“This is the migratory route of the gray whale,” Marina said, helping her father pin down the corners of the map with large conch shells so it wouldn’t curl up again.

Rio couldn’t quite see how this was connected to White Beak, but he nodded anyway. He would sit and listen to anything right now if it meant getting closer to his mom’s whale.

“At the top here is Alaska,” Birch explained, pointing to the largest state of the US, which actually sat above Canada. “That’s in the Arctic, and that’s where the gray whales eat krill that you only find in cold water.”

“Some whales are top-feeders, which means they eat their food on the surface of the water. But others, like the gray whales, are bottom-feeders. They open their mouths like this”—Marina stretched her mouth wide—“and then they scrape it along the bottom of the seabed and shovel tons of krill in.”

Birch nodded. “That’s a great impression, Marina. You’ll make a great whale yet. Although, I don’t recommend mimicking one at the dinner table anytime soon.”

“After feeding,” Marina continued, purposefully ignoring her dad’s teasing, “the whales swim the entire length of the Pacific coast, from Alaska through to Canada and then all the way down the west coast of America, past Washington, Oregon, and California, where we are, and finally down to the lagoons in Mexico.”

Rio looked at the distance. Even on the map, it seemed an impossibly long way.

“It’s a ten thousand-to-twelve-thousand-mile round trip,” Marina said as if reading his mind. “It’s one of the longest migration routes of any animal on earth. And no one really knows how they even do it—how they manage to find their way and don’t get lost or anything. It’s like they carry a map of the ocean in their minds. Gray whales are way smarter than us, even with all our technology. They do it every single year. There and back.”

“Why?” Rio asked, feeling tired just thinking about it.

“In summer, they need to feed in the Arctic because that’s where all the krill is, but come fall, they have to travel farther south, where it’s much warmer, to have their calves.” Birch pointed to three or four bodies of water that looked like estuaries cutting into the coastline of Mexico. “For thousands of years, that’s where the gray whales have traveled—to these shallow lagoons, which are far safer places for them to give birth than in the open water. Then, when the calves are strong enough, the mothers and the calves will swim all the way back north again.”

At that point, the milk started to bubble. While Birch mixed in the chocolate powder and served up the kind of frothy hot chocolate Rio loved best, Marina removed the notebook—the one with all the strange numbers and squiggles—from one of her pockets. “See this? As the gray whales pass by Ocean Bay, we make a note of any we spot.”

“I thought you were just watching them?” Rio asked, confused.