Back to Cabo Expeditions Blog

Why Wintertime Is Cabo Whale Watching Season

an animal swimming in the water

Wintertime is whale watching time in Cabo! Whale watching season gets underway in December, as whales come from far away in great numbers. They come for the sun. They come for the warm, sweet water of Cabo. They come to breed.

Every winter Cabo welcomes the migrants home to their birthing place, the balmy waters of Baja California Sur. Thousands of whales head south from far north to winter in Baja. They come in droves and swim thousands of miles.

Three big favorites are the stars of the Cabo whale watching seasons: humpbacks, blue whales, and gray whales.

Sex, babies, and rock ‘n roll

The highlight of Cabo whale watching season is the sight of a humpback whale breaching. You can be humming along in a dozy daydream, just watching the diamond sparkles of sunlight on the azure waves. Suddenly a monstrous dark shape surges out of the water, does a back flip, and lands in a brilliant white splash that can be seen for miles.

During the Cabo whale watching season, humpbacks are favorites and easy to identify. You can easily tell a humpback whale by its unique long flippers, up to fifteen feet long—longest “arms” in the animal world. They slap the water with their flippers, sometimes with their flukes (a behavior called “lobtailing”). When they dive, they hump their backs.

cabo whale watching season

How to spot a humpback whale (Image credit: American Cetacean Society)

Pregnant female humpbacks seek the warm waters near Cabo, where the Sea of Cortez makes a perfect nursery for calves. They give birth after an eleven-month pregnancy. The one-ton newborns don’t lose as much energy trying to keep warm, at a time when their small—well, smaller—size and scant blubber puts them at risk in cold water. The mothers support and nurse them with a rich milk that makes them grow rapidly.

“Uncouth gambols” of humpbacks

“Uncouth” is what the notorious whaler and expert, Captain Melville Scammon, called humpbacks. The show-offs throw rockin’ parties with acrobatic breaches that make you gasp. Their aerial displays and sensuous courtship behaviors may have shocked his Victorian sensibilities.

Males compete for female whales and sing long, complex songs. You could see one male hanging close to a female to block a rival. Another may resort to creating a bubble screen to obscure the prize. They may fight, slapping with their tails or jumping on the back of their rival.

They’ve come a long way for the opportunity. Humpbacks can travel great distances. The population that comes to Baja for the Cabo whale watching season comes from the Pacific Northwest. They summer from northern California up to the coast of British Columbia. This population is designated a threatened group, unlike the more secure population that goes to Hawaii from the Bering Sea.

cabo whale watching season

Image credit: Wikimedia Commons

Whalers killed 90% of the species, but with protection humpbacks are slowly recovering. Today the main human threat is lost or discarded fishing nets and lines. When whales get tangled up in them, they can suffer injury or even death by drowning.

Loudest and largest—blue whales

cabo whale watching season

Blue whale (Image credit: American Cetacean Society)

The largest animal that ever lived on earth—the blue whale—also comes for the Cabo whale-watching season. They can grow to 100 feet long. The wide-ranging blues don’t have a predictable migration pattern, so we don’t know exactly where they come from each winter. They’re the loudest of the whales, perhaps because they must communicate across the farthest seas. Their low-frequency sounds travel hundreds of miles.

cabo whale watching season

Blues come for the krill-rich waters of the “Vermillion Sea.” That’s what an explorer called Baja’s Sea of Cortez, because masses of tiny red crab-like krill gave it a ruddy glow.

Longest migration of any mammal

cabo whale watching season

Gray whale (Image credit: American Cetacean Society)

Gray whales routinely travel the farthest of the whales from their Arctic feeding grounds. They feed on small shrimp-like amphipods that thrive in cold waters. They fatten up for the winter and then head south. Many breed on the Pacific coast of Baja, but quite a few come here for the Cabo whale watching season.

You can recognize gray whales by their mottled gray and white hide, rough with patches of barnacles and even orange whale lice growing on their head.

You could see them breach or come close to your boat. Grays seem to be the friendliest whales, poking their heads straight up out of the water the better to see you with, a behavior called “spyhopping.”

cabo whale watching season

The mothers give birth and nurse their calves with milk as thick a yogurt. The calves practice their swimming ability for their long journey ahead to the northern feeding grounds.

