The drone did not, for obvious reasons, have to try to pick up the whales. Instead, it was simply flown over them while they swam in clear water off the coast of Península Valdés, Argentina. The DJI Inspire 1 Pro drone used in the study took pictures of 86 southern right whales and used its laser rangefinder to determine how far away from it the whales were.
The team used the photos and the laser measurements to determine each whale’s length, width and height. They then plugged that data into a custom formula that calculated the whales’ body volume, from which they could figure out the creatures’ density and their approximate weight.
“Knowing the body mass of free-living whales opens up new avenues of research," said Assistant Professor Fredrik Christiansen, lead author of a paper on the study. "We will now be able to look at the growth of known aged individuals to calculate their body mass increase over time and the energy requirements for growth. We will also be able to look at the daily energy requirements of whales and calculate how much prey they need to consume.”
