A humboldt squid (Dosidicus gigas) -- also known as the jumbo squid -- releases a cloud of ink at night in Mexico's Sea of Cortez. These large, carnivorous squids can reach more than 5 feet in length and travel in shoals of 1,000 squids. Although they have historically been found in the Pacific off the coast of Mexico, warmer and more oxygen-poor waters caused by global warming have allowed them to expand their range northward up the western coast of the United States.