Highly Variable Bot Visits - normal?

[pomra]

We reasonably saw about 60% of our pages scanned on any given day by various google bots. This was pretty consistent with a major drop to about 5% that lasted 2 or 3 days a month ago only to be picked right back up again at the normal rate. About 3-4 days ago the traffic really slowed again from the bot with the major change being a different IP doing the digging. Is this fairly normal? There have bee no other problems, I just didn't know if this was a precursor to something going on.

Thanks

[incrediblehelp]

If their are no problems then what is the problem?

Spider activity going up and down like this is OK.