C. Camelids Chew Cud
Just like you see on tv, it’s time for a cross-over event between Mad Scientist.Crazy Mom and Five Maples Farm. While reading about the llama stomach I realized just how neat chambered stomachs are and thought it would make a nice science topic for this blog.
Llamas are members of the camelid family which also includes camels and alpacas, along with their wild ancestors, guanacos and vicuña. Similar to goats, cows and sheep, camelids chew their cud (or ruminate). This is due to the unique biology of their stomachs: their stomachs are actually multi-chambered organs through which the food is progressively moved.
The chambered stomach
Cows have 4 stomachs. Remember this fact from when you were a kid? Although there aren’t truly 4 individual stomachs in the cow, the cow stomach has 4 separate compartments. This makes the cow and some other animals (goats and sheep) true ruminants: they have a 4-chambered stomach and chew their cud. All camelids however, have a 3-chambered stomach, so they are often referred to as pseudoruminants. Pseudo or not, they spend a good portion of their day ruminating: ~8 hours!
The chambered stomach is a unique adaptation for animals that subsist wholly on vegetable matter. Mammals don’t naturally break down cellulose, which is the building block of the plant cell wall. Therefore, their bodies require help and a little ingenuity to get the job done.
Fermentation – breaking down the walls
The first compartment of a llama stomach is called the rumen. It essentially acts as a fermentation vat, bringing together bacteria, liquid and plant matter. The bacteria are the key players in this compartment: they breakdown plant cell walls and convert the cellulose into digestible nutrients. However, not all the plant matter is broken down right away. Therefore, llamas regurgitate solid plant matter back into their mouths for another round of chewing and swallowing. A second, or even third trip is not sufficient to break everything down and the process will continue until there is no more cud. This long process can take up to 60 hours.
After passing through the rumen, the liquid portion moves into the second chamber called the omasum. Here some liquid, minerals and bacteria that entered from the rumen are absorbed in the blood stream.
Throw in some acid
Next, the food (if you can call it that) moves into the abomasum, which is probably the chamber that resembles the human stomach the most. Here food is digested chemically. The abomasum contains stomach acids that break up the matter into proteins which are then absorbed by the intestines.
Advantages of a chambered stomach
Chambered stomachs, with both fermentation and chemical breakdown of food, allow llamas to subsist on plant matter, a very abundant food source (and they don’t have to chase their food down before they eat it).
In addition, more nutrients are adsorbed from the food as it is held longer in the stomach. This means that llamas can survive on poorer food sources because their bodies will extract more from it than other animals. It also means that per pound of body weight, llamas require less food. Llamas are the kings of food utilization with a higher utilization rate than cattle. (I don’t even want to know how this compares to humans.)
And another result of the llama stomach – the ability to spit green! Let’s hope you don’t experience that!
Blogging my way from A to Z as part of the 2016 April A to Z Challenge. Come blog through the alphabet with me.
Photo courtesy of Pedro Plassen Lopes.