Hook, a Cockburn Sound dolphin, was one of the chronic beggars, but is now missing. Credit: Hugh Finn

(Phys.org) -- Dolphins may learn harmful or undesirable behaviors, such as begging for food from humans, from each other, Murdoch University researchers have discovered.

After investigating the illegal feeding of Indo-Pacific bottlenose dolphins by recreational fishers in Cockburn Sound, a popular Perth waterway, researchers from the Murdoch University Cetacean Research Group (MUCRU) and the Conservation Medicine Program observed that dolphins were more likely to beg from humans if they associated closely with dolphins which had already learned to accept food handouts.

This begging behavior was also more likely if they spent more time in areas with large numbers of recreational fishers.

Over the course of a decade of monitoring, the researchers found that the number of dolphins who interacted with recreational fishers for food increased from one to at least 14 individuals  nearly 20 per cent of the dolphins resident in Cockburn Sound.

Marine biologist Bec Donaldson, from the Conservation Medicine Program, said the findings suggested that observing close associates beg for food might help dolphins learn how to become beggars themselves.

In humans, social learning allows novel behaviours to spread rapidly through societies. The case will be similar for many wildlife, she said.

Social learning makes sense in smart social animals like dolphins but most new behaviours are beneficial. It is worrying to see wildlife learning harmful behaviors.

Interactions between humans and wildlife are often dangerous, and may impact on threatened species. Our findings highlight how social learning may influence whether harmful behaviours spread through wildlife populations. We hope this knowledge informs policies to protect wildlife.

The researchers found that the dolphins which learned to beg from humans had higher rates of injury from boat strikes and entanglement in discarded fishing line. Humans are also at risk from accidental bites during the interactions, which are illegal under state and federal law. Fines of up to $10,000 apply.

The monitoring upon which the research is based took place between 1993 and 2003. MUCRU researchers carrying out more recent studies of dolphins in Cockburn Sound have said the greater enforcement by the Department of Environment and Conservation, extra signage and a community education campaign run in 2008 for 18 months had reduced but not eliminated illegal feeding.

Ms. Donaldson was the project officer on the federal government-funded community education campaign, entitled Keep Perths dolphins and sea lions wild, which saw her work with Rockingham Wild Encounters, DEC, councils and industry groups to construct signs and interpretive shelters at boat ramps and jetties, produce and distribute information pamphlets and give presentations to over 100 Perth classrooms.

We would like to expand this initiative across the state because our study suggests that even a small number of dolphins begging creates a risk of others engaging in the behaviour too, added Ms. Donaldson.

If humans do not feed dolphins, they will not get the opportunity to learn this damaging and dangerous behaviour from each other.

MUCRUs current Coastal and Estuarine Dolphin Project, which began in 2011, will allow researchers to follow up on the findings from 1993 to 2003.

Ms. Donaldsons paper on the research, which was co-authored by Dr. Hugh Finn, Associate Professor Lars Bejder and Dr. Mike Calver from Murdoch University, and Dr. David Lusseau from the University of Aberdeen, was recently published in the journal Animal Conservation.

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