Talk like a biostatistician

Anthropological methods — research techniques used to study human and animal behaviour, involving long-term, immersive observation to understand a culture or social group

Biostatistics — applying mathematical computation in biological research to distinguish reality from chance, helping scientists interpret complex data and draw reliable conclusions

Dorsal fin — the fin located on the back of a dolphin (and many other aquatic animals), often used by researchers to identify individuals based on its unique shape and markings

Ethologist — a scientist who studies animal behaviour, particularly in the species’ natural environments

Fieldwork — research conducted in an animal’s natural environment, outside of a lab setting or captivity

Grass-wearing — a behaviour observed in dolphins where they place pieces of seagrass on their dorsal fins, possibly as a form of social signalling or communication

Dolphins are among the most intelligent animals on Earth. Known for their playful behaviour and complex communication, they have long fascinated scientists and the public alike. But how much do we really understand about their social lives and emotional worlds? In recent years, researchers have begun to explore the idea that dolphins may possess aspects of culture – behaviours passed between individuals and across generations, much like in human societies.

Dr Ann Weaver, an ethologist and biostatistician at Good-Natured Statistics Consulting and the Maples Center for Forensic Medicine, College of Medicine, University of Florida, is investigating how bottlenose dolphins express themselves, form social bonds and respond to their environment. Through consistent observation and the use of statistical tools, Ann is helping us to understand not just how dolphins behave, but also why.

What does it take to study dolphins in the wild?

Ann has spent over 20 years observing wild bottlenose dolphins along the western coast of Florida in the southeast of the US. Her research involves conducting regular boat surveys, often several times a week, to observe dolphin behaviour in a consistent and non-intrusive way. “My job is to get to know some of the smartest animals on Earth on their own terms, in their own habitat,” says Ann. “You could call me a dolphin photojournalist using anthropological and statistical methods to understand a different culture without spoken language.”

Studying wild dolphins typically involves long hours on the water, tracking animals by sight and recording their behaviours and interactions. Because bottlenose dolphins live in warm, shallow waters, they are relatively accessible for fieldwork, but this requires a high level of consistency and patience. Over time, researchers can identify subtle patterns that only become visible through observation over many years. “My fieldwork has only changed over time because of my increasing familiarity with the dolphins and their ways,” explains Ann. “The more the dolphins trust me, the more they show me, the more I learn and the more I see. Happily, my methods for collecting data have been consistent and stood the test of time.”

Can dolphins recognise individual people?

Long-term field studies rely on respectful observation. Ethnologists maintain a strict hands-off approach – no touching, feeding or swimming with dolphins – to avoid influencing their natural behaviour. At the same time, they learn to tell individual animals apart. Dolphin researchers identify individual dolphins by the unique notch patterns on their dorsal fins, a method that allows scientists to recognise hundreds of animals by sight.

Familiarity develops on both sides, and there is evidence that dolphins notice who is watching them. “The dolphins recognise me too,” says Ann. “Among countless examples, one summer I started wearing a full-face mask for sun protection. Every time we approached the dolphins while I was wearing it, they refused to let us near and often fled at speed. But after seven weeks, I stopped wearing the mask and the dolphins allowed us to approach as closely as before. The mask scared them.”

Why do dolphins wear grass?

In recent years, researchers have begun to understand how dolphins use objects in their environment in more complex ways than previously thought. One such behaviour is ‘grass-wearing’, where dolphins drape blades of seagrass over their dorsal fins. “I knew that dolphins pay attention to how other dolphins look but initially assumed grass-wearing was accidental,” says Ann. “I realised it was intentional the day I witnessed a dramatic sighting: a mother dolphin, frantic over the death of her calf, donning grass to attract other dolphins’ attention, possibly to soothe her grief.”

To test her hypothesis, Ann examined her long-term dataset closely and applied statistical tools to look for patterns. She asked questions such as: Do all dolphins wear grass? Does it happen more often in certain conditions? Is grass-wearing linked to specific behaviours such as feeding or socialising? “My statistical analysis revealed that dolphins do indeed wear grass intentionally,” explains Ann. “This is what statistics do: reveal patterns that help us separate random events from wishful thinking about reality.”

What do the data reveal?

“Every time I saw a dolphin wearing grass, I recorded its identity, the identity of the dolphins it was with, what they were doing at the time, what happened next, how much and what kind of grass they wore, and the date, time and location,” explains Ann.

Using biostatistics, Ann analysed these records to find meaningful patterns. The results showed that grass-wearing is not accidental or limited to a few individuals – males, females, young and old all wear grass. The main context for grass-wearing is social. Dolphins seem to use it when new individuals arrive, as part of a friendly competition for attention. Interestingly, adult females wear grass regardless of whether they are fertile, pregnant or nursing, which suggests that grass-wearing is more than just ‘flirting’ or attracting a mate.

What does the future hold?

“Dolphin behaviour is a never-ending story,” says Ann. “I look forward to completing several future studies.” Ann has recently described how dolphins heal from injuries and is currently focusing on shark-dolphin interactions, two topics that are closely connected. Dolphins surface regularly, making them easier to observe, while sharks rarely come to the water’s surface, so direct observation of shark-dolphin interactions is difficult. Instead, researchers like Ann can study the evidence left behind, such as shark bite wounds and scars on dolphins.

Using patterns in dolphin behaviour to infer how dolphins and sharks interact, Ann aims to better understand how sharks and dolphins share their coastal environment. By identifying dolphin behaviours that would not occur if sharks were mindless predators, Ann hopes to challenge the negative stereotype of sharks.

Dr Ann Weaver
Good-Natured Statistics Consulting, Florida, USA

Fields of research: Biostatistics, primate behaviour, bottlenose dolphin behaviour

Research project : Using biostatistics to study bottlenose dolphin behaviour, communication and conservation. Ann seeks remote and in-person opportunities to teach animal and dolphin behaviour

Websites: dolphinsdigital.org

goodnaturedstatistics.com

About biostatistics

Biostatistics is the application of statistical tools to biological questions. It allows researchers to test hypotheses, detect patterns and make informed conclusions about complex natural systems – from genes to ecosystems. While it is a core discipline in medical research, it is equally important in ecology, animal behaviour, epidemiology, environmental science and more.

“Statistics lead to understanding, which leads to caring, which leads to conservation,” says Ann. “Statistics are little islands of conviction in seas of uncertainty.” In the broader scientific landscape, the field of biostatistics plays a crucial role by turning raw data into meaningful insights. It supports clear, evidence-based reasoning in areas where variability is the norm, helping researchers separate real patterns from coincidence.

“Future opportunities for biostatisticians are countless, and they are likely to pay well,” says Ann. “Computers let us collect mountains of data yet only a fraction of people knows how to analyse them.” While advances in artificial intelligence (AI) are creating new tools for data analysis, the human perspective will remain invaluable. A skilled biostatistician can ask contextually relevant questions, identify limitations and interpret patterns in ways that AI cannot.