Sperm Whale (Physeter macrocephalus) Eight-inch tooth from lower right mandible (jawbone) of an adult bull in the mid-riff region of the Gulf of California (Sea of Cortez), Mexico.

False-killer whale (Pseudorca crassidens) surfacing near Zodiac off Isla San Esteban in the midriff region of the Gulf of California (Sea of Cortez), Mexico. This animal is a member of the blackfish group, commonly called a whale, but in the family Delphi

False-killer whale (Pseudorca crassidens) surfacing off Isla San Esteban in the midriff region of the Gulf of California (Sea of Cortez), Mexico. This animal is a member of the blackfish group, commonly called a whale, but in the family Delphinidae (dolph

Adult fin whale (Balaenoptera physalus) surfacing in the calm waters off Isla San Esteban in the midriff region of the Gulf of California (Sea of Cortez), Baja California, Mexico. There are an estimated 400 resident fin whales residing in the Gulf of Cali

Sperm Whale (Physeter macrocephalus) fluke-up dive at sunset. Mid-riff region of the Gulf of California (Sea of Cortez), Mexico. (rr)

Sperm Whale (Physeter macrocephalus) Woman measures (98) the lower right mandible (jawbone) of an adult bull Sperm Whale, in the mid-riff region of the Gulf of California (Sea of Cortez), Mexico. Model released.

Young sperm whale (Physeter macrocephalus) surfacing in the midriff region of the Gulf of California (Sea of Cortez), Baja California, Mexico.