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[Faculty Essay] Life Without a Gallbladder

  • February 17, 2009
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By Professor Shin Nam-sik, College of Veterinary Medicine

Are those animals that lack a gallbladder sillier than those that have one?

When a person acts eccentric or says silly things, Koreans say he lacks a gallbladder. When someone is brave, bold and daring, we say he has a big gallbladder. Older Koreans used to say that deer get startled easily and always seem nervous and on edge because they have no gallbladder.

The gallbladder is an organ that stores bile, which neutralizes acids, and in fact, deer do lack this organ.

Bile, which is stored in the gallbladder, is secreted from the liver and flows into the duodenum. Bile acids help emulsify fats and stimulate the effect of lipase, which is secreted from the pancreas. Bile acids also dissolve fatty acids to make them easier to absorb when they reach the intestine. Because bile acids play essential roles in the digestive process, all vertebrates must have them.

While it is not scientifically proven why some animals have gallbladder and some don’t, it is understood that the presence of the gallbladder is related to the interval of food intake. Animals like felines and canines, which take in food in intervals, require a large amount of bile acid at once, so a gallbladder is developed in their anatomy.

However, animals that eat frequently, without long intervals, constantly need bile acids, so an organ to store the acids is unnecessary.

All members of the deer family except for the musk deer, all of the equine family (including zebras), camels, giraffes, elephants, rhinoceroses, whales, some birds (such as doves), rats and some fish do not have gallbladders.

So are those animals that lack a gallbladder sillier and more incompetent than those with one?

When deer get startled and run away, they look around nervously, not because they forget what they were running from, but to find a safe place to go after putting some distance between them and the predator.

Zebras have to be vigilant when they gather in a group to rest or eat, so they look in all different directions, carefully checking their surroundings for predators. Because they have to run when they are in danger, zebras rarely sleep comfortably.

Elephants are the most prudent, thoughtful animal of all. In order to maintain their gigantic body, they have to eat about 250 kilograms of grass every day. They spend two-thirds of the day looking for food, so they hardly have any time to sleep.

Camels live in barren deserts, so they have to search for food all the time. They are incredibly adaptive and persevering, capable of walking over 10 hours a day, covering more than 50 kilometers with a load of 250 kilograms on their back in the heat of the desert.

Over five meters tall, giraffes can see predators from afar and alert other animals to danger. By eating leaves on the tall trees, these gentle creatures avoid competing with other animals for food.

Whales are mammals, but they never get to go ashore. They are constantly on the move in the vast oceans. In order to find food, whales wisely cooperate with one another as a group.

Rats are always busy, and doves and other birds start their day very early.

These animals with no gallbladder cannot afford to enjoy leisure time like some other animals. They are diligent, wise, quick and patient. Because they have to be prepared for attacks and keep a sharp lookout all the time, they’re hardly ever at ease.

All animals have their own way of living. However, the diligent creatures’ dynamic lifestyle is more appealing than the idle lives of leisurely animals.

So having a big gallbladder might not be such a compliment after all. It might mean that you eat too much fatty food. If you did, you’d need large amounts of bile acid in order to digest your meals, so you’d need a big gallbladder.

Feb. 17, 2009
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