Let’s start by clarifying that tuna is not your ordinary fish. Tuna is a pelagic marine fish that exhibits variations in color and size across different species. Taxonomically speaking, tunas are predatory fish belonging to the “tribe” Thunnini, which is a subgroup of the mackerel family (Scombridae). The tribe comprises eight “true tunas” from the genus Thunnus (including white, red, tongol, yellowfin, blackfin, and three species of bluefin), as well as seven other tuna species like skipjack, sand eel, and little tunny.

All tunas, from the small bullet and Melva species to the gigantic bluefin tuna, possess hydrodynamic bodies with a fusiform shape and a crescent-shaped caudal fin. They also feature two dorsal fins, pectoral fins that can be folded for streamlined swimming, and triangular “aletitas” along the upper and lower sides of the tail.

While the skin coloration varies among species, it generally transitions from a metallic blue on the upper part to a silvery white below, often adorned with yellow accents.

Observing a tuna, one can witness one of the most awe-inspiring examples of biological machinery in the entire ocean.

“When you look at a tuna, you see an animal that has been designed for exceptional performance,” stated Randy Kochevar, a marine biologist collaborating with Block at Stanford University’s Hopkins Marine Station.

Indeed, every aspect of tuna physiology seems to surpass the limits of what is physically possible. From highly efficient gills to a large heart capable of beating up to 200 times per minute, these animals exhibit incredible adaptations that have been refined over hundreds of millions of years to achieve remarkable performance. They are highly active and voracious fish, highly valued for their meat as a culinary delicacy. Tuna represents a marvel of nature, embodying pure power, speed, and endurance. They can withstand extreme cold, dive to great depths, and swim at speeds approaching 80 kilometers (50 miles) per hour. Larger species can reach astonishing dimensions, sometimes exceeding 3 meters (10 feet) in length. The world-record Atlantic bluefin tuna, caught in Nova Scotia in 1979, weighed 678 kg (1,496 lbs) and holds the top spot as the largest fish ever caught.

“They are at the pinnacle of bony fish evolution, the ‘super fish,'” described Barbara Block, a renowned marine biologist at Stanford University specializing in yellowfin tuna.

Throughout their careers, Block and her team have tagged and tracked over 2,000 bluefin tuna from the Atlantic and Pacific oceans. Their research has unveiled valuable insights into the epic migrations undertaken by these extraordinary fish. For instance, they documented a Pacific bluefin tuna that swam from California to Japan and back (a distance of over 16,000 km or 10,000 miles) within a mere five-month period in 2003.

Similar to lions and wolves, tunas rank among the top predators that undertake extensive journeys in search of prey. They tend to hunt in groups (schools) and play a crucial role in regulating the ocean’s food chain. While it may seem unusual to compare the primary components of Fancy Feast with these iconic land mammals, the comparison is more fitting than one might imagine.