How Do Sharks Pee and Poop?

February 14, 2024

Sharks are fascinating creatures that evoke feelings of fear, awe, curiosity and respect. They have been depicted in popular culture as ruthless predators, but these unique animals are complex and many species are docile. As part of their natural process, sharks eliminate waste products from their bodies through urination. Let’s explore how do sharks pee and poop, and what other unique functions this process serves.

Shark Urination

Like most fish and animals, sharks do not have a urinary bladder, instead they continuously urinate through their skin. This process is called ureotelism, and it allows them to maintain a concentration of urea in their body tissue and prevent dehydration. Moreover, it helps them conserve energy when they are not eating.

While the exact chemical composition of shark urine is still unknown, scientists have discovered that it consists of nitrogenous waste, glucose and creatine kinase. Nitrogenous waste is derived from protein breakdown and the metabolism of fats, while glucose is produced in the liver, muscle cells and in the kidneys. Creatine kinase is an enzyme that helps in breaking down fatty acids, and it is mainly found in the heart and skeletal muscles.

Sharks release their urine into the ocean through a gland near the anus, and this is how they remove excess salt from their bodies. This is crucial, especially for apex predators that are constantly moving around the water column in search of prey. They also use urination to communicate with other sharks in their habitat, and this function is enabled by the ammonium chloride that is released during this process.


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