When 39-year-old filmmaker Spike Jonze began visiting author and illustrator Maurice Sendak at his Connecticut farmhouse years ago, Sendak often spoke of how his Jewish immigrant relatives inspired the toothy monsters in his children’s classic, “Where the Wild Things Are.”

“Maurice was afraid they would eat him up,” said Jonze, whose film adaptation of the book opens this week. An exhibition of Sendak’s work, “There’s a Mystery There: Sendak on Sendak,” is currently on display through Jan. 19 at the Contemporary Jewish Museum in San Francisco.

During those conversations around the dining room table in Connecticut, Sendak described how the book actually began as another children’s project, titled “Where the Wild Horses Are,” which tanked when Sendak discovered he couldn’t draw a horse to save his life.

When his publisher acidly asked what he could draw, Sendak flashed back to his immigrant relatives, who had fled Poland before the Holocaust and regularly invaded his Brooklyn home to devour everything in sight.

Director Spike Jonze carries actor Max Records, who plays Max, on the set of “Where the Wild Things Are.” photo/sonny geras

“These people didn’t speak English,” he said in “Heads On and We Shoot,” a book about the making of the movie. “They were unkempt. Their teeth were horrifying. Hair unraveling out of their noses. And they’d pick you up and hug you and kiss you, saying, ‘Aggghh. Oh, we could eat you up.’ ”

In Sendak’s 1963 classic — a groundbreaking effort that did not play down children’s real fears — the Wild Things recall his Jewish aunts and uncles, albeit with claws and rolling yellow eyes.

“That’s what art is,” Sendak said. “You don’t make up stories. You live your life.”

Jonze (born Adam Spiegel) took this advice when he signed on to adapt the book.

“Maurice urged me to make Max’s story my own,” he said during an interview at the Beverly Hilton Hotel, where he wore sneakers with his suit and boyishly slouched in his chair. “Maurice said, ‘You make this personal, you make this dangerous, you do not pander to children, and don’t be overly reverential to the book.’ ”

While the Max of the book is “incredibly brave, fierce, mischievous and loving — just like Maurice,” Jonze said, the movie’s Max is more vulnerable, hearkening back to the filmmaker’s own days as the sensitive child of parents who divorced when he was 2.

Jonze won’t discuss much more personal information, including his own Jewish background — though he has admitted to being the great-great grandson of Joseph Spiegel, who founded the Spiegel catalogue at the turn of the 20th century and was the son of a German rabbi.

Jonze got his start in the skateboarding scene before becoming a maker of influential music videos and two surreal but critically acclaimed films: 1999’s “Being John Malkovich” and 2002’s Oscar-winning “Adaptation.”

But it was before he made either of those movies, in 1994, that he met Sendak, who is 42 years his senior: Sendak’s film company had hired him to adapt the children’s book “Harold and the Purple Crayon,” which never came to fruition. But a friendship blossomed between the two artists, despite their age difference.

“When I first met him I was 25, and I loved him, but I didn’t have the same conversations that we would have when I was in my 30s — I hadn’t yet been through that much,” Jonze said, alluding to his divorce from filmmaker Sofia Coppola in 2004. “He is wise and experienced, but he never stops questioning, or struggling.”

“Where the Wild Things Are” opens Friday,  Oct. 16 in theaters around the Bay Area.