All puppies are cute, but at some point in a young dog's life, it goes from "It's so cute I could squeeze it to death" to merely regular cute. But when? According to one recent study in the journal Anthrozoös, peak cuteness hits between 6 and 8 weeks old for many dogs, The Washington Post reports.

Finding out when puppies reach their peak attractiveness to humans may give us insights into how domestic dogs evolved. Researchers from the University of Florida asked 51 students at the school to look at 39 black-and-white images of dogs, who belonged to three different breeds and whose ages ranged from birth to 8 months. The viewers then rated them on a sliding scale of squishability.

The results will sound familiar to dog lovers. Puppies aren't entirely adorable immediately after they're born—they can look a little rat-like—and the participants rated them accordingly. As dogs get older, as much as we might love them, their squee-worthy cuteness declines, as the attractiveness scores reflected. The sweet spot, it turns out, is right around when puppies are being weaned, or between 6 and 8 weeks old.

The participants tended to rate dogs as most attractive when the pups were within the first 10 weeks of their lives. According to the results, Cane Corsos were at their cutest around 6.3 weeks old, Jack Russell terriers at 7.7 weeks old, and white shepherds at 8.3 weeks.

The study only used still photos of a few breeds, and it's possible that with a more diverse sample, the time of peak cuteness might vary a bit. Certain puppies might be cuter at an older age, and certain puppies might be cuter when they're even younger. But weaning age happens to coincide with the time when puppies are no longer getting as much support from their mothers, and are thus at a high risk of mortality. By evolving to attract human support at a time when they're most vulnerable, puppies might have boosted their chance at survival until they were old enough to completely take care of themselves.

[h/t The Washington Post]