A single strand of hair might not look like much. But for scientists, it can hold months of information about diet, health, and environmental exposure.

New research from Mount Allison University shows that a portable X-ray tool can be used to track zinc along the length of a grizzly bear’s hair — offering a faster, non-destructive, non-invasive way to study how animals (and, someday, humans) take in essential nutrients over time.

The study, led by Mount Allison physics professor David Fleming, uses of portable X-ray fluorescence (pXRF), a compact technology that allows researchers to measure elements without damaging a sample. Unlike traditional lab techniques, pXRF requires minimal preparation and can be used outside of specialized lab settings.

Hair grows steadily, meaning each segment reflects what an animal was absorbing at a particular moment in time. By measuring zinc at regular intervals along a single hair strand, researchers can build a chronological picture of nutrient uptake across seasons.

In this study, the research team analyzed hair from ten wild grizzly bears in British Columbia. Using pXRF, they took measurements every two millimetres along each strand and compared the results with those from a well-established laboratory method known as laser ablation inductively coupled plasma mass spectrometry. 

For many of the hairs, the two methods showed similar patterns in zinc levels along the strand — an encouraging sign that the portable technique can reliably track changes over time.

“We’re interested in whether a tool like this can give us useful information quickly and non-destructively,” says Fleming. “Hair provides a natural timeline, and portable X-ray methods let us read that timeline in a much more accessible way.”

Zinc plays an essential role in growth, immune function, and overall health, and researchers around the world are exploring how zinc levels in hair might reflect nutritional status in both animals and humans.

The team also measured mercury in the same hairs to help interpret seasonal diet changes. Mercury is known to increase in grizzly bears during the fall salmon run, making it a reliable indicator of salmon consumption.

While mercury levels consistently reflected seasonal salmon intake, zinc did not always follow the same pattern. Some bears showed increases in zinc alongside mercury, while others did not — suggesting that zinc sources and uptake may be more complex than previously assumed.

Portable X-ray fluorescence offers several advantages: it’s fast, relatively low-cost, non-destructive, and potentially usable in the field. If further refined and validated, the technique could support wildlife research, conservation work, and even future studies of human nutrition—especially in situations where access to full laboratory facilities is limited.

“This study shows that portable X-ray methods can meaningfully track zinc along a single hair,” says Fleming. “That opens the door to new ways of studying nutrition and environmental exposure over time.”

The researchers emphasize that more work is needed to improve calibration and consistency, but the results demonstrate clear potential.