LOS ANGELES — Billy and Tina, the last remaining elephants at the Los Angeles Zoo, were quietly moved this week to a zoo in Oklahoma despite pending lawsuits seeking to have them transferred instead to an animal sanctuary where they could live out their days with more room to roam.

The announcement last month that Billy, 40, and Tina, 59, would be sent to the Tulsa Zoo angered animal advocates who argue that they would be subjected again to an enclosure that’s too small for aging elephants.

The move came “under cover of darkness,” said Jake Davis, an attorney for the Nonhuman Rights Project. Davis said he received reports that the Asian elephants were transferred out about 1:30 a.m. Tuesday to elude protesters who’ve been staking out the zoo.

The nonprofit on Tuesday filed a petition asking a court to release Billy and Tina from the LA Zoo and send them to one of two accredited sanctuaries appropriate for elephants where they would have full-time care and ample space.

“At a sanctuary, they could live as nature intended,” Davis said Wednesday. “They need massive swaths of land; they need varied terrain.”

The LA Zoo said in a statement Wednesday that the elephants “have arrived safely at the Tulsa Zoo” but didn’t say when the transfer occurred.

The move was necessary because the Tulsa Zoo has other Asian elephants who will provide important socialization for Billy and Tina because “keeping them in larger groups is crucial for their well-being,” especially at their advanced age, the LA Zoo statement said. Asian elephants typically live around 60 years.

A move to a sanctuary was considered, but the Tulsa Zoo was the top recommendation based on the standards of the Association of Zoos and Aquariums’ Elephant Species Survival Plan, which considers “space, herd dynamics, and expertise of the staff,” the LA Zoo said.

“This option also ensured that Billy and Tina would be able to remain together,” the statement said.

Davis said he expects the Los Angeles lawsuit will be dismissed but his group will not give up the fight to get Billy and Tina a sanctuary retirement home. He said his team is exploring legal options in Oklahoma. The Tulsa Zoo didn’t immediately reply to a request for comment.

A lawsuit filed this month by an LA resident sought to halt the elephants’ transfer, but a judge denied an emergency motion for a temporary restraining order. That lawsuit includes a declaration by the singer Cher, who has advocated for the elephants for years, the Los Angeles Times reported.

“Billy and Tina have served their time in confinement,” Cher said in the declaration. “They deserve the chance to live out their lives in peace and dignity.”

The LA Zoo referred questions about the court actions to the city attorney’s office, which said it doesn’t comment on pending litigation.