Conservation issues arising from maladaptive behaviours spreading socially

摘要

Donaldson et al. (2012) describe the spread of a novel foraging tactic through part of a population of Indo-Pacic bottlenose dolphins (Tursiops sp.) in Cockburn Sound, Western Australia. Some dolphins in this population have learned to accept sh offered by humans. Initially, this behaviour was rare and had been observed in only one individual, but during the course of the study, the behaviour spread to a larger number of dolphins. The authors found that the dolphins using areas with high densities of recreational vessels and those associating more with previously conditioned dolphins were more likely to adopt this foraging tactic. There are two major implications of their ndings. First, a previous study in the same population revealed that accepting sh handouts from humans lead to higher risks of boat strikes and entanglement (Donaldson, Finn & Calver, 2010), making the spread of this particular foraging tactic a potential conservation issue. Second, and in my opinion even more surprising, a possible social transmission mechanism of this foraging tactic is consistent with the data and also plausible, given the well-established cognitive capacities of toothed whales in general and bottlenose dolphins in particular (e.g. Rendell & Whitehead, 2001; Herman, 2002). In a conservation context, it might just be semantics whether cognitively more demanding social learning mechanisms (such as imitation or emulation), or those that are less demanding (such as local enhancement, stimulus enhancement or social facilitation) explain the observed patterns. The main point is that potentially maladaptive behaviours can spread through a population.