, 2010a) showing the importance of the animal terminating the bout on the duration of the bout. In all three species the suckling bout duration was shorter when terminated by the mother than when terminated by

the foal. Similar results were observed in other ungulates as, for example, red deer Cervus elaphus (Bartošová, Ceacero & Bartoš, 2012) or babirusa Babyrousa babyrussa (MacLaughlin et al., 2000). Because we did not find any substantial interspecific differences among suckling bout duration terminated by mother, we suppose that the level of parent–offspring conflict (Trivers, 1974) did not differ highly among different zebra species. On the other hand the interspecific differences were most pronounced in bouts terminated by the foal. It shows that the foals of different species differed in their intention for how long

to suckle. As suckling bout duration should Sirolimus molecular weight not reflect milk intake (Cameron, 1998; Cameron et al., 1999), and because the foals in our study suckled longer when not terminated by the mother in species with higher rate of agonistic interactions among mares, our results support the suggestion that suckling bout duration reflect psychological needs of the young. In line with most studies on ungulates (Gauthier Panobinostat cell line & Barrette, 1985; Byers & Moodie, 1990; Green, 1990; Lent, 1991; Birgersson & Ekvall, 1994; Alley, Fordham & Minot, 1995; Špinka & Algers, 1995; Das et al., 2000; Dalezsczyk, 2004), we found that suckling bout duration and frequency decreased with increasing age of the foal in all three observed zebra species. However, in several ungulate species (cattle, impala Aepyceros melampus, Sumatran rhinoceros Dicerorhinus sumatrensis), suckling bout duration

is not affected by the age of the young (Lewandrowski & Hurnik, 1983; Mooring & Rubin, 1991; Plair, Reinhart & Roth, 2012) or even increased with an increasing age of the young (eland Taurotragus oryx; Underwood, 1979; common hippopotamus Hippopotamus amphibius; Pluháček & Bartošová, 2011). Therefore, we suggest that suckling bout duration seems to be better indicator of offspring medchemexpress needs than suckling frequency. This study offers the first detailed report of suckling bout duration and frequency in mountain zebra. Mountain zebras in the present study had the longest suckling bout duration when considering bouts terminated by foal of the three zebra species. This coincides with reports from the wild suggesting that ‘the total suckling time usually varies from 90 s to 2 min’ (Joubert, 1972a,b; Penzhorn, 1984), which are among the highest values reported for equids (Waring, 2003). On the other hand, we did not record any interruption 10 s before the end of the bout as reported from the wild (Joubert, 1972a,b; Penzhorn, 1984). The higher suckling frequency of mountain zebra recorded in our study compared with other studies on the same species (Joubert, 1972b; Penzhorn, 1984) could be explained by captive conditions including water availability.