The return of solids or fluids from the stomach to the mouth is usually referred to as regurgitation and may occur for a number of reasons. It is often differentiated from vomiting which is also described as an ejection of gastric contents through the mouth. Vomiting is usually thought of as a reflex activity, often a result of illness, toxins, diseases of the stomach and/or intestinal tract, drugs, and obstruction, among other possible causes.

Regurgitation is often voluntary, though it is difficult to totally divide these two actions into separate categories. Regurgitation may be the result of behavioral abnormalities and may be seen as part of a regurgitation reingestion complex seen in juvenile or adult individuals of other species.

Juvenile onset regurgitation may be seen in young cetaceans related to boredom, illness, decease in a previous level of interaction, social instability, lack of adaption to training techniques, misinterpreting fish as a play item, etc. Some individuals may exhibit this behavior for short periods with self-termination while others may progress in frequency, duration, and severity to the exclusion of normal activity. A medical workup should be performed when the behavior is persistent, interfering with daily activity, or if the animal shows signs of deterioration such as depression, weight loss, or isolation behavior. In addition to complete blood counts, serum chemistries, gastric and fecal cultures and cytology, and body weight, the subject should undergo gastroscopy to evaluate for ulceration, gastritis, or foreign body. Allowed to persist the condition can lead to severe weight loss, immune system compromise, increased susceptibility to disease, and death. Individuals should be closely monitored with serial weight determination to pick up early signs of deterioration. A complete behavioral evaluation should be conducted including a review of past relationships with peers and personnel, changes in training interaction, environment, and social structure. Often the animals are considered "loners", incompatible, placed outside the normal social structure by age or lack of suitable peers.

Individuals which continue to deteriorate may develop secondary problems with yeast infections or clostridial overgrowth so periodic medical exams should be performed. Treatment is geared to a number of additional concerns. Chronic regurgitation may lead to esophageal ulceration. Some individuals may benefit from lowering gastric ph. though overuse can result in retention of fish bones in the stomach. Use of smaller high calorie fish can decrease dietary breakdown time and provide fewer large pieces for manipulation. Overfeeding may also contribute. The young cetacean may require a complete change in training approach with a primary goal of piecing together those factors which may be involved in the development of the behavior. Relocation, separation from inappropriate social structures and a reevaluation of human interaction may be required.

Adult onset regurgitation is seen in older individuals often involved in social groups which undergo dramatic change. Loss of hierarchy status and new competition in enclosed inflexible environments may contribute. With chronic persistence and increasing frequency the animal may slowly become emaciated. As with juveniles the individual is prone to a number of medical complications and more likely to become ill. Weight loss can be mitigated by changes in fish size and ulcer control but the inciting factors must be determined and modified.

It is rare to totally eliminate regurgitation in extreme cases, but the goal is reduce the incidence and eliminate medical complications. Personnel must be educated to the chronic nature of this disorder and be aware of the visual cues of weight loss and the potential for recurrence.