You can't just plop a scale into the ocean and ask a whale to get on it.
Scientists studying the body mass of whales have had to weigh stranded or dead animals, which can mean dealing with bloated or decaying bodies, making accuracy a challenge. Scientists have now figured out a better way to weigh by using drones.
A team of researchers led by the Aarhus Institute of Advanced Studies in Denmark and the Woods Hole Oceanographic Institution in Massachusetts published a study on the drone method this week in the British Ecological Society journal Methods in Ecology and Evolution.
The scientists used drones to snap aerial photographs of southern right whales off the coast of Argentina, where lots of the animals gather in clear waters. The researchers developed a model that lets them calculate body volume and mass from these images.
The drone-and-modeling approach works well for whales, but it could be adjusted and applied to other marine animals that are tricky to weigh. It also gives researchers the ability to track animals over time to keep tabs on their long-term health.
"Weight measurements of live whales at sea can inform how chronic stressors affect their survival and ability to produce offspring," said Michael Moore, a Woods Hole biologist and co-author of the paper.
The team worked with the Digital Life Project at the University of Massachusetts at Amherst, a nonprofit initiative that creates digital 3D models of living organisms, to create a full-color 3D model of a right whale you can view and download on Sketchfab. Now we just need a volunteer to 3D-print a life-size version.