Acoustic communication plays a fundamental role in coordinating social behaviors. From primates to elephants, social species use vocalizations to maintain contact, coordinate movement, and regulate social interactions. While the acoustic structure and contextual use of vocal signals have been widely studied, the temporal organization of vocal exchanges remains comparatively underexplored, despite increasing evidence that call timing carries meaningful social information and plays a central role in collective behavior. Here, we analyzed a dataset of semi-free African savanna elephants (Loxodonta africana) recorded in a standardized subgroup-separation context to elicit frequent contact rumbles. We applied three previously published methodological frameworks to the same dataset, each characterizing a different aspect of temporal coordination: quartile-based categories, bout criterion interval, and antiphonal probability analysis. We found that these statistical frameworks resulted in substantial variation in temporal boundaries and the classification of antiphonal signals, both within our dataset and relative to previous work. Quartile-based methods yielded shorter inter-call intervals, likely reflecting the high proportion of overlapping calls. Antiphonal probability analyses provided limited evidence for turn-taking across individuals. In contrast, bout criterion interval analysis revealed a comparatively longer temporal threshold, indicating that most vocalizations occurred within extended calling bouts. Overall, these findings demonstrate that methodological decisions strongly influence the identification and interpretation of temporal coordination, particularly antiphony, and can lead to differing conclusions about the presence and extent of coordinated vocal behavior. Consequently, given the limited number of existing studies on elephant vocal timing, early methodological choices may have a disproportionate impact on how temporal coordination is defined and detected, potentially shaping our understanding of coordinated vocal behavior in elephants.

Prey often assess predation risk using multiple sources of information that differ in immediacy and reliability. How prey differentially weight direct predator-associated cues and heterospecific alarm cues remains a central question in behavioral ecology. To investigate this, playback experiments were conducted on free-ranging, predator-experienced Southern giraffes (Giraffa giraffa), using lion (Panthera leo) vocalizations and red-billed oxpecker (Buphagus erythrorhynchus) alarm calls presented in different positions within sequential playback trials. Lion vocalizations consistently elicited strong vigilance responses regardless of playback presentation order, indicating that giraffes assigned greater behavioral weight to direct predator-associated information. Giraffes also responded to oxpecker alarm calls, although responses were generally weaker and more variable than responses to lion vocalizations, suggesting that indirect heterospecific cues were weighted less strongly than direct predator cues. Evidence that preceding playback exposure strongly influenced subsequent vigilance responses was limited, as lion vocalizations continued to elicit stronger responses than oxpecker alarm calls across successive playbacks. Females additionally exhibited generally stronger vigilance responses than males across playback conditions. Together, these findings suggest that giraffes differentially weight multiple sources of risk-related acoustic information during antipredator responses.Not all warning sounds mean the same thing to giraffes. Lion vocalizations triggered stronger vigilance responses than alarm calls from red-billed oxpeckers, while previous playback exposure had only limited influence on later responses. Female giraffes also responded more strongly than males. These findings suggest that giraffes differentially weigh direct predator cues and indirect warning signals when assessing danger, highlighting how large mammals integrate multiple acoustic information sources to evaluate potential predation risk under natural conditions.

IntroductionPredator recognition is essential for prey survival, yet, whether responses are shaped by evolutionary predispositions or by ecological experience remains debated.MethodsWe tested vigilance responses of fifty-one free-ranging Southern giraffes (Giraffa giraffa) to controlled playbacks of lion roar-grunt sequences in two South African populations: a predator-naïve population in a reserve without lions and a predator-experienced population in a reserve where lions were reintroduced five years ago.ResultsBoth populations oriented rapidly to lion calls, suggesting that acoustic features of lion vocalizations act as generalized danger cues. However, predator-experienced giraffes sustained vigilance ten times longer (mean ± SD: 513.34 ± 421.34 s, N = 24) compared to predator-naïve giraffes (49.06 ± 46.26 s, N = 27). Vigilance responses during lion playbacks, in general, were higher in the predator-experienced population, whereas responses to control calls did not differ between sites.DiscussionThese findings indicate that while immediate orientation likely reflects evolved sensitivity to acoustically harsh predator cues, the persistence of vigilance is shaped by ecological experience. Our study demonstrates that predator reintroduction can rapidly recalibrate prey risk perception, highlighting the dynamic interplay between evolved predispositions and learning in shaping antipredator responses.