Please Don’t Feed the Animals: the Spread of Maladaptive Behavior in Bottlenose Dolphins


Though hard to imagine, as inhabitants of such an urban environment, humans can play a large role in wildlife behavioral development. As our population grows and our use of terrestrial and aquatic habitats expands, we increasingly infringe on other organism’s territory. Animals that live in environments with frequent human contact can apparently become trained to embrace this interaction, particularly when rewarded with food. Rebecca Donaldson, at Murdoch University, School of Veterinary and Biomedical Sciences, in Perth Australia, took a look at a study gathered over the course of ten years (1993-2003), by another research team, on human feeding of bottlenose dolphins in southwestern Australia and its implications for dolphin behavior. Her findings were published in the October 2012 volume of Animal Conservation. Donaldson and her team discovered that the more time a dolphin spent in contact with boats, the more habituated they became to accepting food handouts. She also concluded that, similarly to humans, dolphins have the ability to learn behavior, such as eating human food, through watching other dolphins. Negative behaviors that can be spread through social interactions could have serious negative implications for conservation.

Finn et al. extensively studied a community of 74 bottlenose dolphins living in the bay Cockburn Sound in southwestern Australia from 1993 to 2003. The researchers gathered gender and age data on these individuals as well as observed their interactions with humans, particularly with fishers that illegally fed them. The dolphins were considered by Donaldson to be familiarized with human interaction if they swam up to a boat, remained close to it, exhibited eager behavior, and accepted food from humans if offered.  In 1993 only 1 dolphin in the population interacted with the fishers in this manner. That number jumped significantly to 14 dolphins at the end of the study in 2003. Donaldson set out to understand how the dolphins came to embrace this habit.

There are two ways that the dolphins could have come to know about this foreign food source. First, a dolphin could have individually discovered the food from humans and enjoyed the benefits, prompting them to keep going back for more. Second, it’s possible that dolphins learn to accept food from humans through interactions with the dolphins who originally discovered this food source.

Donaldson and her team specifically looked at this second, social learning, hypothesis among the dolphin community. Linear models were used to determine the effects four variables—age, sex, time spent in popular boating areas, and interactions with dolphins that were conditioned to human feeding—had on a dolphin becoming familiarized with accepting human food. The statistical analyses showed that age and sex were unrelated to the feeding behavior in this population. The dolphins that spent a lot of time in areas with many boats, and were therefore exposed to many human interactions, and those that interacted with other dolphins that had already eaten food provided by humans had a higher chance of becoming conditioned to the food themselves. Dolphins who were exposed more to humans had a higher risk of becoming accepting of food through operant conditioning, where humans offered food as a reward.  The second result, that dolphins can learn behaviors through social interactions, is a fairly new discovery with implications on conservation.

The purpose of this study was to apply the discoveries to wildlife conservation management. Determining that behavioral conditioning relates to the amount of time spent in interactions with humans provides an indicator for identifying other animal populations at risk for negative human-wildlife interactions. The more the humans and wildlife overlap, the more the animals will pick up new, and possibly maladaptive, behaviors. In addition to this concern, the interactions can be fatal to animals. The more the dolphins in this population interact with boats, the higher the likelihood that they get injured by one, or caught in fishing nets. Conservationists can pinpoint these human-wildlife interaction ‘hot spots’ and intervene before too much damage is caused. The second result, that learning maladaptive behaviors can take place within a species, can help wildlife experts predict how fast a certain behavior will spread in a population. Since humans are the source of the maladaptive behavior in the bottlenose dolphin case, and most likely with many other species, Donaldson believes that the most effective conservation strategies begin with educating humans and altering their interactions with wildlife. Since this study was conducted on a small population, future studies should be done to determine the relationship between learning behaviors and age and gender. Associations between these variables could further help conservationists pinpoint individual animals that would benefit the most from interventions.

Journal Reference:

Donaldson, R., Finn, H., Bejder, L., Lusseau, D. and Calver, M. 2012. The social side of human–wildlife interaction: wildlife can learn harmful behaviours from each other. Animal Conservation 15 (5): 427-435

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This entry was posted in Conservation Biology Posts, Conservation Blogs 2012-2013. Bookmark the permalink.

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