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Dolphin-human Interactions

Author Name: Georgia Oaten, BSc (Hons) Animal Behaviour and Welfare



Dolphins (Delphinus) have long inspired human fascination and desire for interaction. In the wild and captivity, humans attempt to develop relationships with dolphins, and an industry focused on facilitating the observation, swimming and meeting of dolphins has rapidly grown over the last decade. The dolphin interaction industry involves participants paying a fee in exchange for the opportunity to interact with dolphins. Human-animal interaction (HAI) does not constitute a unified field and this is seen in the literature pertaining to dolphin-human interaction. Across studies, there are themes of low statistical power, anthropomorphic projection, varying research designs, and observer bias, all of which hinder comparability of results. There is a clear need for the standardisation of terminology, studies focusing on the impact of HAI on the animal, and metrics to quantify the human interaction behaviours. There are 36 species of dolphin, but their use in organised HAI invariably only includes a few species. There may be species differences in HAI responses, suggesting variation of species would be beneficial. Understanding the effect of these programmes on the animal is important to ensure that they do not negatively impact welfare. This paper highlights the importance of longitudinal research, as behavioural responses detected in long term studies may not be present in short term studies. It additionally presents the argument that methodology should combine behavioural observations and physiological measures of dolphins, as use of behaviour alone can be misleading due to individual variation and a lack of understanding of the mechanisms driving behaviour.


1.0 Introduction 

Human-animal interaction (HAI) refers to the mutual and dynamic interaction between people and animals and how these interactions may affect physical and physiological health and wellbeing (Griffin et al., 2012). The majority of HAI research examines agricultural and companion animals, and there is a distinct lack of HAI research into wild and zoo animals. A literature review by Hosey and Melfi (2014) identified approximately 161 papers on companion animals, 76 on agricultural animals, 21 on wild animals and just 22 on zoo animals. The majority of HAI studies encompass primates, cetaceans, felids and ungulates, with a distinct absence of dolphin research (Baker and Wolen, 2008).  Additionally, the variation between papers’ scope and subject matter make comparison across environments and species challenging (Hosey and Melfi, 2014).

The literature highlights the need for further investigation of the effect on HAI on the animals participating in these programmes (Chandler, 2012).  There are few studies that focus on dolphin-human interaction, which is concerning due to the growing prevalence of dolphin-interaction programmes (Mayes, Dyer and Richins, 2004; Brakes and Simmonds, 2013). It is widely believed that people have an emotional need to connect with animals, which manifests as people visiting zoos and partaking in interaction programmes (Vinning, 2003; Myers, Saunders and Birjulin, 2004). Dolphin-interaction programmes consist of participants paying a fee in exchange for interaction with dolphins (Barnett et al., 2009). Due to the lack of data on the effect of dolphin-interaction programmes on participating dolphins, questions remains as to whether they are negative or positive experiences for the animals involved (López, 2012).


2.0 Critical Review

2.1 Captive Dolphin

Trone, Kuczaj and Solangi (2005) investigated changes in the behavioural repertoire of three dolphins, before, during and after trainer-controlled dolphin-interaction programmes. An increase in interaction initiated by the dolphin to humans outside of the programmes was observed. Trone (2005) concluded that the increase in dolphin-initiated interaction, alongside an increase in “play” behaviour after interaction suggested robust psychological health. However, the description of “play” was vague and included behaviours which may have been aggressive. Janik (2015) argued that the same behaviour reported as play are  indicative of a warning signal in the wild. Trone et al., (2005) interpreted the lack of behavioural changes and high prevalence of dolphin initiated interaction as suggestive that programme participation had no detrimental effect on the dolphin. In contrast, Frohoff and Packard (2015) identify a willingness by dolphin to initiate interaction with humans as assimilation, which is common in captivity.

Connor (2007) supports assimilation theory, evidencing that it can cause behavioural disturbances, as dolphin misread human behaviour and become frustrated. Assimilation is a more likely interpretation of the “play” seen, though this research was not available at the time. However, Schmitt et al., (2010) argue that humans can satisfy the fission fussion roles that are characteristic in dolphin social lives. Trone et al., (2005) findings imply interaction may be negative for welfare, however it is only an indication of situations where dolphins are involved in one trainer-controlled session a day and does not have wider application. Brensing et al., (2005) supported the former study by observing the behaviour of untrained individuals during dolphin-interaction sessions. Using non-trained dolphins indicated that the behaviour observed was self-motivated rather than the result of habituation. Data were collected over four years, enabling high statistical reliability, although environmental differences between the observation sites could account for differential reactions to the programmes (Chandler, 2012).  Findings could be the result of disturbance to the dolphin swim area.  This view is supported by Candelieri, Chiandetti and Cattaruzza (2013), who evidenced swim-with-dolphin programmes can cause suffering as result of environmental disturbance. Sew and Todd (2013) investigated the effect of HAI on dolphin in a robust study of behaviour, enclosure utilisation and social interaction, quantifying them to identify changes between interactions. Significant differences between individuals were seen and anticipatory behaviour was present. The study used a small observation set and observation quantities varied between individuals, which could reduce reliability as results may represent certain individuals’ reactions rather than a collective response.  The category of “play” was removed from analysis due to low incidences, however the lack of “play” could indicate distress, as evidenced by Paulos et al., (2010). Sew and Todd (2013) concluded that the participants’ welfare was not compromised by these programmes and this was supported by an increase in swimming and chasing behaviour that Henderson et al., (2012) and Jenson, Delfour and Carter (2013) describe as common play behaviour in the wild. Between observations there was a 10-minute gap that may have led to the loss of important information as the immediate pre and post effect of the swim with dolphins and meet with dolphins programmes were not recorded. Bejder et al., (2009) argued that if habituation was present in dolphins a change in behaviour may not be sensitive enough to identify a response to the stimulus and so may not have been observed.

