Studies have found that you can analyze secretions in a whale's nose to assess its health. It is similar to swabbing the nose or mouth with a swab or spitting into a test tube for a coronavirus test. That does not mean you can take a large whale, 10 to 20 meters long, to a hospital or lab for testing. It is also difficult to approach by boat or dive to collect biological samples.
Scientists have developed an aerial testing method for diagnosing whales. They collect and analyze the water a whale exhales when it surfaces to breathe, using drones. With this method, they detected a deadly virus spreading among Arctic whales and identified gut microbiome imbalances that have contributed to declines in whale populations. In addition to land-based labs and ocean research vessels, drones have now joined whale protection, mobilizing land, sea, and air.
◇A deadly virus spreads among Arctic whales
A team led by Courtney Waugh of Nord University in Norway said, "We successfully collected exhaled blow from humpback, sperm, and fin whales in northern Norwegian waters using drones," in a study published on the 18th (local time) in the journal BMC Veterinary Research.
A whale's blowhole, or nose, is at the top of its head. When a whale surfaces to breathe, the warm air from its lungs meets the cold atmosphere and becomes vapor, forming a V-shaped spout from the blowhole. It is the same phenomenon as when vapor forms on glass when you breathe on it in winter. At that moment, water, mucus, and cells pooled in the blowhole are expelled together.
An international team of scientists from Norway, the United Kingdom, Ireland, and Iceland launched drones fitted with sterile culture plates to collect blowhole spray from humpback, sperm, fin, and sei whales across the Northeast Atlantic—from northern Norway and Iceland to Cabo Verde, an island nation off West Africa—from 2016 to 2025.
By analyzing nasal secretions from whales, the researchers confirmed for the first time that a deadly outbreak of "cetacean morbillivirus" is circulating among Arctic whales. The highly pathogenic virus infects whales, dolphins, and porpoises, damaging the respiratory, nervous, and immune systems. The team detected cetacean morbillivirus in a group of humpback whales in northern Norway, in a sperm whale that was in poor health, and in a sei whale that washed ashore dead.
Since it was first identified in bottlenose dolphins that died en masse in 1987, cetacean morbillivirus has been cited as a cause of several mass die-offs of cetaceans. Herpesviruses were also found in humpback whales across Norway, Iceland, and Cabo Verde, but avian influenza viruses or Brucella bacteria previously detected in beached whale carcasses were not found.
The aerial drone test has been hailed as opening a new era in whale research. Terry Dawson of the Department of Geography at King's College London (KCL), a co-author, said, "Collecting blow with drones is a game changer for whale research," adding, "It allows us to track pathogens and study infectious diseases in the rapidly changing Arctic ecosystem without stressing or harming live whales." Helena Costa, the first author and a doctoral researcher at Nord University, said, "We will use drones to monitor over the long term how new stressors affect whale health."
◇"Skinny" gut microbes hinder whale reproduction
U.S. scientists also succeeded in using drones to assess the health of humpback whales living off the east coast of North America. A team led by Amy Apprill at the Woods Hole Oceanographic Institution reported in the ISME (International Society for Microbial Ecology) Journal last month, "By analyzing drone-collected secretions, we have shown for the first time a link between the health of North Atlantic right whales and their gut microbiome."
From 2016 to 2024, Woods Hole researchers flew drones equipped with sterile culture plates into the stream of exhaled blow from whales. Using this method, they collected 103 secretion samples from 85 North Atlantic right whales living in Cape Cod Bay, Massachusetts.
The team said that analysis of whale secretions showed a link between the types of gut microbes and whale body condition. Just as certain human microbiome types are associated with obesity or a lean body, whale body condition is also influenced by gut microbes.
Humans may prefer "skinny" gut microbes, but whales are the opposite. Previous research found that female whales need sufficient energy-rich body fat to migrate from Nova Scotia in Canada and New England in the United States to calving grounds off Florida and Georgia. Underweight females cannot give birth properly. The new findings show that gut microbes also influence whale reproduction.
The researchers said, "North Atlantic right whales weigh up to 70 tons and are longer than a school bus, so taking them to an animal hospital is impossible," adding, "We have now opened the way to effectively monitor and protect North Atlantic right whales—an endangered species whose population has plummeted to fewer than 400—using drones."
◇Biological sample collection joins video filming
Drones have transfer been used in wildlife research. Drones are tasked with tracking whales in remote seas and groups of penguins and seals. The National Oceanic and Atmospheric Administration (NOAA) is tracking whale health using footage shot by rotary-wing drones. In 2019, by comparing footage shot over several years by drones 30 meters above pods of killer whales, it confirmed that the health of individual animals had deteriorated.
On land, drones are also active. The World Wide Fund for Nature (WWF) operates fixed-wing drones in India and Nepal to monitor poaching of tigers, elephants, and rhinos. Google also supports the project. In the United Kingdom, an animal protection group used helicopter-style drones to monitor whether aristocrats' fox hunts were skirting the law.
Following cameras, drones are now equipped with biological sampling gear, taking on the challenge of on-site health checks for wildlife. In 2023, researchers at ETH Zurich reported that they collected eDNA samples from 14 tree species and 21 terrestrial animal species using drones. eDNA refers to fragments of DNA from organisms extracted from various environments such as water, soil, and air, known as environmental DNA. By analyzing eDNA, researchers can identify which organisms inhabit a particular habitat without biological specimens. Thanks to this advantage, it is widely used in biodiversity research.
The Swiss team developed a drone outfitted with a special cage and force sensors that can land on trees. At the outer edge of the cage is an eDNA collector made of adhesive materials, such as tape or humidifying gauze. When the drone lands on a tree, the adhesive contacts the landing surface and picks up DNA.
References
BMC Veterinary Research (2025), DOI: https://doi.org/10.1186/s12917-025-05152-6
The ISME Journal (2025), DOI: https://doi.org/10.1093/ismejo/wraf231
Science Robotics (2023), DOI: https://doi.org/10.1126/scirobotics.add5762