Energy Saver

Easily a candidate for a Caption Contest. Yet there's more to this than a barrel treadmill of monkeys, something called science (courtesy of National Academy of Sciences).

Cutting Advice: It turns out that humans walking on 2 legs use only a quarter of the energy that chimps use while knuckle-walking on 4 limbs.

As Sludge has learned over time: An individual can save energy moving around...and can spend more of it on reproduction.
[ahem, Sludge Generation II].