Bottlenose dolphins (Tursiops truncatus) are facing a growing health crisis linked to their social behavior. A new study published in Communications Biology reveals that synchronized breathing—a bonding behavior where dolphins surface for air together—may also be a key factor in spreading dangerous respiratory diseases such as Morbillivirus.
Dolphin Health Threat: Morbillivirus Outbreaks
Over the past few decades, bottlenose dolphins have suffered mass die-offs due to Morbillivirus infections. This virus causes severe health complications similar to pneumonia, encephalitis, and immune system damage. Much like how humans spread colds and flu through sneezing and airborne droplets, dolphins transmit Morbillivirus when infected individuals release water particles into the air during breathing.
Social Behavior vs. Disease Risk
Synchronized breathing is especially common among juvenile dolphins and, to a lesser degree, adult males. This behavior helps strengthen social bonds that are valuable later in life. However, close-range breathing also increases the chance of inhaling virus-containing droplets, making disease transmission more likely.
The international research team—including experts from Bangor University, Georgetown University, Duke University, and NOAA—investigated whether this social trait accelerates viral spread among dolphin populations. Their findings confirm that synchronized breathing significantly raises infection risks.
Dr. Ewa Kryzyszczyk, a zoology lecturer at Bangor University, explained:
“Our findings suggest that synchronized breathing is one of the factors responsible for the spread of Morbillivirus in dolphin populations. While it strengthens social bonds, it also increases disease transmission.”
Interestingly, dolphins are known to synchronize their breathing more often in the presence of boats and human activity, which could further amplify risks in infected groups.
Dolphins as a ‘Sentinel’ Species
Bottlenose dolphins are considered a sentinel species, meaning their health reflects the condition of the broader marine ecosystem. Rising ocean temperatures, pollution, and human-driven environmental changes are increasing their exposure to pathogens.
Past outbreaks have devastated populations. For example, more than 1,650 dolphins died along the US Atlantic coast during a two-year Morbillivirus outbreak, with populations declining by over 40%.
Who Is Most at Risk?
The study compared dolphin populations in the Potomac-Chesapeake Bay (USA) and Shark Bay (Australia). Both resident and migratory dolphins showed similar patterns:
- Juveniles had the highest infection risk since they synchronize breathing most frequently with peers.
- Adult males were also highly vulnerable.
- Adult females and calves were less likely to spread or contract the virus.
If juveniles introduce the virus into a group, outbreaks spread more rapidly. This insight is vital for predicting which groups are most vulnerable during future epidemics.
Conservation Implications
Understanding how synchronized breathing influences disease transmission helps scientists and conservationists design better protection strategies. For example, reducing boat-related stress in dolphin habitats during known outbreaks could lower synchronized breathing rates and decrease infection risk.
The findings also extend beyond bottlenose dolphins. Other species, such as the Guiana dolphin, already under threat from Morbillivirus, could benefit from similar conservation measures.
Reference
Collier, M. A., Kryzyszczyk, E., et al. (2025). Breathing synchrony shapes respiratory disease risk in bottlenose dolphins. Communications Biology. DOI: 10.1038/s42003-025-08161-1