Adult Fin Whale (Balaenoptera physalus) surfacing in the lower Gulf of California (Sea of Cortez), Mexico.

Sperm Whale, Physeter macrocephalus, half breaching in the Midriff region of the Gulf of California, Mexico t

Sperm Whale (Physeter macrocephalus) shed skin held by CT in the Northern Gulf of California, Mexico

Sperm Whale, Physeter macrocephalus, calf, left unattended by adults, Gulf of California, Mexico

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

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.

Fin Whale (Balaenoptera physalus) Adult surfacing in the lower Gulf of California (Sea of Cortez), Mexico.

Sperm Whale (Physeter macrocephalus) surfacing (note blowhole detail, left side and forward on head. This is the species field diagnostic in the mid-riff region of the Gulf of California (Sea of Cortez), Mexico.

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.

Sperm Whale (Physeter macrocephalus) Assorted teeth from lower jaws of beached Sperm Whales in the mid-riff region of the Gulf of California (Sea of Cortez), Mexico.

Krill captured in a bottle! Taken from the site where a Fin Whale (Balaenoptera physalus) was surface feeding in the upper Gulf of California (Sea of Cortez), Mexico.

Adult Spinetail Mobula (Mobula japanica) leaping out of the water in the upper Gulf of California (Sea of Cortez), Mexico. Note the long whip-like tail (longer than the length of the body) with sting at the base - a unique field diagnostic to this species

Adult Sperm Whale (Physeter macrocephalus) surfacing in the upper Gulf of California (Sea of Cortez), Mexico.