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How many compartments are in a cetacean stomach?

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Illustration showing various cetaceans, including baleen whales like the blue whale, fin whale, humpback whale, gray whale, sei whale, northern right whale, and bowhead whale, as well as toothed whales such as the sperm whale, narwhal, beluga, Baird's beaked whale, killer whale, dolphins, and porpoises. Each species is labeled with its scientific name and typical or maximum length, with a size scale in the corner for reference. — cetacean Whales (order Cetacea).

The stomach of a cetacean is composed of four compartments: the forestomach, the main stomach, the connecting chambers, and the pyloric stomach.1

It is important to note that the forestomach is not a true stomach; it is a dilation of the esophagus that functions as a holding chamber. The main stomach, which is lined with active gastric epithelium, serves as the first true digestive compartment. From there, food passes through the connecting chambers and the pyloric stomach before entering the small intestine.1