He's like the guy your mother always wanted you to marry - polite, steady, boring.
While his colleagues are beating their chests and chasing females, he's watching visitors and snoozing in the Atlanta sun.
Wake up, Ivan! Macho is in. Passive is out.
That's the word from Zoo Atlanta, where the social - make that the sexual life - of Ivan the gorilla is the latest preoccupation.
The silverback gorilla, who spent 27 years on display at a Tacoma shopping center before being sent to Atlanta in October 1994, has a lot to learn about the opposite sex.
For instance, female gorillas find aggressive, macho males a turn-on, said zoo research associate Kyle Burks. And Ivan, well, his favorite occupation is his Primate Chow breakfast and an afternoon nap on the hill in "Gorilla Paradise."
He's a frustration to Kuchi, the zoo's mate of choice for him. She's known for "sneaking up behind him and poking him in the butt, then running away," said Carol Flammer, zoo spokeswoman. "She's a pest."
Nevertheless, a month ago the zoo gave the two a room of their own, hoping to encourage intimacy.
"Kuchi made him some decent offers," Flammer said.
So far, Ivan hasn't accepted.
It's hard to undo all the years at Tacoma's B & I Shopping Center, zoo officials say. While macho aggressiveness is common in gorilla males, Ivan wasn't raised around other gorillas.
But is 11-year-old Kuchi Ivan's type?
She may be little more than a kid, but "she's had a great deal of social experience with other males," Burks said. And Kuchi's had one offspring.
"We're just giving him his space and time. If things keep going well, (mating) is the next logical step."
Ivan is 33 now, and just how much longer he'd be physically capable of breeding is unknown. Willie B. the other male at the zoo, who spent 27 years in a cage before coming to Atlanta, has sired offspring at 37.