Time spent suckling is affected by different social organization in three zebra species

Suckling bout duration and frequency were used in the past as an indicator of milk intake. However, later studies found no significant relationship between suckling bout duration and frequency and milk or energy intake. On the other hand recent studies are in line with the suggestion that suckling bout duration and frequency may express intensity of maternal care. The three extant zebra species differ in their ecology and social system. Mountain Equus zebra and Grévy's zebra E. grevyi live in an arid environment, whereas plains zebras E. quagga are found in savannah. Mountain and plains zebra mares form stable herds associated with high aggression and low aggression, respectively. Female Grévy's zebras form loose associations with the lowest level of aggression. The aim of this study was to re‐evaluate the suggestion that suckling bout duration and frequency are affected by social system. We observed suckling behaviour of 30 foals (16 plains zebras, 8 Grévy's zebras and 6 mountain zebras) at the Dvůr Králové Zoo, Czech Republic. We found that suckling bout duration was longest in mountain zebras, followed by plains and Grévy's zebras. Similar results were found for suckling frequency. These results coincide with the rate of aggression among mares; foals spent more time by suckling in species, where more aggression among adults occurred. Thus, the results of our study support the suggestion that suckling bout duration reflects social needs of the foal rather than milk intake requirements.