Bodies as measuring tools | Māori and ancient civilisations

Long before rulers, tape measures and the metric system, people relied on the most accessible tool they had—their bodies. Far from being rough guesses, these systems were practical, sophisticated and often exact. In Aotearoa, Māori developed intricate inenga (measurements) to guide the carving of waka, the construction of wharenui and the artistry of tā moko. In this article, science communicator Ceana Priest explores how body-based measuring shaped complex structures and specialised tools across history.

A global history of measurement

Measuring with body parts is a near-universal practice, found in cultures all over the world. In 2022, Helsinki scientists published a study titled Body-based units of measure in cultural evolution, which showed that body-based systems were used across nearly 200 past and present societies, often forming the base of measurement systems. Even as early as 2700 BCE, the ancient Egyptians used the royal cubit—about 52.3 centimetres—based on the distance from the elbow to the fingertips.

*It’s thought that the Great Pyramid of Giza / Pyramid of Khufu (which served as the tomb of pharaoh Khufu*) was designed and built using the Egyptian royal cubit as a primary unit of measurement. Its base was originally 440 cubits wide, and its height was 280 cubits. The royal cubit was approximately 523.5 millimetres long. [Pixels Douwe C. van der Zee CC BY-SA 4.0]

The imperial foot came from the length of an average foot, later fixed at 12 inches (30.48 centimetres), while the hand—still used to measure horse height today—was based on palm width and standardised at 4 inches (10.16 centimetres). Horse traders used their palms because they didn’t carry rulers.

The fathom, from the Old English word fæðm (meaning embrace), measured the span of outstretched arms (equivalent to 6 feet or 1.8 meters) and was handy for sailors gauging rope or sea depth. Roope Kaaronen, a cognitive scientist who co-authored the study, noted how practical it was: “If you measured [a rope or fishing net] with a yardstick, it would be quite cumbersome. But measuring slack items with the fathom is very convenient: Just repeatedly extend your arms and let the rope pass through your hands”.

The term inch comes from the Latin uncia (‘a twelfth’) and was once based on thumb width. Today it’s standardised as 25.4 millimetres. ABOVE: Mid-19th-century tool for converting between different standards of the inch. [ChrisO CC BY-SA 3.0]

Body measurements were (and still are) easy to use and quickly available, ideal for quick estimates and everyday tasks. They also tend to result in better ergonomic designs—tools and objects that naturally fit the user. An often-overlooked advantage is that it avoids the one-size-fits-all approach of rigid industrial standards: the Yup’ik and Greenlandic Inuit peoples sized kayaks and paddles precisely to their bodies for optimal fit; Zapotec farmers used their bodies to size ploughs and axes, reducing strain during labour and bows and spears were traditionally made to match the user’s reach, an approach still common in modern archery.

The study found that cubits, hand spans and fathoms appeared in about 40 per cent of the 186 cultures studied—making them some of the most widespread body-based measures. These maps illustrate the spread of the four most common body-based units of measurement. [Credit]

Māori innovation: Precision without rulers

In Aotearoa, early Māori developed highly sophisticated body-based measurement systems to construct intricate carved canoes, grand wharenui (meeting houses), expertly woven textiles, and precise tā moko (traditional tattooing). These methods were accurate and flexible, demonstrating high levels of craftsmanship.

Some units were tiny and precise, while others stretched the full length of a person. At the smallest end were measures like the kōnui (first joint of the thumb length) and the kōiti (little finger length). The ringa (width of a hand) and matikara (span of thumb to little finger when spread wide) offered larger, hand-based units. For arm-length measures, Māori used the tuke (cubit) (elbow to fingertips) and the mārō, whanganga or aronui, a full span of outstretched arms—similar to the fathom—which could also be curved into a pae to measure round objects like tree trunks. And, the hau (half an arm span – half a maro – from chest to fingertips).

Another measurement was the takoto, taken by lying flat on the ground with one arm stretched past the head. Chiefs were recorded using this method to measure ships. Longer still was the kumi, equal to ten mārō. The existence of kumi suggests Māori may have used a base-10 system—counting in tens—much like we do today. This is considered a crucial step towards developing a more scientific measurement method.

*Explore an interactive map (in English and Te reo Māori) illustrating how measurement affects our daily lives on the Measurement Standards Laboratory website.*

The rauru: Standardising the body’s blueprint

While individual body sizes vary, Māori engineers addressed this challenge for consistency, especially during important building projects. They would sometimes designate a chosen person, often a respected figure like a chief, whose body served as the standard for that particular task or building. To ensure accuracy and consistency across the team, these chosen body measurements were transferred onto a wooden rod or cord called a rauru. The rauru became a reference tool to maintain accuracy.

Some rauru rods were highly prized possessions, kept for many years, and even passed down through generations as taonga (treasures). These rods were usually crafted from strong wood, such as akeake (hopbush), and sometimes elaborately decorated with carvings or shell inlays, adding to their aesthetic and cultural value.

Māori also used ropes or cords, called taura, for measuring, particularly when planning the layout of a house on the ground. These cords could be marked with the different body-part measurements, such as the mārō (arm span), providing a flexible and accurate way to transfer designs.

The rise of the metric system

Today, most modern societies use the metric system, introduced in France in 1795 to replace a confusing mix of over 250,000 local units—ranging from body parts to grains of barley—and to simplify trade and science. Officially known as the International System of Units (SI), it’s based on the metre, kilogram and second, and their decimal multiples and sub-multiples. Designed by scientists, the system uses powers of ten for easy conversions and is tied to natural constants rather than local customs. For example, the metre was initially defined as one ten-millionth of the distance from the North Pole to the equator (measured along the meridian passing through Paris). Over time, the system spread globally and is now used almost everywhere, except in a few countries like the United States, which still primarily uses the U.S. customary system.

*The unofficial public imperial measurement standards erected at the Royal Observatory in Greenwich, England , in the 19th century [Rept0n1x CC BY-SA 3.0]*

Who controls measurement in New Zealand?

The Measurement Standards Laboratory (MSL) is New Zealand’s national metrology institute, part of Callaghan Innovation. It maintains the country’s official measurement standards and ensures they align with international systems. MSL works across a broad range of measurement areas, including time and frequency, temperature, mass, length, pressure, electrical current and light. Its role supports scientific research, industrial processes, trade, and regulation by providing accurate and traceable measurements.

Ngā kupu

Inenga: measurement
Mātauranga hanga poti: boat building, shipwright skills
Mēhua: to measure
Rūri: to survey (land), measure, surveyed, ruler
Tāraitanga: fashioning, shaping, building, sculpture

[Sourced from Te Aka Māori Dictionary]