How Cormorants Swallow Huge Fish Without Choking

Have you ever been so hungry that you don’t even bother to chew? That kind of approach is an everyday thing for cormorants, a family of seabirds that dine exclusively on fish and swallow them whole. No matter the meal, these birds make quick work of it thanks to several unique anatomical features.

In this YouTube video, a cormorant grabs a fish practically the size of its own body and downs it in several swallows. It’s impressive and frankly, kind of intimidating. Let’s learn more about how seabirds like the cormorant manage this marvelous feat. But first, let’s get a bit of background on these hardy seabirds.

Cormorant Characteristics

The term ‘cormorant’ refers to more than 40 species of aquatic birds in the Phalacrocoracidae family. These birds, also known as shags, have been classified in various ways over the years, sometimes inconsistently. However, cormorants are generally medium-to-large seabirds, with wingspans of up to three feet and dark feathers. Cormorants also have long, thin, and hooked beaks. These features, along with the webbing between their four toes, help them catch fish with ease.

Shags and cormorants are skilled divers, capable of plunging as deep as 150 feet to catch fish. Some varieties, like imperial shags, have been recorded foraging on the sea floor. Their preference for fish and their remarkable hunting abilities have enabled these birds to spread across the world. Cormorants are found almost everywhere in the world, except for the central Pacific islands. They typically nest in sizable colonies along shorelines, islets, and cliffs.

All types of shags and cormorants eat fish, as well as eels and water snakes. They spot their prey from the air, dive underwater, and use their feet to propel themselves toward their target. Perhaps the most fascinating aspect of these birds is their ability to swallow fish whole. In this YouTube video, a cormorant grabs a fish and makes it disappear with several gulps. How does it manage such a feat?

Big Gulps

As seen in this YouTube video, a cormorant swallows an entire fish with ease. Birds like shags and cormorants can do this thanks to specialized anatomical features. For one, this method of eating requires a two-chambered stomach. The first chamber, called the Proventriculus, secretes digestive enzymes that begin breaking down food such as fish. These acidic enzymes are powerful; cormorant stomach acid is highly acidic and much stronger than that of humans.

From there, the partially digested fish is transferred to the cormorant’s second stomach chamber. Called the Gizzard or ventriculus, this chamber consists of a thin muscle layer that grinds up the fish further. The fish is then cycled back and forth between the chambers until it is fully digested and absorbed. In certain birds of prey, indigestible parts like skin and bones are compacted into a pellet within the ventriculus and then regurgitated.

Before any of this happens, however, cormorants use their forward-facing eyes to determine which end of the fish comes first. They avoid swallowing the fish’s tail first because this could cause its scales to get caught in their throat. Once they get the fish oriented correctly, these seabirds gulp it down. They accomplish this using the glottis, an opening in their throat that connects to their respiratory system. This adaptation helps cormorants push food into their esophagus without choking. Comorants will later regurgitate partially digested food to feed to their young. As this YouTube video shows, eating a fish whole is no sweat for seabirds like cormorants.

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