Excretory System
In this section we tackle the unsavory yet vital aspect of blue whale survival, their excretory system. We will look at both how they digest their food and expel the resultant waste from food and drink.
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The Stomach
The First step in the blue whales digestion system is the stomach which has some unique features.
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The stomach of a blue whale is actually three different chambers. The fore stomach, main stomach, and the pyloric stomach .
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The fore stomach, while technically still a stomach, has no digestive processes going on in it. It rather acts similar to a birds crop, where it hold the food before transferring it to the main stomach for the first step in digestion.
The main stomach contains most of the digestion chemicals such as pepsin and hydrochloric acid and can hold upwards of 1000 kilo grams of food to be digested before passing it to the final stomach.
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The pyloric stomach has the final stage of stomach digestion and also has a small amount of hydrochloric acid to digest the contents right before passing the contents to the intestines.
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Kidneys
Like all other mammals blue whales also have a pair of kidneys that filter out waster like excess salt from blood, but due to the increased salinity of the blue whales environment their kidneys are highly specialized to filter out salt at a more concentrated rate.
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While blue whales do get most of their water from their food source they still need to have kidneys that filter out large amounts of water to keep chemical balance. This is due to the fact that they oxidize fats ate a greater rate then proteins or carbs so they lose a lot more water then if they didn't process fats so heavily.
Unlike a lot of mammals however the kidneys are actually connected to the uterus which then leads to the bladder and then the urethrae for the expulsion of the waste filtered by the kidneys.
