Safari and .dat files?

Just noticed that in the ~/Library/Safari folder there may or may not be some files starting with .dat (you need to be able to see hidden files from the Finder to see them -- or using ls via terminal ). Does anybody know what these files are? For instance: drwx------ 11 user1 staff 330 Feb 26 16:15 ./ drwx------ 53 user1 staff 1758 Feb 12 11:33 ../ -rw------- 1 user1 staff 6148 Feb 26 15:42 .DS_Store -rwx------ 1 user1 staff 0 Nov 27 10:37 .dat0101.9e7* -rwx------ 1 user1 staff 0 Nov 27 10:55 .dat0101.bb9* -rwx------ 1 user1 staff 0 Nov 27 10:55 .dat0101.bc2* -rwx------ 1 user1 staff 0 Nov 27 10:56 .dat0101.c69* -rwx------ 1 user1 staff 49259 Feb 26 10:56 Bookmarks.plist* -rw-r--r-- 1 user1 staff 21706 Feb 21 10:26 Downloads.plist -rw-r--r-- 1 user1 staff 115816 Feb 26 16:15 History.plist lrwxr-xr-x 1 user1 staff 9 Feb 26 15:42 Icons@ -> /dev/null