Every year, gray whales migrate from the Arctic to the warm waters off Baja California, Mexico, swimming and spouting along the California coast as they do, to the delight of whale watchers.
But this year, they seem to be arriving in record numbers - and scientists aren't sure why.
It once was considered lucky to catch a glimpse of a gray whale. After all - they used to be endangered.
But this month, along the California coast, luck is surfacing like never before, reports CBS News national correspondent Lee Cowan.
Marine biologists say there have been nearly 170 sightings of gray whales this month alone -- that's more than four times the normal number - and they're drawing plenty of oohs, ahhs and wows from whale watchers.
Biologists and local whale-watchers say they haven't seen whales in numbers like this in almost 30 years.
"My favorite sound," says Capt. Carl Mayhugh of Harbor Breeze Cruises, "is when people scream -- you hear them screaming and going 'ahh,' and they're just all happy -- that's what makes my day."
The Grays have been captured underwater, as well - some video is already making the rounds on YouTube.
Even from shore, they seem close enough to touch.
One came so close to a whale-watching boat, "We can actually hear the breath," notes Alisa Schulman-Janiger of the American Cetacean Society.
No one knows exactly what the sightings mean -- are there more whales, or are they just closer to shore and easier to spot? What IS known is that the gray whales aren't the only visitors.
Last spring, hundreds of blue whales were spotted off California's coast.
And then there were the humpbacks -- who gave some kayakers the surprise of a lifetime, going under them.
Whatever the reason, at the very least, researchers hope it all means things in the whaling world are going well.
Says Schulman-Janiger, "It could very well mean that more are coming down because they're pregnant and ready to give birth, and others are coming down ready to get pregnant for the next year."
And that leaves whale watchers hopeful that the aquatic traffic jam will get even busier.