What’s wrong with this sentence?

Last week I received a press advisory from the Proceedings of the National Academy of Sciences that began:

"A hamster-size dose of sildenafil, known as Viagra, helps the rodent recover more quickly from a six-hour advance in its daily cycle, researchers report."

A hamster-size dose of Viagra? Yikes, that better not be a suppository.

Contexts, a publication of the American Sociological Association, was more careful with their representation of appropriate dosage when they captioned the following image last year (volume 5, number 2, page 41):

Actual size

The academic periodical played a bit more fast and loose in captioning the image of Bob Dole on the following page:

But who can blame them? That’s totally my favorite kind of joke: one that combines Viagra, invalids, and bestiality.