Maybe it's keeping a low profile in choppy waters. Or maybe it just got a whiff of the Patapsco River and high-tailed it out of here.
Whatever the reason, the unidentified whale -- spotted Sunday in Chesapeake Bay, just north of the Bay Bridge off the Eastern Shore at Rock Hall -- hasn't been seen since 8 p.m. Sunday.
An aerial search of the bay southeast of Baltimore yesterday morning also failed to spot the animal, and there was no sign of it today.
"It could have simply turned around and gone back to the ocean," said Cheryl Messinger, a marine mammal specialist at the National Aquarium in Baltimore.
Boaters last reported the whale swimming east to west in the bay off Rock Hall Sunday evening. Anyone who sees it is asked to call the Department of Natural Resources marine police at 1-800-628-9944.
Until whale experts can get to the animal and identify it, Messinger said, it's impossible to know whether the whale is in any distress or in need of human assistance.
"Whales have been sighted in the bay before. The unusual part may be that it is north of the Bay Bridge; they are normally found farther down toward the mouth of the bay," she said. This one may have ventured farther north because it is sick, lost, curious or in pursuit of fish.
If the whale is found and identified, no action will be taken to assist it unless it is in distress and the National Marine Fisheries Service authorizes human intervention.
Whales, like all marine mammals, are federally protected.
"We're not allowed to interfere with the animal, and that's what we ask of other people," Messinger said. "Our biggest concern is just to keep people from harassing or startling it."