THE EFFECTS OF ENVIRONMENTAL, SOCIAL AND BEHAVIORAL CONTEXTS ON THE MULTIMODAL COMMUNICATION PATTERNS OF PLAINS ZEBRA (EQUUS QUAGGA)

Abstract

The ability to communicate efficiently and effectively with other individuals plays a critical role in the lives of all animals as communication mediates reproduction and survival. And, therefore, context specific correlations are useful, if not essential, in suggesting how conspecific patterns in animal behavior and communication evolve and progress. In this this study we seek to better understand how Plains zebra (Equus quaaga) manage trade-offs between signal efficacy and the variable factors in which signaling may be specific to. We explore three such contexts, namely environmental and ecological, social and behavioral contexts and look at the posterior components of behavior, such as the frequency and length of behavior are impacted by these contexts. Based on these results we then look to see if flexibility in the multimodal communication systems of Plains zebra (Equus quagga) can explain the patterns we see. Preliminarily, we found that (1) zebra groups prefer some habitats to others, (2) zebra are located in different sized groups but group size doesn’t vary with habitat and (3) the occurrence rate of sexual and agonistic interactions do not decrease in dense habitat but the duration of the interaction is shortened, while the occurrence rate of social behavior decreased in dense habitat, in part perhaps because there is no significant difference in the length. This may imply inflexibility in how social behavior is communicated and signaled. We also found that the presence of stallions dampened the length of behaviors, perhaps due to the need of stallions to manage time and efficiency trade-offs. With these analyses in mind we looked at how these three contexts interact to modify behavior and allow Plains zebra to signal information across a wide range of situations and conditions. We found that woody vegetation buffers wind and that wind speed only affects the acoustic signaling of Plains zebra and no other modality, in two very interesting ways. The rate of contact calls increases in dense habitat but if variable in open habitat depending on wind and the time of day. Differences in group size did not affect how multimodal patterns of signaling change. And finally, we found that the occurrence rate of visual and tactile signaling decrease in dense habitat, while the occurrence of olfactory signaling increased almost 6x in dense habitat – the implications of which are that the communication systems of zebra have redundancies in signal content, especially in olfactory communication, that allow sexual and agonistic behavior to persist and social behavior to not in different environments.