Okay, apparently Sandy isn't as spectacularly cute as I think she is, because no one wanted to look at her long enough to estimate her dimensions.
This makes Sandy sad, but she'll get over it.
But, I did say I would explain the reason for the challenge in a few weeks. Being a woman of my word, I figured I ought to follow through.
All of the people to whom I've sent photos of Sandy who have subsequently met her have remarked on her size. Apparently, people expect her to be quite a bit larger than she actually is. This led my husband and I to wonder how people judge the sizes of objects when they have no reference points. We concluded that Sandy's proportions must be more similar to those of large dogs than to those of small dogs. I was hoping for some independent data to support this hypothesis. Alas, it was not to be.
(end note: Sandy, demonstrating a typical dog attention span, has now recovered from her disappointment.
8 years ago