And they didn’t even say goodbye.
After Bay Area residents went to bed having heard that two wayward humpback whales were near Tiburon, they woke up to find the leviathans were long gone Wednesday morning. The now-famous mother and calf, Delta and Dawn, were assumed to have made it to the Pacific Ocean on Tuesday night after searches Wednesday in the Bay and on the open ocean were fruitless, search officials said.
The last official sighting of the whales was at sunset Tuesday, four miles south of the Richmond-San Rafael Bridge, east of Tiburon. The whales were swimming toward the ocean and against the tide, Coast Guard officials said.
Their departure brings to an end a nationwide infatuation not seen since “Humphrey” the humpback whale showed up near Rio Vista in 1985. Their active and unpredictable stay in the Bay Area allowed scientists to study the whales in close proximity, something that is extremely rare due to the animals’ nature.
Sarah Wilkin, a marine mammal biologist with the National Oceanic and Atmospheric Administration, said scientists were able to study such things as the whales’ behaviors, activities, breathing rate and movements.
“One thing that’s been kind of curious is their movements in relation to the tides and currents,” Wilkin said.
Marine biologists were able to come away with biopsies from both animals — the results of which should be available today — and skin scrapes, Wilkin said. Both should provide more insight into the health of the whales.
Sightings began May 9, but authorities began taking serious note of the humpbacks May 13 when the Solano County Sheriff’s Department received reports of two whales in the Sacramento-San Joaquin River Delta near Rio Vista.
Delta and Dawn ventured much further inland than Humphrey, swimming some 90 miles from the Golden Gate Bridge to a turn basin near the Port of Sacramento. Rescuers tried different tactics to reverse the whales’ course: playing humpback whale songs and killer whale noises, banging pipes and spraying fire hoses.
The whales finally began their journey back out to sea May 20, stopping occasionally at area bridges before presumably swimming under the Golden Gate Bridge on Tuesday night under cover of darkness.