Camels are often associated with a peculiar behavior: appearing to spit out their stomach. This common belief, however, is a misconception. While camels do expel a foul-smelling substance from their mouths, it is not their stomach, but rather a part of their digestive process or a specific anatomical display. This behavior is a fascinating adaptation that serves various purposes in their daily lives.
Unpacking the Myth: What Camels Really Expel
Instead, they regurgitate partially digested food, commonly known as “cud,” mixed with saliva and digestive fluids. This expelled material is typically greenish and has a strong, unpleasant odor. The act is more akin to vomiting or projectile regurgitation than traditional spitting.
Sometimes, this expulsion is accompanied by a balloon-like sac protruding from the camel’s mouth. This “bubble” is not an internal organ but rather an inflatable extension of the soft palate, often referred to as a “dulla” or “palatal flap,” especially prominent in male camels. The sight and smell of this regurgitated cud and inflated dulla are designed to be highly off-putting.
Why Camels Engage in This Behavior
This unique behavior primarily serves as a defensive mechanism. When a camel feels threatened, agitated, or stressed, it may regurgitate its stomach contents as a deterrent. The nasty, slimy, and stinky nature of the expelled cud, along with its appearance, is intended to surprise, distract, and warn off potential threats, whether predators, rival camels, or even bothersome humans.
Beyond defense, camels also use this behavior in social contexts. Male camels, especially during breeding season, may inflate their dulla and regurgitate cud to assert dominance over other males. This display helps establish hierarchy within the herd and can attract mates by showcasing their strength.
The Anatomy Behind the Display
The ability to regurgitate cud is linked to the camel’s digestive system. Like other camelids (such as llamas and alpacas) and ruminants (like cows), camels possess a multi-compartmented stomach. While true ruminants have four stomach compartments, camels have three, which allows them to efficiently break down tough plant fibers by regurgitating and re-chewing their food. This process, known as rumination, involves moving partially digested food from the first compartment back to the mouth for re-chewing.
The visible “bubble” often seen during this behavior is the palatal flap or dulla, a soft, fleshy structure in the roof of the camel’s mouth. In male camels, this structure can be inflated by pushing air from the lungs into it, causing it to protrude from the mouth. This inflation makes the display more visually impressive and intimidating, further enhancing its role in defense and social signaling.