Abstract

Despite the sugar glider's popularity as a pet and a long-term history of captive management in zoologic institutions, little is known concerning their specific nutritional requirements, apart from low basal energy and protein needs. Sugar gliders feed on plant and insect exudates—saps, gums, nectar, manna, honeydew, and lerp—as energy sources and rely on pollen and arthropods for dietary protein. Captive diets based on nutritionally balanced, commercially available products developed for other species, with added produce, have been fed successfully in zoo and private glider colonies, but these diets may not promote optimal gut function or feeding behaviors. Diets commonly fed by private owners were examined in feeding trials and were found to be highly digestible, but contained excess protein that was likely imbalanced in amino acids, as well as in calcium and phosphorus, because of improper supplementation. Suggestions are outlined for areas of relevant research to improve nutritional husbandry of sugar gliders.

Despite the popularity of sugar gliders (Petaurus breviceps) as a companion species in the United States, and a more extensive history of captive management in its native Australia as well as in zoologic institutions globally, a number of health issues potentially related to suboptimal dietary husbandry are still reported, including malnutrition, obesity, osteodystrophy, vitamin and mineral imbalances, and dental disease.^1,2 Physiologic requirements for energy and nitrogen determined for sugar gliders should be taken into consideration when developing feeding programs. Until more detailed requirements are established for other nutrients, nutritional principles for provision of balanced diets should be extrapolated from other species models, incorporating, if possible, life-history habits of this unique marsupial.

Sugar gliders (Petaurus breviceps) are nocturnal, omnivorous, arboreal marsupials that feed on a variety of plant and insect exudates and arthropods, with natural diet dependent on habitat characteristics and season. They have an elongated fourth digit to extract insects from bark, as well as enlarged lower incisors to chew into bark. Several studies of feeding ecology^3–6 in different locations in Australia indicate that diet is highly correlated with resource availability, and that sugar gliders are remarkably adaptable. Direct observations and fecal analysis in a 1-year study determined specific feeding activities, including feeding on Acacia spp gum and on sap (Eucalyptus spp), licking branches for honeydew (see below), peeling bark for arthropods, searching foliage for manna (see below), or randomly moving through eucalypts while catching flying insects and large foliage-dwelling insects.³ During spring and summer, gliders fed mainly on insects and spiders (40%–60% of time), even though exudates were most abundant, possibly to meet increased protein needs associated with reproduction. During autumn and winter, gliders spent most time consuming gum, sap, honeydew, and manna (a sweet mucilaginous secretion produced by plants in response to insect damage). Saps and gums were consumed year round and formed the staple diet.

In other studies of other glider colonies,^4,6 primary feeding activity focused on consuming Banksia and Eucalyptus flowers for nectar (energy) and pollen (protein) for much of the year, even when insects were abundant. Only in autumn did pollen incidence in feces decrease; pollen feeding directly correlated with flowering seasons, and gliders may be an important native pollinator. Sap and arthropods were important foods when flowers were not available. Gliders have been reported to strip the wings and legs off insects before consumption and to forage for insects on the ground.

Gum sites consist of holes made by insects into which gum accumulates; gliders often enlarge these holes using their incisors. Gliders also use incisors to strip bark and create sap-feeding sites by gouging into the phloem (nutrient transport) columns. Such behaviors may be important for maintaining tooth and gum health and should be encouraged, using natural materials such as nontoxic tree branch materials (ie, various branches with either smooth or rough bark). Gliders lick honeydew from branches and beneath bark and harvest manna from new leaves and flower buds through close examination, smelling, and licking. Cage furnishings that allow these natural feeding behaviors and food presentation can provide important environmental enrichment.