a perfect 100, puppy food with 87 and wet cat food with 93, and it shared dog food. Five of its nine first places came from Gemini. The lead carries over to the pages the engines cite. Of the 103 we could read, Purina was the most-mentioned brand on 34. Next was Nutramax, on 6.
Hill’s Science Diet is named in 53% of answers and ranked first in 2, both by ChatGPT. Royal Canin is named in half and also has two first places, both from AI Overviews.
Why is dog food a three-way tie?
Each engine put a different one of the same three brands first and kept the other two in its top three. So Hill’s Science Diet, Purina and Royal Canin each scored 80. No other brand came close; Orijen was fourth at 27.
Senior dog food split three ways too. Hill’s Science Diet won at 87, but only ChatGPT ranked it first. Gemini chose Purina, and AI Overviews picked Open Farm, a brand that appears in none of ChatGPT’s answers in this category.
Across all ten questions the engines agreed on the top brand twice, Purina for cat food and Zuke’s for dog treats. Eight different brands won the ten questions, and away from the main food questions the winners are mostly specialists:
- Dog treats: Zuke’s, 100, with all three engines agreeing. Purina was not named on this question.
- Flea and tick: Simparica, 67. ChatGPT ranked Frontline first instead.
- Grain-free dog food: Orijen, 67, ahead of Wellness at 60.
- Pet supplements: Nutramax, 87, even though ChatGPT and AI Overviews both ranked Zesty Paws first.
- Cat litter: Dr. Elsey’s, 87, ahead of World’s Best Cat Litter at 73.
Zuke’s is named in 10% of answers overall.
Where do the engines get their pet advice?
The engines cited 208 sources from 125 websites, and the brands’ own sites supplied 4.8% of them. PetMD was the most cited publisher, with 11 citations across 7 questions, and all three engines cited it. ChatGPT drew 71.6% of its citations from general blogs and publishers. Google Shopping cards made up 21.3% of AI Overviews’ citations.
Gemini is the odd one out. It cited sources in 6 of its 10 answers, and 25.5% of its citations went to authority sources such as aafco.org, the site of the Association of American Feed Control Officials, and cornell.edu. Each of those two sites was cited three times in all. Whether those sources shaped which brands Gemini put first, the data does not say.
What does this mean for pet brands?
I read pet as two markets sharing one category. The main food questions are a three-brand contest, and even there the engines do not agree on the most basic question. Everything else (treats, litter, flea control) goes to whichever brand owns that one need.
For brands here, the source list doubles as a to-do list. PetMD is cited by every engine. Gemini gives weight to feed-standards bodies and universities, sources that brand content teams rarely treat as AEO targets.
The question to track in November is dog food, where one engine changing its pick would break the tie. The full results are in the full October 2026 report.
How we measured: We asked ChatGPT, Gemini and Google AI Overviews 10 non-branded pet product buying questions, giving 30 answers, collected on 21 October 2026 from a single U.S. location. AI answers vary by time, place and user. The full method and notice are in the report.
Sources
- Answer Engine Daily AEO Index: Pet Products, October 2026
