Interspecific Communicative and Coordinated Hunting between Groupers and Giant Moray Eels in the Red Sea

Intraspecific group hunting has received considerable attention because of the close links between cooperative behaviour and its cognitive demands. Accordingly, comparisons between species have focused on behaviours that can potentially distinguish between the different levels of cognitive complexity involved, such as “intentional” communication between partners in order to initiate a joint hunt, the adoption of different roles during a joint hunt (whether consistently or alternately), and the level of food sharing following a successful hunt. Here we report field observations from the Red Sea on the highly coordinated and communicative interspecific hunting between the grouper, Plectropomus pessuliferus, and the giant moray eel, Gymnothorax javanicus. We provide evidence of the following: (1) associations are nonrandom, (2) groupers signal to moray eels in order to initiate joint searching and recruit moray eels to prey hiding places, (3) signalling is dependent on grouper hunger level, and (4) both partners benefit from the association. The benefits of joint hunting appear to be due to complementary hunting skills, reflecting the evolved strategies of each species, rather than individual role specialisation during joint hunts. In addition, the partner species that catches a prey item swallows it whole immediately, making aggressive monopolisation of a carcass impossible. We propose that the potential for monopolisation of carcasses by one partner species represents the main constraint on the evolution of interspecific cooperative hunting for most potentially suitable predator combinations

Many Associations between Groupers and Moray Eels Are Longer than Expected by Chance

<p>Observed frequency distributions of durations (min) of interactions between groupers and moray eels. The <i>x</i>-axis shows different time categories that were grouped in a non-linear fashion. The arrow almost above the 2 min time category indicates the average duration of associations (100 s) predicted by a null model, assuming independent movements of individuals of the two species.</p

The Two Predators Remain near Each Other During Joint Hunts

<p>Mean distance given as multiples of grouper body length (estimated 70 cm) between a grouper and a moray eel per minute association, analysed on screen from a 38-min film clip of a joint hunt that was already ongoing when the camera man joined. The gap in the data is due to the camera man focussing the lens on one individual such that nothing else would be seen on screen. Arrows indicate the timing of grouper signalling.</p

Berufseinstieg und erste Berufserfahrungen wirtschaftswissenschaftlicher Absolventinnen und Absolventen: Ein geschlechtsbezogener Vergleich

Maier GW, von Rosenstiel L, Wastian M. Berufseinstieg und erste Berufserfahrungen wirtschaftswissenschaftlicher Absolventinnen und Absolventen: Ein geschlechtsbezogener Vergleich. In: Abele AE, Hoff E-H, Hohner H-U, eds. Frauen und Männer in akademischen Professionen: Berufsverläufe und Berufserfolg. Heidelberg: Asanger; 2003: 113-128