Whales are surrounded by water all their lives but have you ever wondered what they do about drinking? How do whales drink water?
They are mammals like you and me, and we need at least a couple of liters a day. So what do whales do about drinking water?
Do they drink directly from the ocean or find freshwater sources somewhere?
Maybe they’ve developed a different way of tracking down the water they need to stay hydrated?
Do Whales get Thirsty?
Whales live in saltwater and eat salty food, so you’d expect them to get thirsty from time to time, but that’s not the case.
Whales don’t need as much water as land mammals because they don’t get dehydrated by the sun.
In a watery world, whales lose less water than land mammals. While humans lose moisture every time they exhale, whales lose only a little.
Unlike humans, who have sweat glands through which they lose water, the whale is insulated with a thick layer of fat.
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The whale uses these processes to reduce water loss, so they require less hydration in the first place.
Whales can also use their own body fat to create metabolic water. As they can reabsorb that water, whales rarely get thirsty.
Food is the primary source of water for most marine mammals.
Like the beaked and pilot whales, Toothed whales survive on a diet of fish, which contain between “60 or 80 percent water.”
Even baleen whales, which eat nothing but krill and plankton, can extract metabolic water from their prey as it digests it.
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Whales are fairly selective eaters and seek out “food with a salt content similar to that of their own blood.”
They get more water and less salt into their systems, making the metabolic breakdown easier.
Whales use what water they do ingest very effectively and, in doing so, minimize their need to drink.
How do Whales Drink Water?
Whales appear to consume vast amounts of water, but very little of this is ingested. When a baleen whale feeds, it does so with its mouth wide open, allowing gallons of water to pour into its mouth.
An adult blue whale takes as much as 10,000 gallons of water into her mouth with every gulp, and yet drinks very little of it.
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Most of it is filtered out through the baleen plate that sifts out the 16 tons of food she eats per day.
Do Whales Drink Fresh Water?
Whales drink very little water. They get most of their drinking water from their food.
Some marine mammal species, like manatees and some pinnipeds, will drink fresh water when it’s available but most rely on their food intake for the greatest proportion of their water intake.
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Do whales Drink Salt Water?
Whales drink seawater just as most other marine animals and sea birds do. Although this is not their primary water source, it is one they can process effectively.
Many marine mammals drink seawater on occasion and each species has developed a different way of coping with the large quantities of salt.
Like the brown pelican, some have salt glands that enable them to excrete higher concentrations of salt.
Others, like the whale, have specialized kidneys called that enable them to drink seawater.
These reniculate kidneys have multiple lobes that increase their urine-concentrating efficiency.
Scientists believe that many marine animals have longer tubules in their kidneys that also facilitate this process.
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Tubules are tubular structures that filter important nutrients and body fluids back into the blood cells. The longer the tubules, the more efficient their urine-concentrating ability.
This process enables whales to utilize seawater much more efficiently than a human could.
There is no evidence that whales have a salt excreting gland even though many marine birds and reptiles “excrete the excess sodium chloride through a nasal salt gland.”
Researchers who tested the pilot whale’s tears said that they “do not appear to have high salt concentrations.
How do Whales get Water to Drink?
Whales get much of the water they need from their food intake, producing it internally during the metabolic breakdown of food.
Whales and other sea mammals produce metabolic water when processing fats and carbohydrates.
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As their metabolisms set to work, they break down their prey into nutrients that are further reduced into energy and water.
The water ingested from fat is greater than any other food source, and whales can even break down their own blubber to gain access to drinking water if necessary.
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What Happens When Whales Ingest Salt Water?
At the peak feeding time in Antarctica, a blue whale can swallow “as much as 150 percent of its body weight worth of water in one gulp.”
Very little of this water is ingested, with large quantities being removed by the whale’s effective filtration system.
The small amount of water ingested moves through a second filtration system in the kidneys. This removes larger molecules and prevents blood cells from entering the kidneys.
Once filtered, water and small molecules, including salts, pass through the loop of Henle.
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This long tube allows filtered water to be reabsorbed into the whale’s body while removing large quantities of salt.
As they can reclaim more water than land mammals, whales and other marine mammals don’t need to drink as much.
They also produce more concentrated urine, and milk when lactating.
How do Whales Drink Milk Underwater?
For the first five to seven months of their lives, whale calves rely on their mothers for food. Then, as they are mammals, whales produce milk for their young.
However, unlike humans, whales don’t have lips with which to suckle. Instead, the mother must squirt the milk into the mouth of her hungry baby.
Because of the complexities of feeding underwater, and presumably to further minimize their need to drink, whale’s milk contains much less water than the milk of land mammals.
Whale milk has a “toothpaste-like consistency,” that enables the mother to shoot it into her baby’s mouth.
If it was more watery, it would dissolve in the seawater before the baby had a chance to swallow it. How a calf accesses its mother’s milk remains a mystery.
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However, national Geographic Explorer and marine ecologist Leigh Torres believes it involves a “combination of the mother flexing her abdominal muscles to expose the nipple and then squirting the milk into her baby’s mouth.”
To make things even more difficult, whales hide their nipples beneath folds of skin to make themselves more aerodynamic.
Drinking seawater is the only way whales maintain their water balance. They have powerful kidneys that can effectively filter salt water and make it available for reabsorption.
Whales produce much of the water they need during their metabolic processes and can even use their own blubber to produce water when necessary.
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By reducing the amount of water they need, whales also minimize how much they need to drink.
These complex processes enable the whale to survive on the water it receives from its food, and the seawater it ingests while feeding.
Nicky is a British adventurer and animal lover who spends her time exploring the natural world and writing about her experiences. Whether on horseback, underwater, running, hiking or just standing with a fishing rod in hand, she embraces everything her adopted home of South Africa has to offer.