MULEGÉ: A giant barnacle-encrusted gray whale nuzzles her calf next to a small boat of excited tourists in the waters off the Baja California peninsula in northwestern Mexico.

The annual arrival of the migratory mammals, coinciding with a drop in coronavirus infections, has provided a much needed boost to the region's battered tourism industry.

For visitors, close encounters with one of the largest animals on the planet are a welcome respite from a pandemic that has killed more than 200,000 people in Mexico -- the world's third highest toll.

"It's the best day of my life," said Wilbert, a Mexican tourist who traveled from the southern state of Oaxaca to a coastal wildlife sanctuary in Baja California.

"I had dreamed of whales before so I was really keen to come."

Each year, gray whales travel about 9,000 kilometers (5,500 miles) from their summer feeding grounds off Alaska to mate and give birth in the warmer waters off northwestern Mexico.

Similar in size to a humpback whale but recognizable from their mottled grey coloring, they span up to around 15 meters (46 feet) and weigh as much as 30-40 tons.