The rabbit is a small mammal that is unique in that it can extract additional nutritional value from its food by fermenting the fiber it ingests. Rabbits do not practice coprophagy (the eating of feces) but rather ceacotrophy which is the re-ingestion of caecotropes or fermented fiber also known as soft pellets.
Rabbits live in a diverse array of habitats and have long ears and large powerful hind legs that aid in their ability to hear and run from predators.
The male rabbit is called a Buck, the female rabbit is called a Doe and baby rabbits are called kits. The breeding of domestic rabbits have diversified them into a large range of sizes (from 2 pounds to 30 pounds) and colors.
Rabbit Digestion and Health
The rabbit digestive system is designed to primarily process hay. Too much starch from grain or sugar from fruit can alter the balance of bacteria that grow in the caecum where the hay is fermented which leads to diarrhea. This fermentation process creates short-chain volatile fatty acids that are absorbed directly across the caecal wall and into the blood stream. These fatty acids are a main source of energy for the rabbit and they also serve as building blocks for many biological macromolecules.
During the fermentation process bacteria can absorb urea from the rabbits blood stream and convert the nitrogen into protein that rabbits can later digest after eating the ceacotroph. These same bacteria also produce B-vitamins and other nutrients that the rabbit can absorb after re-ingestion of the caecotroph.
The Breeding and Life Cycle of Rabbits
Although rabbits can breed year around they naturally "hard-wired" to breed in the spring time. The lengthening of the day and the increasing availability of food stimulates the production of hormones that make rabbits fertile and receptive to breeding. In the wild rabbits generally wean their kits by three weeks of age to quickly start a second and final litter. The life-span of a rabbit in the wild is short because of nutritional deficiencies, predators, and exposure to the elements.
Domestic rabbits can be far healthier and live longer if they are fed high quality food that is enriched in nutrients that are normally limiting in the wild. For example, grass (and alfalfa) has a limited amount of the mineral phosphorous (well fertilized hay is never higher than 0.3% and over half of it is not bio-available). High quality rabbit food supplies at least 0.4% to 0.6% available phosphorous because it is needed for every cell membrane and other biological processes. Without higher levels of this nutrient (and many others) the long-term health of the rabbit is severely restricted. To support normal growth the rabbit will need to consume and process more food just to obtain these limiting nutrients even if there is plenty of protein and energy in the diet.
Domestic rabbits are still heavily influenced by the day length and are far more likely to have missed pregnancies and miscarriages in the winter months. Although in the wild rabbits often re-bred immediately after kindling (giving birth) concurrent pregnancy and lactation places extra nutritional strain that shortens the lifespan of rabbits.