Kangaroos are herbivores, meaning that they rely solely on plants for their nutritional needs. When selecting plants to eat, they generally choose grasses, plants, and shrubbery with high water content. This species generally forages for food at night when the temperatures are much cooler to avoid the sweltering daylight sun. By moving at night, it is easier for the kangaroo to conserve valuable energy and water. Red Kangaroos have a digestive system that is highly specific to their diet. It is similar to those of sheep and North American deer. Kangaroo's teeth are specialized for chewing tough plants and grasses. They have front incisors that cut the food and back molars that help grind it into a paste. By eating tough vegetation, kangaroo teeth get worn down over time. Unlike placental mammals that usually lose and then grow new ones to replace them, teeth in kangaroos move forward and are shed out of the mouth. Eventually, the kangaroo is left with only its back molars. After the food is chewed and swallowed it is carried down the esophagus into the gut. It is in the expanded foregut where bacteria, fungi, and protozoa are able to ferment food that the animal is unable to do with its own digestive enzymes. Because there is no oxygen in this portion of the gut, all energy from the food can be conserved. This also enable the microorganisms to utilize only a small amount of the energy from the food, therefore leaving the rest for the kangaroo. This mutualistic relationship has allowed the kangaroo to survive by eating vegetation that does not provide a great deal of energy. When digestion is finished, the kangaroo usually gains about 70% of the energy ingested, which is considerably higher than other herbivores, but still lower than most carnivores. Nutrients are then carried in the blood throughout its closed circulatory system to provide nutrition to the systemic tissues of the body. If extra energy is consumed, it is stored in tissues of the body.
*Interestingly, Kangaroos can survive by drinking water only twice a week. It is able to do this because of its efficiency in utilizing water found in the foliage it eats each day. During the cooler months of the year Kangaroos can survive solely on the vegetation it feeds on for its water needs. Not only is this species extremely efficient in its lifestyle and water consumption, it also has the ability to excrete salts that are concentrated in the urine to decrease its water loss. Also, by reabsorbing urea, the waste product in urine, the body can reuse this substance and ultimately help conserve water. The elongated structure of a Kangaroo's large intestine and rectum also function to produce a dry feces, insinuating further water reabsorption in the last stages of digestion.
*Interestingly, Kangaroos can survive by drinking water only twice a week. It is able to do this because of its efficiency in utilizing water found in the foliage it eats each day. During the cooler months of the year Kangaroos can survive solely on the vegetation it feeds on for its water needs. Not only is this species extremely efficient in its lifestyle and water consumption, it also has the ability to excrete salts that are concentrated in the urine to decrease its water loss. Also, by reabsorbing urea, the waste product in urine, the body can reuse this substance and ultimately help conserve water. The elongated structure of a Kangaroo's large intestine and rectum also function to produce a dry feces, insinuating further water reabsorption in the last stages of digestion.