Despite its title, ''The Squid and the Whale" isn't a nature documentary. No, wait, maybe it is. Set in the wilds of Brooklyn's Park Slope, still largely an undiscovered continent in 1986, Noah Baumbach's memory tale is a wry, pain-wracked study of animal un-mating habits and the survival techniques of the newly fledged. The fauna on display is one dissolving family headed by an imposing silverback male -- played in an unforgettable, career-peak performance by Jeff Daniels -- and the movie's lasting sting belies its brief 80 minutes. This is one cinematic novella that stays with you for quite a while.
Baumbach co-wrote Wes Anderson's ''The Life Aquatic With Steve Zissou" (Anderson serves as producer on ''Squid"), but this time out he sticks closer to home, reworking his own memories as a child of divorce into a small, sharply observed period piece. When we meet married writers Bernard Berkman (Daniels) and his wife, Joan (Laura Linney), it's pretty much over except for the shouting and the paperwork. The end has been hastened by her infidelity and his arrogance, his fading literary career and her sudden success (the director's real parents, in case anyone's keeping score, are novelist Jonathan Baumbach and film critic Georgia Brown).
The final split comes as a shock to the Berkmans' two sons, gangly teenager Walt (Jesse Eisenberg, the kid from ''Roger Dodger") and Frank (Owen Kline), a tweener on the cusp of adolescence. In the words of one of Walt's friends, ''joint custody blows," and this is even before Walt learns his mom once slept with the friend's dad. ''The Squid and the Whale" is ruthlessly honest about the romantic delusions of post-'60s yuppie bohemians -- how one person's ''freedom" is usually paid for in the misery of everyone else within strafing distance. (All right, the title comes from an exhibit at the New York Natural History Museum, even though it could just as easily apply to the psychic tussle between Mom and Dad).
The children take sides, as children will: Gentle, messed-up Frank clings to his mother, earnest Walt to his father. Anyway, who wouldn't want a cool dad like Bernard, a bearded academic cynic who name-drops Norman Mailer and has a superior opinion about everything (especially literature and tennis)? When a cute classmate (Halley Feiffer) praises ''Tender Is the Night," Walt can say with confident hauteur that the book is ''minor Fitzgerald" because that's what Pop has taught him. He doesn't need to read the book to know that.
''The Squid and the Whale" catches the widening fallout -- Bernard's emergence as a Bad Dad of the first rank, Frank's tailspin into liquor and weird sexual behavior, Walt's flirtations with plagiarism and hubris -- but it somehow retains a keening comic tone. It's funny that both Bernard and Walt get a crush on one of the father's writing students, a posturing temptress named Lily (Anna Paquin); it's funnier still that her oversexed prose is so bad. The situation turns pathetic only when Bernard makes a move.
This is Baumbach's third film as director (he made 1995's ''Kicking and Screaming" and 1997's ''Mr. Jealousy") but it's his first personal one, and maybe that's why the camerawork seems overly shaky -- fictionalizing family demons might make anyone's hands tremble. The sense of time and place is spot-on, though, and the rueful tone is nicely abetted by a score written by Dean Wareham and Britta Phillips of the late, lamented rock group Luna.
Better yet, all the performances are exquisitely life-size, including William Baldwin as a hipster neighborhood tennis pro. The exception is Daniels's, which is as it should be: Bernard is a huge, charismatic false front behind which lives a terribly small man.
That said, Linney carries off the more subtle task of making Joan flawed and sympathetic -- a woman so weary of living in the shadow of a literate bully that she makes stupid choices. ''The Squid and the Whale" is the story of Walt's coming to terms with who his father and mother really are and who he stands to be. Not gods, fallen or otherwise. Not animals. Simply humans.
Ty Burr can be reached at firstname.lastname@example.org.