Animals: Borrowed Muscle, the Oldest Multiplier

Long before humanity burned anything, it borrowed muscle, from oxen, from horses, from dogs, and multiplied its own strength many times over. It may be the most intuitive energy arbitrage of all, which is perhaps why it is so rarely counted as one.

Key Milestones

• Hunting, from roughly 15,000 BC onward. Domesticated dogs extended human senses and speed, making hunting considerably more reliable as a food source.
• Farming, from roughly 4000 BC onward. Oxen and other draft animals pulled plows, multiplying how much land a single farmer could work.
• War and transport, from roughly 2000 BC onward with chariots. Horses turned soldiers into cavalry and messengers into relay riders, compressing both battle and distance.

The Energy, Social, and Economic Impact of Animals

The arbitrage here is simple physiology. A human can sustain roughly 75 watts of continuous power output over a full workday. A medium-sized ox can sustain about 450 watts, and a horse about 746 watts, the literal origin of the term "horsepower," which James Watt coined by measuring a horse's steady work rate. Every farmer who hitched an ox or horse to a plow was arbitraging that six-to-ten-fold gap in output, and civilization scaled accordingly.

View chart in the full report

Unlike fire or coal, animal power is intuitive enough that it rarely gets credited as an energy technology at all, but it was humanity's primary energy multiplier for thousands of years, right up until steam finally offered something even a horse could not match.