Respiration in Rabbits
The normal respiratory rate for an adult rabbit ranges from 30 to 60 breaths per minute. However, certain rabbits may exhibit faster breathing patterns in response to elevated temperatures or stress.
Labored or prolonged breaths, accompanied by wheezing, can be alarming. If the rabbit’s lips or tongue appear blue, this could indicate insufficient oxygen intake. A clear sign of breathing difficulty is when a rabbit remains still with its head slightly elevated.
Mechanism of Rabbit Respiration
Breathing involves the intake of fresh air into the lungs, known as inhalation, and the expulsion of air from the lungs, referred to as exhalation. This process can be detailed as follows:
Inhalation
Inhalation is an active process that draws fresh air into the lungs. This occurs through the contraction of the external intercostal muscles, which pull the ribs and sternum forward and downward. Simultaneously, the diaphragm’s radial muscles contract, flattening the diaphragm and increasing the internal volume of the thoracic cavity, thereby reducing the pressure within that space.
This reduction in pressure causes the lungs to expand, enabling air to rush in due to the greater atmospheric pressure outside. The inhalation process follows several steps:
- Air enters through the external nares.
- It passes through the nasal passages.
- It moves into the internal airways.
- Then it reaches the larynx.
- Next, the trachea.
- Followed by the bronchi.
- Then the bronchioles.
- Finally, arriving at the alveoli in the lungs.
The external air continues to flow in until the air pressure within the lungs equals the atmospheric pressure. Hence, inhalation occurs through two primary movements:
- Flattening or lowering of the diaphragm.
- Forward movement of the ribs and sternum. This is how inhalation takes place.
Exhalation
Exhalation is the reverse of inhalation. During this process, the internal intercostal muscles, located at a right angle to the external intercostal muscles, contract while other muscles relax, returning the ribs and sternum to their resting position.
Simultaneously, the diaphragm relaxes to its original position. This reduction in thoracic cavity volume generates significant pressure within the lungs, causing the elastic lung walls to contract and push expelled air out through the same pathway as mentioned above.
Why Do Rabbits Breathe Through Their Noses?
Rabbits primarily respire through their noses due to the unique positioning of their epiglottis, which is located at the back of the soft palate, the rear section of the mouth’s roof. The epiglottis functions to prevent food from entering the airways, effectively separating the soft palate from the hard palate during breathing while eating.
Additionally, there is a layer of tissue above the opening of the epiglottis within the mouth that obstructs air flow from the mouth to the trachea. Consequently, any air drawn in through the mouth does not effectively reach the lungs.
Respiratory Issues in Rabbits
The severity of respiratory problems in rabbits can be attributed to the following factors:
- Rabbits are incapable of breathing through their mouths, meaning that nasal congestion can make breathing extremely difficult.
- As prey animals, rabbits instinctively conceal any signs of illness to protect themselves, often resulting in respiratory issues going unnoticed until they become more severe.