Clegg et al., (2018) used sound cues to condition dolphin to positive HAI with a trainer and then measured anticipatory behaviour. Significantly higher frequencies of anticipatory behaviour before HAI resulted in the interaction being perceived as a reward event. The study was pseudo random, which decreased the likelihood of bias and multiple observations enabled a large data set and strong statistical analysis, however, there was variance in the history of the participants. The history is important as captive born or wild caught dolphin responses may differ, and individuals may seek human interaction as a result. The increase in anticipatory behaviour was concluded to have positive intrinsic value, however findings by Moe et al., (2006) suggest anticipatory behaviour is higher for negative experiences, though Yeates and Main (2008) and Clegg et al., (2017) argue that if anticipation is higher in negative states, then low participation would be seen. The findings have potential application to interaction programmes however Hill et al. (2016), Yeater et al., (2014) and Fabienne and Helen (2012) evidence that dolphins discriminate between familiar and unfamiliar humans and show preference for the former, which may indicate the anticipation was toward specific individuals.


2.2 Wild Dolphin 

Filby et al., (2014) investigated long-term responses of dolphins to swim with dolphin vessels from 1998-2013. Responses to swim with dolphin vessels changed across time, with avoidance and approach behaviours increasing significantly with cumulative experience. Greater levels of time and energy were spent avoiding, and approaching boats, potentially decreasing biological fitness by detracting from core biological activity.   A further study by Filby et al., (2017) looked at the effect of swim with dolphin vessels. Their findings showed that there was an effect on the behavioural activity budget. An increase in foraging, milling and socialising and reduction in foraging was seen. This study was carried out over three years, ensuring behavioural responses were steadily documented, increasing both reliability and statistical power. However socialising dolphins are more attractive to swim with dolphin vessels and operators target these groups, meaning the observed increase in social behaviour may be a result of observer bias. The paper was limited by excluding behaviours that occurred rarely. For example, “rest” was excluded from the results however work by Charlton-Robb et al., (2015) suggests that dolphins spend such limited time resting that any disturbance could be detrimental. By including this in the results it may have provided a more accurate representation of the effect of this programme. Though the short- term behavioural budget was significantly altered, the cumulative yearly budget was not, suggesting the programme may not have a detrimental effect on the targeted populations.

Behavioural changes were also observed by Perrtree et al., (2014) who investigated the percentage of sightings of dolphins involved in human interaction in Savannah over two years. The quantity of survey days changed by the year (44 surveys =2014, 25 surveys = 2015). This change may have impacted results as there were more data for one year than another. This means behaviour may have been missed and behaviour over the study years may not have been directly comparable. Begging was observed in 83 sightings and patrolling on 8 sightings, however begging on the ethogram was intermixed with patrolling, therefore levels of patrolling may have been lower or higher but may have been recorded as begging. This study varies from other literature in this area as it used a large sample size, producing stronger data and analysis. Increased aggression amongst conspecifics and towards humans were seen, with incidences of human injury and death; similar findings were documented by Cunningham-Smith et al., (2006).


2.3 Overview of dolphin-interaction literature  

Across the literature there is a theme of low participant quantity, resulting in low statistical power. Thus, caution should be taken when accepting the conclusions of the literature (Ellis, 2010).

Skewed sex ratios contribute to a lack of validity in studies; Samuels and Spradlin (1995) evidence that male dolphin are more likely to increase aggressive and sexual behaviour during non -controlled swim with dolphins sessions. Research highlights that there are differences in responses from the two sexes, however it is not considered in the discussion of the papers. Sex specific responses highlight the need for studies that target the appropriate species, sex and ages of the dolphin for accurate industry application (Marino, 2013).

The history of the participants is rarely explored in the literature but could be important to consider when evaluating findings as many captive dolphins were wild caught and there may be distinct differences in responses between captive born and wild caught dolphin (Marino, 2009). Research into dolphin-interaction programmes predominantly focuses on captive dolphin which is useful for management and welfare considerations, however captive results may be inappropriate for generalisation of the species (Trone et al., 2005).

