The terms malnutrition and starvation are used interchangeably, when in reality, there are specific definitions for each. Malnutrition is the inadequate intake of any of the required nutrients. This can even occur in an animal receiving large amounts of food, but is not able to ingest, digest, absorb, or utilize this food. Causes for this inability are injuries, poor teeth, parasitism, disease, foreign bodies in the digestive tract, tumors, or an increased motility of the digestive tract.
Malnutrition can also occur if the food is inadequate in one or more of the required nutrients.
If an animal is not able to obtain food for an extended period of time either for the above reasons or due to an unavailability of food or insufficient energy intake, this is defined as starvation. Malnutrition and starvation can be caused by diseases, injuries, the range the animal lives on, or the environmental conditions it must live in. Starvation and malnutrition occur in several wildlife species and routinely eliminates the young, old, weak, and sick animals. Winter is when mortality usually occurs due to the negative energy balance brought about by the cold weather, deep snow, increased energy demands, snow covered food, and human and predator induced stress. Historically, in Michigan the number of species diagnosed at the Laboratory as dying from malnutrition and starvation are second only to those dying from traumatic injuries.