After a day of farewells drawn out by procedural delays, the three aging elephants that left the Toronto Zoo for California crossed the Canada-U.S. border early Friday morning.

Toronto Zoo spokesperson Jennifer Tracey said the convoy of trucks carrying the pachyderms crossed the border at approximately 5:30 a.m. She said Toka, Thika and Iringa are doing well.

"We are extremely proud of the Toronto Zoo staff who have been so dedicated and committed to these three animals over the years, but particularly for their professionalism throughout the load process which was also a very emotional time," a release from the Toronto Zoo said Friday.

The elephants left the Toronto Zoo at approximately 10:30 p.m. Thursday night, after long delays which saw the animals parked in two-by-four metre crates for hours. Canadian Food Inspection Agency officials arrived on site to inspect the elephants' health before they were scheduled to leave at 2 p.m.

The trip to the Performing Animal Welfare Society sanctuary in Galt, near Sacramento is expected to take at least 50 hours.

Toronto city council voted in 2011 to relocate the animals after years of pressure from animal rights activists.

The move was delayed several times as officials disagreed on how to best transport the pachyderms. The latest disagreement surrounded a non-disclosure agreement provided by Active Environments, the company hired to move the elephants.

Active Environments wanted zoo workers appointed to accompany the elephants on their journey to sign an agreement that prevented them from revealing any details about the U.S. leg of the trip. The zoo workers' union, CUPE Local 1600, refused.

But in a deal reached Thursday morning, the non-disclosure agreement was taken off the table and the zoo workers were allowed to accompany the elephants.

Four Toronto Zoo staff members who have been working with the elephants are travelling with the convoy to California.