Image credit: Damian Dovarganes/AP Photo

A dolphin that has made a temporary home in shallow waters off Southern California's coast may have been forced there by a brutish band of other dolphins, says a wildlife expert who tried to steer it toward open water this weekend.

"He was scared. He was intimidated. He was bullied," Peter Wallerstein, director of El Segundo-based Marine Animal Rescue, told The Los Angeles Times.

On Friday morning, the black-and-white common dolphin was found swimming in circles 12 feet from the shore in the Bolsa Chica wetlands south of Los Angeles. Officials told ABC News affiliate KABC Friday that the dolphin appeared disoriented and stressed and could be at risk of suffocating in the low waters.

Wallerstein said Monday that when wildlife rescue crews had tried to help the dolphin move back into the ocean Saturday, a group of dolphins appeared, thrashing around and attacking the loner. Wallerstein said the dolphin eventually retreated back into the channel.

"Dolphins can be very aggressive toward each other," Wallerstein said. "They're not the sweet, loving, gentle animals portrayed by the movies and the cartoons. They do have a dark side."

In March, researchers from the University of Massachusetts, Dartmouth, released the results of a five-year study of more than 120 adult dolphins, with a focus on the males, in Shark Bay, western Australia.

In their findings, scientists said they'd discovered that male bottlenose dolphins formed gangs to protect their females.

Richard Connor, a co-author of the study and a biology professor who has studied these particular dolphins for more than 20 years, told ABC News that male dolphins' social lives were intense.

"They do get in fights. They are in these incredible gangs - we call them 'alliances.' There are big fights between groups over their females," Connor said. "Just like people they have squabbles. Relationships are complicated."

There were no reports yet of a female dolphin being involved in this case.  For now, crews have decided to allow the dolphin in the wetlands to leave when he feels ready.

The Associated Press contributed to this story.