Care should be taken not to misinterpret results, as when little or no effect is seen, it may be concluded that there is a lack of distress present from the programmes. However, this may be due to habituation, which may lead to inappropriate management decisions that could compromise wellbeing (Lussea, 2007).

There is a lack of diversity in the human participants that the dolphins interact with.  Most papers use the same age range and ethnicities of human participants. Thus, the results may be more indicative of responses to certain group types (Siniscalchi et al., 2012).

Methodologies vary between studies, although all of the studies use behavioural observations, the behaviours deemed important and the terminology to describe them differ (Marino and Frohoff, 2011).  Methodologies would produce more robust and valid results if the effect of participants, visitor presence and the effect of the programmes themselves were investigated, however this would be logistically difficult (Filby et al., 2014).

Due to the nature of the dolphin-interaction programmes, research varies between the type of interaction, e.g. whether they are controlled and involve familiar or unfamiliar humans. Due to the lack of uniformity, cross study comparison is unachievable (Scheer, 2010). The importance of longitudinal research in this area is highlighted throughout the literature, given behavioural responses detected in the long – term would not be detected in the short term. The need for comparability in this area is evident as HAI and the effect on behaviour in different species would inform collection managers and conservation organisations to help them know where to focus their efforts (Filby et al., 2017).


2.4 Comparison to Zoo Literature 

HAI in zoo literature appears in peer reviewed journals relatively few times and dolphin interactions even more infrequently. Zoo research often focuses on the effect of exhibit design and visitor presence on the behaviour of animals (Fernandez et al., 2009).  Methodology in this area is relatively standardised across different species, as most studies focus on the effect of interaction on the animals using behavioural observations. However, Miller et al., (2013) argues that the use of behavioural indicators does not provide a comprehensive and accurate understanding as no single biochemical or behavioural measure can be used to assess behaviour in response to interaction. Behaviour is a useful measure but can be misleading due to individual variation in stress reactivity, ability to cope and a lack of understanding of the mechanisms behind behaviour. This makes behaviour inappropriate to be used as the only indicator of negative or positive impact (Miller, 2011). A combination of physiological and behavioural responses would increase validity across studies. For example, Shepherdson et al., (2013) collected data from 55 bears housed across 20 zoos and used behavioural observations and faecal glucocorticoid levels for a year, which produced a reliable data set.

HAI studies are limited as there is a lack of consistent terminology across the field (Griffin et al., 2012). As the different disciplines use their own terminology there is a lack of agreed terms which means that findings may be interpreted differently depending on the nomenclature used in the paper. Furthermore, search engines do not always pick up relevant literature due to terminology variance (Griffin et al., 2012).   Throughout zoo and dolphin interaction literature it could be argued that there may be anthropomorphic interpretations of the results, for example behaviour associated with play or social attitude in dolphin may be disputed by ethological observations (Donaldson et al., 2012).

Zoo and dolphin interaction literature are similar as they focus on the humans’ perception of the experience rather than the effect on the animal and anecdotal results are often used to evidence the animal’s behaviour. However, this does not make for a reliable account of the behaviour (Carlstead, 2009).

Perceptual and cognitive misinterpretations need to be challenged to understand the effect of HAI on the animal’s wellbeing. Overall, the literature on zoo animals is similar to dolphin interactions but there is variance in the availability and quantity of research and due to the diversity of species, environments and terminology across studies it makes comparison and conclusions difficult. A standardised method of metrics should be produced to quantify HAI and allow application to the field, to enable research to be informative and meaningful (Christiansen et al., 2010).


3.0 Conclusion 

It is important to examine the short-term studies available into dolphin interaction and HAI and concurrently gain evidence into the behavioural changes that have occurred in response to HAI. The literature available highlights the importance of increasing long – term data sets in this area in order to increase the robustness and validity of the results gathered. Across the literature there are themes of low participant quantity, skewed sex ratio, one dimensional human participants and variable life histories which identifies a need for industry continuity. The terminology used within the subject matter requires quantification to ensure HAI and dolphin interactions are investigating unified responses. This will enable standardisation and uniformity across studies in terms of methodology, rationale and recording behaviour. In turn, this would enable comparability, analysis and review of the findings to gather well evidenced and accurate conclusions. It is necessary to create metrics to compare behavioural data against. This would allow for direct comparison, which may provide valuable data that can inform management and conservation efforts. The papers do not need a consensus on whether the behavioural responses should be deemed negative or positive to the individuals as results vary depending on the structure of the programmes, the appropriateness and consistency of methodologies and the collection and analysis of data. Further investigation is required to fully understand the impact of dolphin interaction programmes on the behaviour and welfare of dolphin and the effect of HAI on a broader range of zoo housed species whose daily routine involves interaction with familiar and unfamiliar humans.


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