Fascinating study shows killer whales take a single breath between dives –

Vancouver, British Columbia – For thousands of years, killer whales have captured our imagination with their intelligence, social bonds and powerful hunting skills. Yet despite decades of research, many aspects of their daily lives and physiology remain a mystery. Now a groundbreaking study led by scientists from the University of British Columbia and the Institute for the Oceans and Fisheries has shed new light on the breathing patterns and energy expenditure of these magnificent marine mammals.

The study, published in PLUS ONEused an innovative approach that combined drone footage, biologging devices and advanced statistical modeling to unravel the mysteries of killer whale breathing. By attaching special tags to the whales, scientists were able to record their diving behavior in unprecedented detail, while drones flying overhead captured video of the whales' surface activities.

One of the study's key findings is that killer whales take a single breath during each trip to the surface, whether they are resting, traveling or searching for food. This may seem like a small detail, but it has important implications for understanding the energy requirements of these top predators.

You see, every breath a killer whale takes is a window into its metabolism. Just like us, whales need oxygen to fuel their daily activities. The more energy they use, the more oxygen they have to absorb. By counting breaths and measuring the time between each surfacing, scientists can estimate how much energy a whale uses during different behaviors.

However, it's not as simple as just counting breaths. Like all mammals, killer whales have a complex respiratory system that allows them to store oxygen in their blood and muscles while diving. This means that they don't necessarily have to breathe in accordance with their physical exertion. Instead, during intense activities like hunting, they can build up an “oxygen debt” that they later repay by taking a series of deep breaths at the surface.

To explain this, the research team had to get creative. Using drone footage, they categorized each killer whale's behavior as either resting, traveling or foraging, and then matched that information with the tags' dive data. Next, they used a sophisticated statistical model called a hierarchical hidden Markov model to fill in the gaps and predict the whales' behavior during dives that weren't caught on camera.

The scientists found that young and adult male killer whales breathe most often while traveling, followed by foraging and then resting. This suggests that swimming long distances actually requires more energy for killer whales than foraging – a finding that challenges some previous assumptions.

On average, the young whales in the study breathed between 1.2 and 1.6 breaths per minute, while the adult males breathed slightly more frequently, at 1.3 to 1.8 breaths per minute. Using these breathing rates, as well as estimates of the whales' body size and oxygen storage capacity, the team was able to calculate the approximate amount of energy the whales used during each activity.

The young animals needed around 7.3 liters of oxygen per minute to search for food, around 7.4 liters to travel and 6.7 liters to rest. The much larger adult males had correspondingly higher energy requirements, consuming a whopping 35.2 liters of oxygen per minute while foraging, 43.6 liters while traveling and 25.8 liters while resting.

These estimates provide valuable insight into the daily energy budget of killer whales and can help scientists and policymakers better understand the nutritional needs of these marine predators. This information is particularly important in a rapidly changing ocean, where changing prey populations and increasing human activities can put pressure on killer whale populations.

But the implications of this study go beyond just killer whales. The innovative techniques developed by the research team, combining biologging, drone observations and advanced statistical modeling, could be applied to other marine mammal species to reveal their own respiratory secrets. As our technology and analytical methods continue to evolve, we may soon be able to paint an increasingly detailed picture of the hidden lives of these fascinating creatures.

Steve Fink, editor in chief of StudyFinds, contributed to this report.