The rabbit, as an herbivore, is uniquely designed to consume large amounts of plant material.
The plants that rabbits eat are high in fiber, which is indigestible to mammalian digestive enzymes.
This means that humans and many other animals cannot utilize the nutrients found in these plants.
However, the rabbit’s digestive system makes it able to consume these plants and make the most of their nutrients.
How the Rabbit Digestive System Works?
The initial stages of rabbit digestion are the same as most mammals. When a rabbit eats, the food travels from the mouth, down the oesophagus, into the stomach, and onto the small intestine.
The small intestine is responsible for absorbing the nutrients from food. As food travels along it, enzymes break the food down into individual nutrients that are small enough to pass through the lining of the intestine and be absorbed into the bloodstream.
Enzymes can’t break down fibre, so in most mammals, the fibre portion of the food would travel on through the colon and is excreted as waste. However, in rabbits, the colon sorts the fibre into two types, digestible and indigestible.
Digestible fibre has nutrients locked away inside it, so the colon diverts it to the caecum for processing. The leftover indigestible fibre doesn’t contain any useable nutrients, but it is still essential to the digestive process, as it has helped carry the food through the digestive system.
Its job is now complete, so the colon forms it into the hard round droppings your rabbit leaves in his litter tray and it passes out of the body as waste.
Meanwhile, in the caecum, a colony of special bacteria ferments the digestible fibre, breaking it down to release the stored nutrients.
The caecum can absorb some of the nutrients but most need to go back through the small intestine to be absorbed. To achieve this, the fermented fibre moves back into the colon, where it is coated in protective mucus, before being excreted from the body as special droppings, called cecotropes or cecal droppings.
The rabbit eats these droppings (a process called cacography) so they pass through the digestive tract again. In their new format, the small intestine can easily absorb nutrients.
Why the right diet is important?
Having such a specialized digestion system has drawbacks. Whilst it’s very efficient at processing high fibre – low nutrient food like grass, the wrong types of food or sudden diet changes can easily disrupt it throwing the whole digestive system out of balance. For example:
- Too little bulky hay or grass to help food move along the gut slows it down and stops food from traveling at the optimum speed for the digestive process to work.
- Too much carbohydrate or protein can send the gut into overdrive and produce sticky unformed droppings.
