👀 Eavesdropping

Learn whether dogs favor generous people over selfish ones, whether grass eating is a problem, and who won the world’s ugliest dog contest 2025.

👋 Hi, and welcome back to my free newsletter where I share hand-selected dog research, news, and tips every week.

In this week's edition, you will learn whether dogs favor generous people over selfish ones, whether grass eating is a problem, and who won the world’s ugliest dog contest 2025.

Enjoy reading! ✨

📑 STUDY

Generous or selfish?

A recent study calls into question the notion that dogs can assess a person’s character based on how that person treats others.

Researchers investigated whether pet dogs could develop “reputations” of people after either observing them interact with another dog or interacting with them directly.

Across all age groups, dogs showed no consistent preference for a generous food-giver over a selfish one, suggesting that reputation-building in dogs may be more limited, or more difficult to detect, than once believed.

The research addressed a long-standing question in animal cognition: can domestic dogs socially evaluate people in ways that influence whom they approach?

Previous studies have produced mixed results, but few have compared age groups directly or tested both direct interaction and observational “eavesdropping” in the same experiment.

“I’ve always been fascinated by how animals think and behave. As a comparative psychologist, I study social cognition in group-living mammals to better understand the mental processes behind their interactions—and what that might reveal about our own behaviour. This study was part of my PhD project on social eavesdropping in dogs, wolves, and elephants,” said study author Hoi-Lam Jim, a postdoctoral researcher in the Yamamoto Lab at the Institute for the Future of Human Society at Kyoto University.

“We conducted this study as a follow-up to our earlier work (Jim et al., 2022), in which we tested pack-living dogs and wolves at the Wolf Science Center in Austria. These animals’ life experiences differ significantly from those of pet dogs. That study also found no evidence of reputation formation, but it remained unclear whether the negative results reflected cognitive limitations or differences in life experience.”

“With the current study, we aimed to disentangle the role of ontogeny in dogs’ social evaluation abilities by testing pet dogs of different ages,” Jim explained. “We predicted that older dogs would perform better due to greater experience with humans.”

Forty pet dogs of various breeds and ages were recruited from a volunteer database and divided into three groups: young (1–3 years), adult (4–7 years), and senior (8–12 years), with age used as a proxy for lifetime human experience.

The experiment had three conditions. In the eavesdropping condition, dogs observed two unfamiliar women interacting with a “dog demonstrator”, one generous with food, the other withholding it and turning away.

The control condition repeated the actions without a dog present, to rule out reactions to human gestures or tone.

In the direct experience condition, the participating dog interacted with both generous and selfish partners in turn.

Testing was conducted in an outdoor enclosure, with measures in place to avoid bias from experimenter positioning, clothing, or owner influence (owners wore blindfolds).

Researchers recorded which person the dog approached first and how much time was spent on affiliative behaviors like staying close or making eye contact.

Statistical models compared results across conditions and age groups, accounting for trial order and potential side or color biases.

Contrary to predictions, no age group showed a group-level preference for the generous partner in any condition.

Only three dogs, two seniors and one young, consistently favored one person, and one actually preferred the selfish partner. Age did not correlate with performance, and repeated exposure did not make dogs more likely to choose generosity.

About a third of the dogs displayed a persistent side bias, likely due to a shaded area in the testing space, but removing these cases did not alter the results.

“Our results did not provide clear evidence that dogs can form reputations of humans, either through direct interactions or by observing third-party interactions (eavesdropping),” Jim told PsyPost.

“This suggests that pet dogs may not form quick judgements about people, and that reputation formation may be quite cognitively demanding for animals.”

“While it wasn’t surprising that dogs didn’t show signs of eavesdropping (since that ability is more cognitively complex), it was unexpected that we also didn’t find evidence for direct reputation formation. It seems intuitive that dogs would prefer someone who feeds them over someone who withholds food, so it was surprising that we couldn’t even demonstrate this basic preference in our study.”

The researchers propose several explanations. Dogs may require more repeated interactions than this experiment provided; chimpanzee studies, for example, sometimes involve dozens of trials before a clear preference emerges.

The visual differences between the partners, such as clothing colors, may not have been distinctive enough.

Dogs might have formed impressions but chosen not to act on them in the low-stakes environment, particularly since pet dogs typically experience positive treatment from strangers and were not food-deprived.

Outdoor testing could also have influenced the outcome, introducing distractions and environmental variables, like the sun–shade imbalance, that could sway choices regardless of partner behavior.

Laboratory settings eliminate such factors but at the cost of ecological realism.

“Although we didn’t find evidence that dogs form reputations of humans in our study, that doesn’t mean they lack the capacity,” Jim noted.

“It’s possible that the experimental design, such as the two-choice paradigm, didn’t fully capture how dogs evaluate others. We also can’t rule out the possibility that dogs did form reputations internally but didn’t express their preferences in a way we could detect.”

The team suggests future work should compare dogs from different living situations—such as free-ranging populations, shelter dogs, and working animals- to determine whether life experience affects their ability to evaluate humans.

