Sperm whale (Physeter macrocephalus), illustration

Protected Physeter macrocephalus

Sperm whale in Los Cabos

The largest toothed whale on the planet hunts jumbo squid in the deep basins of the Sea of Cortez. Near Cabo it’s an occasional, offshore sighting, and one worth stopping for.

Up to 18.5 mLength (males)

~45 tonsWeight (males)

1,500 mDeepest dives tagged in the Gulf

236 dBLoudest click recorded

When to see them

Jan·Feb·Mar·Apr·May·Jun·Jul·Aug·Sep·Oct·Nov·Dec·

●● best months · ● regular · · occasional. Based on scientific studies and local reports; it changes year to year.

Tap a month to see everything biting in Cabo that month ›

How to recognize it

Dark brownish gray with wrinkled skin behind the huge, boxy head, which makes up a quarter to a third of the body. Its single blowhole sits at the front left of the head, so the bushy blow shoots forward and to the left at about 45°. Instead of a tall fin it has a low, rounded hump followed by a row of bumps, and it lifts a broad triangular tail before a deep dive.

Biology

Sperm whales live in deep water in every ocean, and the Gulf of California holds a semi-resident population made up mostly of females, juveniles and calves; adult males range much more widely. Records span from San Felipe in the north to Los Frailes in the south, and the whales have been seen most often between Loreto and Isla Cerralvo. Photo-ID and mark-recapture work estimated about 1,070 animals using the gulf between La Paz and San Pedro Mártir. Their main prey there is the jumbo (Humboldt) squid: in 1999, when squid were plentiful, they gathered in three “super-aggregations” about 55 × 75 km across that held for over a month.

Females and their young live in stable social units of about a dozen animals; young males leave to form bachelor groups, and the largest males often travel alone. A calf is born about 4 m long after a 14 to 16-month pregnancy, and sperm whales can live about 60 years. The head holds the spermaceti organ, with up to 1,900 liters of a waxy oil that helps focus the clicks they use to find prey in total darkness. Whales tagged near Santa Rosalía made most of their deep dives to 100–500 m, the same layer where the squid live, with a few dives to 1,250–1,500 m.

Things you probably didn't know

The loudest animal on Earth

Sperm whale clicks recorded off Norway reached 236 dB re 1 µPa. The researchers called them by far the loudest sound measured from any living source.

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A 9 kg brain

The sperm whale has the heaviest brain of any animal, about 9 kg, six times heavier than a human brain, yet only about 0.02% of its body weight.

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From the Galápagos to the Sea of Cortez

Photo-ID showed seven female sperm whales that moved from the Galápagos Islands into the Gulf of California, traveling up to 3,803 km, among the longest movements documented for females.

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They left when the squid left

In the Midriff Islands region, researchers logged 73 sightings totaling 648 sperm whales from 2009 to 2015. Squid landings fell from about 26,900 tons to under 200, and from 2016 to 2018 not a single sperm whale was seen there.

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Diving to the squid layer

In the Guaymas Basin, the depth of sperm whale dives tracked the depth of the sonar “scattering layer” where prey gathers, and whales surfaced 10 times with jumbo squid in their mouths.

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Clans with their own accents

An analysis of 23,429 click patterns (codas) recorded across the Pacific from 1978 to 2017 identified at least seven clans, each with its own identity codas, used most distinctly where clans overlap.

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Photos

Sperm whale, photo 1 (Azores, PT) — Daniel Benák · iNaturalist · CC BY 4.0

Sperm whale, photo 2 (Guaymas, MX-SO) — Julian Pietragalla · iNaturalist · CC BY 4.0

Sperm whale, photo 3 — harum.koh · iNaturalist · CC BY-SA 4.0

Sperm whale, photo 4 — Charlotte Kirchner · iNaturalist · CC BY 4.0

Sperm whale, photo 5 — Sue Carnahan · iNaturalist · CC BY 4.0

Seeing them from the boat

Near Los Cabos, sperm whales are an occasional, offshore sighting rather than a regular show like the winter humpbacks; local whale-watching operators list them among the species you might see. No monthly pattern has been documented off Cabo. In March 2016 a juvenile about 10 m long stranded near San José del Cabo and was guided back to deep water by PROFEPA and the Navy. The best-studied area is the central Gulf, around Santa Rosalía and the Guaymas Basin, although they have been scarce in the Midriff Islands since the jumbo squid collapse.

If you run into one offshore, slow down, stay at least 60–80 m away and never cut in front of a whale that is about to dive. Under Mexican rules you can’t fish, swim or dive while watching whales, and the sperm whale is the only toothed whale that legally counts as a “whale” for those rules.

Rules & conservation

Closest approach (NOM-131)	60 m for boats under 10 m, 80 m for boats 10 m and larger; 240 m waiting distance for all other boats. NOM-131 defines “whales” as all baleen whales plus the sperm whale
Boats per whale or group	4 at most, for 30 minutes at most
Speed near whales	Under 5 knots, under 2 knots inside the watching zone
Not allowed	Fishing, swimming, diving, getting between mother and calf
Mexico (NOM-059)	Subject to special protection (Pr)
Ley General de Vida Silvestre, art. 60 Bis	No extractive use or possession of any marine mammal, except authorized research and conservation
IUCN Red List	Vulnerable (reassessed 2025)

It’s often called the deepest-diving whale, but the record belongs to Cuvier’s beaked whale, tagged at 2,992 m off California.

Don't confuse it with

Dwarf and pygmy sperm whales share the name but are under 4 m and rarely seen at the surface. A gray whale also has a hump and knuckles instead of a fin, but it is mottled gray and white and blows straight up, not forward and to the left.

Questions

Can you see sperm whales in Cabo San Lucas?

Occasionally, well offshore, but there is no reliable season off Cabo. They are much more regular in the deep basins of the central Gulf of California.

Do sperm whales eat Humboldt squid?

Yes. In the Gulf of California the jumbo (Humboldt) squid is their main prey, and when the squid fishery collapsed in the Midriff Islands region, the sperm whales disappeared from it.