The massive, 85-foot whale was found washed up on the beach on Monday, with her male fetus just 50 feet away.
"And then to have the fetus over there, it's really unusual," says park ranger Frank Balthis.
The whole scene is extraordinary. The last time a dead blue whale came to shore in this area was more than 30 years ago.
Normally, the only way to see a blue whale is during a whale watching trip in the open ocean. They're too big to hold in captivity and the only blue whale skeletons on display in the state are in Santa Cruz and Santa Barbara.
"I have always wanted to see the biggest animal that's ever lived. It's quite a specimen," says naturalist Jeff Parry.
"It's a rare event, especially to see one, a female -- and a very big female -- and then one that is carrying a fetus, that makes it even more special and unusual," says Pacifica resident Paul Jones.
Someone spotted the carcasses floating in the water on Saturday. U.C. Santa Cruz researchers got their first up close look on Monday, once the bodies came up on the beach.
Preliminarily, scientists don't think the female died naturally. Because she's so healthy, they think a ship's propeller may be to blame, but it'll be several days before they know for sure.
"It's upside down, so if a ship hit it, we can't see the back to know to look for a wound of that. It's so large you can't move it and so it's real difficult to tell," says Balthis.
Blue whale calves are born after 12 months and this fetus was only six months old. The whale was likely swimming south to Baja California for the winter.
According to state rangers, the scientists will take tissue samples of the whale and also do a necropsy to figure out how she died.
After that, no one is going to remove the bodies because the whale itself is just too big, so the plan is to let nature take its course. Animals in the water will eventually break down the carcasses, even though that will take several months. The ranger says that he doesn't expect that to be a problem because that part of the beach where the whale is isn't very popular.