Prisoners of Size?

In the short article Size and Shape the late paleontologist and evolutionary biologist Stephen Jay Gould remembers how he once overheard a children’s conversation in a New York playground:  “Two young girls were discussing the size of dogs. One asked: “Can a dog be as large as an elephant?” Her friend responded: “No, if it were as big as an elephant, it would look like an elephant.” And indeed, in many ways it probably would. However, the more important question at this point is if an elephant can be as small as a dog.