The sight of a massive spout erupting from the ocean’s surface is often the first indication that a whale has arrived. This dramatic plume, which can rise dozens of feet into the air, is the most visible sign of a cetacean surfacing after a deep dive. Observers have long been captivated by this display, leading to the common misconception that the animal is actively blowing water. Understanding this powerful action provides insight into the specialized physiology of these mammals.
The Proper Terminology
The action of a whale forcefully expelling air when it reaches the surface is called the “blow” or the “spout.” Marine biologists universally use these terms to describe the visible mist or spray, and the verb used to describe the activity is “spouting.”
The term “blow” focuses on the forceful exhalation of air from the lungs. Conversely, “spout” refers to the resulting visual effect—the cloud of mist visible from a great distance. Both terms are accurate and widely used when discussing the whale’s respiratory cycle.
What the Spout Really Is
Contrary to popular belief, the visible plume is not a blast of water expelled from the whale’s lungs. The spout is primarily composed of superheated, exhaled air from the whale’s respiratory system. This air is warm, reaching approximately 98.6°F (37°C), and is saturated with water vapor.
When this warm, compressed air rapidly expands and meets the much cooler atmosphere above the ocean, the water vapor quickly condenses. This instantaneous condensation creates a cloud of fine water droplets, similar to the fog produced when a person exhales on a cold day. The plume also contains a cocktail of biological matter, including oils, mucus, and metabolic waste from the respiratory tract.
The exhalation is often accompanied by seawater resting on the whale’s head around the blowhole, which is cleared away by the force of the breath. Scientists have also detected microbial species in the spouts, providing valuable information about the whale’s respiratory health.
The Mechanism of Breathing
Whales, like all marine mammals, are conscious breathers, meaning they must actively choose to initiate each breath. When a whale surfaces, it must execute a rapid and powerful respiratory cycle using a specialized opening on the top of its head called the blowhole, which is homologous to the nostrils of other mammals. The blowhole is sealed by muscular flaps when the whale is submerged, preventing water from entering the lungs.
The breathing process is extraordinarily efficient and fast, often taking only one to two seconds for large whales to complete. This cycle involves an explosive exhalation, the blow, followed immediately by a massive, deep inhalation. Whales are capable of exchanging up to 90% of the air in their lungs with each breath, a vast improvement over the 10 to 15% exchange rate typical for humans.
The air is expelled at tremendous speed, with measurements in a young gray whale suggesting speeds up to 450 miles per hour (720 km/h). This forceful expulsion is necessary to quickly ventilate the lungs before the whale submerges again for another dive. The high pressure and volume of the air leaving the lungs is what causes the visible spout to shoot upward with such power.
Variations Among Whale Species
The shape and height of the blow are distinguishing features that marine observers often use to identify a whale species from a distance. Baleen whales (Mysticetes) typically have two blowholes, which are widely spaced, leading to characteristic spout shapes. The North Atlantic Right Whale, for instance, produces a distinctive V-shaped blow, created by the simultaneous exhalation from its two separate blowholes.
In contrast, toothed whales (Odontocetes) generally possess a single blowhole, resulting in a single, less pronounced column or bushy blow. The Blue Whale, the largest animal on Earth, creates a tall, narrow column that can reach 20 to 30 feet (6 to 9 meters) in height due to the sheer size of its lungs. The Sperm Whale’s blow is unique, appearing low and angled forward because its single blowhole is offset to the left side of its head.