### The Intriguing Phenomenon of Amazon River Dolphins and Their Unique Urination Practices
Amazon river dolphins, often referred to as **botos**, rank among the most mysterious inhabitants of South America’s waterways. With their distinctive pink coloration and specialized adaptations for thriving in murky river environments, these dolphins have captivated both local legends and scientific inquiry for ages. Recently, researchers have identified an unusual behavior in male river dolphins: **aerial urination**, a occurrence that has left scientists both intrigued and perplexed.
—
#### **A Mythical Context**
In the lore of the Amazon, male river dolphins are thought to be *encantados* or shapeshifters, capable of becoming attractive young men who charm and impregnate women. Although this myth likely arises from the dolphins’ human-like physical traits, contemporary science has not validated any extraordinary abilities. Nevertheless, what researchers have noted is a behavior that appears just as bizarre: male dolphins rolling onto their backs, revealing their genitals, and projecting streams of urine as high as three feet into the air.
—
#### **The Breakthrough**
From 2014 to 2018, a group of Canadian scientists, led by Claryana Araújo-Wang from the CetAsia Research Group, carried out comprehensive land-based surveys of a dolphin community in Brazil’s Tocantins River. During 219 hours of monitoring, they recorded **36 instances of aerial urination**. These occurrences typically involved a single male dolphin (termed the “urinator”) alongside one or more other males (the “receivers”) who seemed intensely focused on the urine streams. In certain instances, the receivers even placed themselves directly beneath the streams, seemingly pursuing them with their snouts.
The researchers documented their discoveries in the journal *Behavioral Processes*, explaining that this behavior was entirely unforeseen. “We were genuinely astonished, as it was something we had never encountered before,” Araújo-Wang explained to *New Scientist*.
—
#### **What Could It Indicate?**
Although the precise reason for this behavior is yet to be determined, scientists have suggested several theories:
1. **Chemical Signaling**
Urine spraying is a widespread practice among many land animals, often employed to define territory, convey dominance, or indicate reproductive readiness. The researchers hypothesize that the male dolphins’ urine streams could contain chemical signals that relay information about their health, social ranking, or mating potential. While dolphins aren’t known for a keen sense of smell, they can perceive certain chemicals and secretions, such as urine and feces, through taste. Bottlenose dolphins, for example, use their tongues to recognize individuals by tasting their urine.
2. **Sound-Based Communication**
Another theory posits that the noise made by urine hitting the water might act as an acoustic signal. Dolphins are adept at picking up sounds, and the unique sounds created by a splashing urine stream might convey messages to nearby dolphins.
3. **Social Interaction**
This behavior may also function as a form of social display or compete among males. The researchers compared it to a “pissing contest,” a familiar term reflecting competitive actions among humans. The act of launching urine high into the air might be a method for males to assert power or draw attention.
4. **Inherent Enjoyment**
Lastly, it’s possible that the dolphins simply find amusement in the act of spraying urine and watching the resulting arcs. While this explanation is less scientific, it cannot be completely dismissed.
—
#### **Similar Behaviors in Other Species**
While aerial urination is uncommon in aquatic species, analogous behaviors can be found in others. For instance:
– **African Cichlids**: These freshwater fish discharge bursts of urine to mark their territory and signal reproductive status.
– **Crayfish**: Male crayfish utilize urine to express aggression and establish hierarchy, with the recognition of urine often decreasing conflict among individuals.
Evidence of urine being used for communication among cetaceans is sparse. Still, the researchers note that bottlenose dolphins have been documented using urine for individual recognition, indicating that chemical communication through waste isn’t entirely unheard of among aquatic mammals.
—
#### **The Larger Context**
The revelation of aerial urination in Amazon river dolphins adds complexity to our comprehension of these extraordinary animals. It emphasizes the need for ongoing observation and study of their behavior, particularly given environmental threats like habitat loss and pollution. The Tocantins River, like many rivers in the Amazon basin, faces challenges from human activity, making it increasingly essential to document and safeguard the distinctive behaviors and ecosystems of its residents.
—
#### **Final Thoughts**
While the specific rationale behind aerial urination in Amazon river dolphins remains elusive, this behavior highlights the intriguing and often unexpected variety of animal communication methods. Whether functioning as a chemical indicator, an acoustic signal, or merely a social exhibition, this unusual practice provides a captivating insight into the
