Kangaroos – The 100 Days Project: Day 64 [37]

                    Grass 1

Comparative Consumption

Photo: Andras Berkes-Brandl

Ultimately it’s all about grass. There’s a lot to say about that, but for today the simplest post. A few basic figures. Comparative consumption.

Estimates vary, but the current wisdom is that one sheep exerts equivalent grazing pressure to between 2.63 and 5.00 kangaroos; that is, it takes between two-and-a-half and five kangaroos to eat the same amount of grass as one sheep. (Gordon Grigg, one of the sources here, in fact says the DSE might be as low as 0.15, i.e. approximately 6.66 kangaroos to eat as much as one sheep.)

This ratio is called ‘Dry Sheep Equivalence’.

As to cattle, the current international estimate is that it takes somewhere around or over twelve sheep to eat the same amount of grass as one head of cattle (a figure supported by Australian estimates). We might therefore (the DSE) quite legitimately assume that it takes somewhere between thirty and sixty kangaroos to eat the same amount of grass as one head of cattle.

Photo: Andras Berkes-Brandl

References:

The lower sheep figure (Dry Sheep Equivalence [DSE] of 0.2) comes from Gordon Grigg, ‘Conservation benefit from harvesting kangaroos’, in D. Lunney and C. Dickman, A Zoological Revolution: Using native fauna to assist in its own survival  (Mosman: Royal Zoological Society of New South Wales, 2002).

The higher sheep figure (DSE of 0.38) comes from Adam Munn et al, ‘Modelling digestive constraints in non-ruminant and ruminant foregut-fermenting mammals’, Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology, 151.1 (2008), 78-84.

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