They also recommend focusing on negative behaviors in future tests, as some studies have found animals are more likely to avoid unhelpful or unfriendly individuals than to seek out helpful ones.

Photo by James Lacy on Unsplash

 💊 HEALTH

Eating grass

If you’ve ever caught your dog or cat nibbling on grass, you are not alone. My dog loves eating grass, especially the early spring grass and after it has rained.

For cats, who are strict carnivores, it can seem like an especially odd snack choice. So, what’s behind this leafy habit?

"There's quite a few theories," said Dr. Jamie Lovejoy, a veterinarian at Stack Veterinary Hospital in Syracuse, New York.

"We do see grass-eating behavior in both dogs and cats, and these are two species that technically really don't have the equipment to digest a lot of grass."

Unlike true grass-eaters, pets don’t have the specialized gut bacteria, multi-chambered stomachs, or extended digestive tracts needed to fully break down cellulose.

One popular explanation is that pets munch grass to soothe an upset stomach, Lovejoy explained. "Most of the time when it comes out, it comes out kind of unchanged, either by vomiting or defecation," she said. "And so I think it inspires a lot of old wives' tales."

But research indicates that illness explains only a small portion of grass-eating incidents in cats and dogs.

A 2008 survey of 1,571 dog owners found that 68% reported their pets ate plants daily or weekly, yet only 8% saw signs of sickness beforehand.

Similarly, two 2021 surveys of cat owners revealed that just 6% of cats in one survey and 9% in the other appeared ill before eating grass.

While 27% and 37% of cats in those surveys vomited afterward, many were frequent grazers—71% of owners in one survey saw their cats eat plants at least six times.

The 2021 research also challenged the idea that cats eat grass to expel hairballs. Although long-haired cats tend to cough up hairballs more often, the study found "no evident difference" in grass-eating frequency between long- and short-haired cats.

Grass consumption isn’t just a domestic pet quirk; it’s been observed in wild canines and felines too.

This points to an instinctive behavior, possibly linked to parasite control in the wild. "I think it's a little bit of a hard theory to test, at least in the United States … because most of our pets really don't have these high worm burdens," Lovejoy noted. "So it'd be hard to see."

Although grass has "no apparent nutritional value," according to the author of the 2008 study, some researchers suggest pets might seek it for micronutrients like B vitamins, said Dr. Lori Teller, a clinical professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences.

Still, for healthy pets on a balanced diet, that’s unlikely to be the reason, unless there’s an underlying health problem.

"If you have a healthy pet who is getting a well-balanced diet and occasionally decides to go eat some grass, nibble on catnip, things like that, then [there's] absolutely nothing to worry about," Teller told Live Science.

"If they're ravenous for these plants, or constantly eating them, or constantly eating them and then throwing up, then I would certainly be looking for an underlying problem."

Lovejoy noted that there’s limited scientific research on grass-eating in pets, largely because it rarely causes serious health problems, and veterinary studies tend to focus on more urgent medical issues. "I think a lot of these questions are kind of technically unanswered," she said.

Her own view is straightforward: pets eat grass simply because they want to, whether for the taste, curiosity, or sensory stimulation. "There is no one reason why cats and dogs want to or choose to eat grass," Teller said. "There are probably as many reasons as there are different types of grass out there. Some dogs and cats just like it."

While the behavior is generally harmless, pet owners should be aware that some plants are toxic.

Lovejoy advises checking the American Society for the Prevention of Cruelty to Animals’ database of plants dangerous to pets.

Chemically treated plants can also pose risks, so care should be taken with pesticides and fertilizers. And if a pet vomits frequently or has unusual stools, Teller recommends a veterinary check-up.

📰 NEWS

World’s ugliest dog

Petunia took home the crown at the 2025 "World's Ugliest Dog" competition on Aug. 8, proudly standing beside her owner, Shannon Nyman.

The "World's Ugliest Dog" contest, held at the Sonoma-Marin Fair, has been celebrating uniquely charming pups of all shapes, sizes, and breeds for nearly half a century.

Over the years, dogs with toothless grins, drooping tongues, patchy coats, missing eyes, crooked legs, and other quirks have strutted their stuff, proving that beauty comes in many forms.

Though lighthearted in nature, the event carries a heartfelt message: every dog is lovable and beautiful, no matter how unconventional their looks.

It also champions the value of adopting rather than buying from breeders, as many contestants are rescues from shelters or puppy mills.

In 2024, the title went to Wild Thang, an 8-year-old Pekingese from North Bend, Oregon, who finally triumphed on his fifth attempt.

Surviving distemper as a puppy left him without properly grown teeth, causing his tongue to hang out at all times. One of his front legs also moves constantly, but to fans, he’s flawless.

Wild Thang and his owner, Ann Lewis, shared that he was reveling in his celebrity status. Upon arriving in New York City for the show, his arrival turned into a mini media event.

“We got bombarded. He was just loving it,” said Lewis. “He was wagging his tail. He was happy. He was getting head shots with people.”