American porcupine

NUTRITION OF THE NORTH AMERICAN PORCUPINE, Erethizon dorsatum Kerrin Grant

EXECUTIVE SUMMARY

The North American porcupine, Erethizon dorsatum, is native to much of North America and is found in temperate habitats ranging from desert-shrub to tundra. Erethizon is the only porcupine genus found above the sub-arctic tree line (Roze, 1989). Because of the various habitats, adult weights range from 6-31 lbs. (2.7-14 kg).

Considered a generalist herbivore, porcupines consume tree bark, leaves, conifer needles, buds from conifers and deciduous trees, fruit and ground vegetation. Porcupines are nocturnal and active year round. The diet varies in composition and nutrient quality seasonally. The porcupine is a monogastric herbivore, hindgut fermenter. Microbial fermentation occurs in the cecum (Balows and Jennison, 1949; Odenyo, et al., 1999), which is approximately 6% of total body weight and is similar in size to the stomach (Johnson and McBee, 1967). Based on Kleiber's (1947) equation for basal metabolic rate (BMR), 70 x body weight (kg).75, and maintenance energy requirement (MER) value of 1.5, a 15 lb. (6.8 kg) porcupine would require 443 kcal/day. Felicetti, et al. (2000) and Fournier and Thomas (1997) reported maintenance nitrogen requirements (MNR) of 346mg. N/kg.75/day and 389.4mg. N/kg.75/day, respectively.

A comprehensive reference on feeding ecology includes Roze (1989). A good reference for digestive physiology is Vispo and Hume (1995). Felicetti, et al. (2000) and Fournier and Thomas (1997) have performed comprehensive analyses on nutrients, particularly protein.

SUMMARY OF CAPTIVE DIET

The challenges associated with a captive diet for North American porcupines include:

1. Providing adequate levels of crude protein, without offering excess which may contribute to

overweight.

2. Determining if browse, and associated secondary plant compounds, are required to maintain

proper nutrient balances (e.g. protein).

3. Providing appropriate levels of fiber for optimum protein absorption

4. Providing optimum vitamin and mineral levels, particularly vitamin D

At this time, a diet composed of a commercial rodent chow, an herbivore browser and/or high fiber biscuit as the base, with additional vegetables, browse and small amount of fruit should provide adequate nutrition in captivity. Diets high in protein or fat, and commercial diets manufactured for primates that are high in vitamin D3 should be avoided or at least minimized.