Whales are efficient swimmers. Think how hard it is to swim through the resistance of water compared to walking through air on land. Then imagine swimming six thousand miles at least—and back again—every year.

Climate change seems to lead gray whales to feed longer in summer waters north of the Bering Straits. Their southbound migration is starting later. There’s a link between the timing of the melt of seasonal ice in the Bering Sea and the number of calves counted in the following spring. It seems the plankton may be moving further north as ice melts, forcing the gray whales to travel farther to their feeding ground.

Crazy good Cabo whale watching season

These three big migrants—humpbacks, blues and grays—aren’t the only whales in Cabo waters. They join whale species that live here year-round, such as resident sperm whales and fin whales. When the “snowbirds” join the residents, it’s one awesome Cabo whale watching season.

Few other places can boast such a whale bonanza. You could see whales you never knew existed. Thirty-two species of cetacea –whales and dolphins—frolic in these waters.

We include dolphins in the 32-species count because they’re considered by science to be whales, small ones. They are all air-breathing mammals who live their entire life cycle in the sea. A superabundance of cetaceans makes the Cabo whale watching season crazy good.

Diversity of whales in the Sea of Cortez

Their feeding strategies have led whales to evolve different adaptations, depending on the size of their prey. The two main groups are the toothed whales and the baleen whales. The toothed whales have cone-shaped teeth like the teeth of dogs. They prey on fish and squid.

Open wide

Baleen whales suck tiny fish, fish eggs, coral spawn, and microscopic plankton out of seawater. It’s like straining morsels of meat out of soup, Instead of teeth, they have the odd (to humans) structure called baleen. Baleen is a keratin fringe that works like a strainer, retaining small prey from a mouthful of seawater.

Keratin is the material your fingernails are made of. Back in the day, ladies wore corsets ribbed with baleen, so-called ‘whalebone.’ Pleated throats and undersides let Baleen whales open their mouths to huge capacity, taking in enormous quantities of water and everything edible in it. No wonder certain baleen whales, the rorquals, are called “gulpers!”

Baleen whales in the Sea of Cortez include the migrating humpbacks, grays, and blue whales. But they aren’t the only ones. Resident fin whales, Bryde’s whales and minke whales feast year-round on the plankton-rich waters. The fin whale is long, sleek, and streamlined, with a V-shaped head which is flat on top. Rarely seen are sei whales (rare), and once a lost and lonely Northern Pacific right whale was sighted.

cabo whale watching season

Fin whale (Image credit: American Cetacean Society)

Gray whales strain their food through baleen, but they obtain it from muddy sea bottom. They lie on their right side in shallow coastal waters and scrape up a mouthful of mud rich with clams and mussels. Forcing the expelled sediment through the baleen leaves a trail of “mud plumes” floating in the water behind them. They have fewer baleen plates than the other filter feeding whales.

Moby Dick dines here

The most famous of the toothed whales would be the sperm whales of “Moby Dick” fame. They feed year-round in the Sea of Cortez, notably on giant squid.

Add to your list of toothed whale species you could see here: dwarf sperm whales, pygmy sperm whales, false killer whales, and pygmy killer whales. A few killer whales reside here, but most orcas hunt in colder climes. That’s an important fact for other whales, as orcas are truly “whale killers”—the top marine predators. Some say orcas should be called dolphins.

Dolphins are whales, too

Toothed whales in these waters include the smaller whales called dolphins. The Sea of Cortez is dolphin heaven. You could see armies of them galloping across the turquoise sea. You’re sure to see a few up close, checking you out or riding your boat wave.

cabo whale watching season

Bottlenose dolphin teeth

Species of dolphins here in the Cabo whale watching season round out the toothed whales: common bottlenose dolphins; short-finned pilot “‘whale”; the rare winter visitor, the Pacific white-sided dolphin; the pantropical spotted dolphin, Risso’s dolphin (also called the “grampus”), spinner dolphin; the rare melon-headed “whale”; and the striped dolphin.

Dolphins do not seem to migrate in the same way as the larger whales do. During the Cabo whale watching season in winter, you would be unlikely to see the rough-toothed dolphin, a summer visitor.

But for the great baleen whales—the blues, grays and humpbacks—wintertime is whale time in Cabo. To these wise whales of the west, sunny days and warm water sounds better than ice and snow of the short, dark months. You might agree. And decide to join them for Cabo whale watching season.