Cockapoos top the list: designer crossbreeds show more problem behaviors than purebred parents

PLOS / Royal Veterinary College, UK

The pitch is familiar: cross a poodle with a Labrador, a cocker spaniel, or a Cavalier King Charles spaniel, and you get a dog that is smarter, calmer, better with kids, and hypoallergenic to boot. Millions of buyers have accepted that pitch. The popularity of so-called designer crossbreeds - labradoodles, cockapoos, cavapoos - has surged worldwide over the past decade, driven partly by the belief that mixing breeds produces temperamentally superior pets.

A new study of more than 9,400 dogs in the United Kingdom suggests that belief is largely wrong.

Cockapoos scored worse in 16 out of 24 behavioral comparisons

The research, published in PLOS One on March 19, 2026, compared three popular poodle crosses - cockapoos, cavapoos, and labradoodles - against their purebred parent breeds across 12 behavioral traits. The tool used to measure those traits, the Canine Behavioural Assessment and Research Questionnaire (C-BARQ), is one of the most established instruments in canine behavioral science. It covers everything from aggression and excitability to separation anxiety and trainability.

The results were not kind to the designer dogs. In 44.4 percent of all comparisons, the crossbreed displayed more undesirable behaviors than its purebred parent. In only 9.7 percent of comparisons did the crossbreed come out better. The remaining 45.8 percent showed no notable difference.

Cockapoos - the cross between cocker spaniels and poodles - fared worst. They scored higher than their parent breeds in 16 out of 24 behavioral comparisons, including owner-directed aggression, stranger-directed aggression, and excitability. That is not a small margin. It means cockapoos were measurably more aggressive toward their own owners and toward strangers than either cocker spaniels or poodles tested on the same scale.

Cavapoos and the separation problem

Cavapoos - the cross between Cavalier King Charles spaniels and poodles - showed a different pattern but still trended negative. They scored worse than their parent breeds in 11 out of 24 behavioral comparisons, with particular problems in excitability, separation-related behaviors, and dog-directed fear. Given that Cavalier King Charles spaniels are already known for attachment-related issues, the finding that crossing them with poodles may intensify rather than dilute those traits is worth noting.

Labradoodles came closest to breaking even. They scored worse than their parents in five behavioral comparisons but better in six, including showing less owner-directed and dog-directed aggression than purebred poodles. Still, the overall picture offers little support for the idea that labradoodles are reliably better-behaved than their parent breeds.

The assumption that crossbreeds inherit the best of both

The widespread belief in crossbreed superiority rests on a misunderstanding of how genetics works. The idea - sometimes called "hybrid vigor" or heterosis - is real in some biological contexts. Crossing two genetically distinct populations can produce offspring that are more robust than either parent. But heterosis applies primarily to traits like disease resistance and overall physical fitness. It does not guarantee that behavioral traits will blend in favorable ways.

Behavior in dogs is shaped by a complex mix of genetics, early socialization, training, and environment. When you cross two breeds, you do not get a predictable average of their temperaments. You get a roll of the dice, with outcomes that can land anywhere within the range of both parents - or sometimes outside it.

The study's lead author, Gina Bryson of the Royal Veterinary College, and her colleagues point out that this unpredictability is itself a problem. Purebred dogs, for all their health issues, come with relatively well-documented behavioral profiles. Breeders and buyers know roughly what to expect from a Labrador or a cocker spaniel. Designer crossbreeds, by contrast, come with marketing claims but very little behavioral data.

What the survey can and cannot tell us

Several limitations deserve attention. The study relies on owner-reported survey data, not direct behavioral observation. Owners of designer crossbreeds may have different expectations than owners of purebreds, which could color how they report behaviors. An owner who bought a cockapoo expecting a calm, easy dog might rate normal puppy energy as "excitability," while a cocker spaniel owner might consider the same behavior routine.

The study also cannot separate genetic effects from environmental ones. Crossbreed owners may, on average, be first-time dog owners drawn by marketing rather than breed knowledge. They may invest less in early socialization or professional training. The behavioral differences observed could reflect differences in ownership as much as differences in the dogs themselves.

Sample sizes varied across breeds, and the data came exclusively from UK owners, which limits how far the findings can be generalized. The researchers acknowledge these constraints and call for further investigation that includes direct behavioral testing and controlled comparisons.

Finally, the study examined only three crossbreeds. The designer dog market includes dozens of poodle crosses and other combinations. Whether similar patterns hold for goldendoodles, bernedoodles, or maltipoos remains untested.

Rethinking the designer dog decision

None of this means that cockapoos, cavapoos, or labradoodles are bad dogs. Individual variation within any breed or cross is enormous, and plenty of designer dogs live happy, well-adjusted lives with their families. But the study does challenge the narrative that crossing breeds is a reliable path to a better pet.

The researchers argue that wider awareness of potential crossbreed behavior issues would benefit both dogs and their owners. A buyer who understands that a cockapoo may be more excitable and more prone to aggression than a purebred cocker spaniel can prepare accordingly - investing in early training, socialization, and realistic expectations rather than relying on a breeder's promises.

The designer dog market has grown on a story. This study suggests the story needs updating.