Like a researcher studying an ant farm, Rutgers University political science professor Ross Baker put a magnifying glass to Capitol Hill and found an interesting pattern of alliances and hatreds that he documents in a forthcoming book, Friend and Foe in the U.S. Senate.

More than a year ago some of his initial findings were listed in this column, but now Baker talks about more specific social groupings in the institution he finds strangely anti-social.

"There's not a hell of a lot of fraternization among senators, not like the House, where groups of congressmen pal around together," Baker says. The good old days when the Senate was dominated by what Lyndon Johnson called "the whales," he says, are gone. The result is a looser institution whose norms and mores are less clear.

But here are some senatorial social groupings Baker found:

Tennis regulars: Lloyd Bentsen (D-Tex.), Jacob Javits (R-N.Y.), Lowell Weicker (R-Conn.), Howard Baker (R-Tenn.), Bennett Johnston (D-La.) and Ernest Hollings (D-S.C.).

Karate practice: Quentin Burdock (D-N.D.) and Ted Stevens (R-Alaska).

Senators of the same party and state who feud: Richard Schweiker and John Heinz (R-Pa.) and Mark Hatfield and Robert Packwood (R-Oregon).

Loners: Robert Byrd (D-W.Va.), William Proxmire (D-Wis.) and Alan Cranston (D-Calif.).

Predominant school backgrounds: Harvard (18 members), Yale (8), Columbia (4) and Princeton (2).