Protein turnover rates are about 23% lower in parma wallabies than in eutherian species and BMRs of marsupials are also approximately 30% lower than those seen in eutherian mammals (White R.G. et al, 1988) and the maintenance requirement for true digestible nitrogen for the parma wallaby ranges between 477 - 566 mg/MBW (metabolic body weight; body weight^0.75) per day (Hume I.D., 1986). The largest factor that will effect an individuals BMR is its habitat, with higher requirements recorded in animals that live in moist forest, such as the parma wallaby, and lower requirements for animals that live in arid habitats (Hume, 26-27. 1991). Parma wallabies range from 2.6 - 6 kg in weight (Nowak R.M., 1991), therefore their basal metabolic rate (BMR) based on the calculation BMR = 46.6*(BW)^0.737 (McNab B.K., 2008) ranges from 94 - 175 kcal/day, and their daily energy expenditure (DEE) ranges from 2.6-6 kg is 216.2 - 402.5 kcal/d (using DEE = 2.3 x BMR). This means that a male parma wallaby needs to eat 29 kcal/kg and a female needs to eat 36 kcal/kg in order to maintain their maintenance energy which includes normal body processes such as protein synthesis/ turnover which makes up about 15 - 20% of total BMR (White R.G., Hume I.D., & Nolan J.V., 1988).
Now let's compare these numbers to red kangaroos that range in weight from 40 kg (females) to 90 kg (males) (Dawson T.J., 1995). Based on these numbers, the BMR range for red kangaroos is 706.5 - 1284.3 kcal/d (based on the same equation used above), and their DEE ranges from 1625 - 2954 kcal/d. This means that a female that weighs 40 kg needs to eat 17.7 kcal/kg and a male that weighs 90 kg needs to eat 14.3 kcal/kg. It should be obvious now that the BMR for smaller animals is much higher than that of a larger animal per unit body weight (i.e. a 2.6 kg animal needs to eat 36 kcal/kg while a 90 kg animal only needs to eat 17.7 kcal.kg).
So far we've looked at the energy requirements required just for basic maintenance, so now let's take a look at the energy expenditure required for pregnant and lactating parma wallabies and red kangaroos. The equations available for pregnant and lactating mammals are both presented as ranges, therefore I used an average weight for females based on data presented by Nowak and Maynes.
For an average female weight of 3.4 kg for parma wallabies:
BMR = 46.6 x (3.4)^0.737 = 114.8 kcal/d
Energy expenditure of a pregnant female = 2.7 to 3.1 x BMR = 310 - 356 kcal/d
Energy expenditure of a lactating female = 4 to 7 x BMR = 459.2 - 803.6 kcal/d
For an average female weight of 33 kg for red kangaroos:
BMR = 46.6 x (33)^0.737 = 613.1 kcal/d
Energy expenditure of a pregnant female = 2.7 to 3.1 x BMR = 1655.4 - 1900.6 kcal/d
Energy expenditure of a lactating female = 4 to 7 x BMR = 2452.4 - 4291.7 kcal/d
Based on the daily energy expenditure calculated above, which includes energy required for maintenance, activity and thermoregulation, a mature, non-lactating/pregnant adult parma wallaby which ranges in weight from 2.6 - 6 kg needs to eat approximately 80 - 150 g of paspalum grass per day to meet its energy needs.
Lastly, energy required for a growing marsupial (BMR) is approximately 2 times greater than the BMR of a fully mature adult marsupial. Juvenile red kangaroos have a BMR (maintenance and growth) that is 1.7-1.8 times that of a mature, reproductive female (Munn A.J. & Dawson T.J., 2003).
Now let's compare these numbers to red kangaroos that range in weight from 40 kg (females) to 90 kg (males) (Dawson T.J., 1995). Based on these numbers, the BMR range for red kangaroos is 706.5 - 1284.3 kcal/d (based on the same equation used above), and their DEE ranges from 1625 - 2954 kcal/d. This means that a female that weighs 40 kg needs to eat 17.7 kcal/kg and a male that weighs 90 kg needs to eat 14.3 kcal/kg. It should be obvious now that the BMR for smaller animals is much higher than that of a larger animal per unit body weight (i.e. a 2.6 kg animal needs to eat 36 kcal/kg while a 90 kg animal only needs to eat 17.7 kcal.kg).
So far we've looked at the energy requirements required just for basic maintenance, so now let's take a look at the energy expenditure required for pregnant and lactating parma wallabies and red kangaroos. The equations available for pregnant and lactating mammals are both presented as ranges, therefore I used an average weight for females based on data presented by Nowak and Maynes.
For an average female weight of 3.4 kg for parma wallabies:
BMR = 46.6 x (3.4)^0.737 = 114.8 kcal/d
Energy expenditure of a pregnant female = 2.7 to 3.1 x BMR = 310 - 356 kcal/d
Energy expenditure of a lactating female = 4 to 7 x BMR = 459.2 - 803.6 kcal/d
For an average female weight of 33 kg for red kangaroos:
BMR = 46.6 x (33)^0.737 = 613.1 kcal/d
Energy expenditure of a pregnant female = 2.7 to 3.1 x BMR = 1655.4 - 1900.6 kcal/d
Energy expenditure of a lactating female = 4 to 7 x BMR = 2452.4 - 4291.7 kcal/d
Based on the daily energy expenditure calculated above, which includes energy required for maintenance, activity and thermoregulation, a mature, non-lactating/pregnant adult parma wallaby which ranges in weight from 2.6 - 6 kg needs to eat approximately 80 - 150 g of paspalum grass per day to meet its energy needs.
Lastly, energy required for a growing marsupial (BMR) is approximately 2 times greater than the BMR of a fully mature adult marsupial. Juvenile red kangaroos have a BMR (maintenance and growth) that is 1.7-1.8 times that of a mature, reproductive female (Munn A.J. & Dawson T.J., 2003).