Some browsers naturally show more hits then others?

Or is this a cache issue?

[JAB Creations]

I'm setting up a statistics script and as I'm testing various builds of various engine based browsers I'm seeing some browsers request over 30 files on initial loading of the stat page itself (mostly tiny images) and others not even getting above 6 hits on their first load. I'm not even seeing 304s or anything yet the images are still loading, a bug in Apache, the browsers?

[John Carpenter]

Some browsers use pre-fetch. That means that it pre-loads some portion of the site, which the user is likely to browse soon.

[Span]

Some browsers aren't browsers at all. They use "Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)" but never request any image, js, or css file.

Another possibilty: regular visitors. They maybe cached some files on an earlier visit.

[dutch_dude]

Probably not the whole answer but most browsers other then IE always request favicon images to display in the location bar.