Female African elephant rumbles differ between populations and sympatric social groups

Vocalizations often vary in structure within a species, from the individual to the population level. Vocal differences among social groups and populations can provide insight into biological processes such as vocal learning and evolutionary divergence, with important conservation implications. As vocal learners of conservation concern, intraspecific vocal variation is of particular interest in elephants. We recorded calls from individuals in multiple wild elephant social groups in two distinct Kenyan populations. We used machine learning to investigate vocal differentiation among individual callers, core groups, bond groups (collections of core groups), and populations. We found clear evidence for vocal distinctiveness at the individual and population level, and evidence for much subtler vocal differences among social groups. Social group membership was a better predictor of call similarity than genetic relatedness, suggesting that subtle vocal differences among social groups may be lea..., Data collection
We recorded rumbles from wild adult female elephants in Amboseli National Park, Kenya (“Amboseli”) from 1986–1990 and 1997–2006 and in Samburu and Buffalo Springs National Reserves, Kenya (“Samburu”) from in Nov 2019–Mar 2020 and Jun 2021–Apr 2022. These two populations are 390 km apart with no current gene flow between them due to intervening urban development. Both populations have been continuously monitored for decades, and all individuals can be individually identified by external ear morphology. We focused on adult females (10+ years of age) to ensure that any vocal differences between populations or social groups were not an artifact of age or sex. Our final dataset included calls from 21 adult females in Amboseli (mean ± SD age = 26.2 ± 12.9 years) and 81 adult females in Samburu (mean ± SD age = 25.6 ± 11.2 years). The field recording methods for this dataset have been previously published.
We recorded the identity of the caller and the behavioral context of eac..., , ## Data from: African elephant rumbles differ between populations and sympatric social groups: possible consequences of vocal learning?

We investigated whether elephant rumbles contain acoustic signatures of individual caller identity, family group identity, bond group (collection of bonded family groups), or population. We recorded rumbles from wild African elephants in Samburu & Buffalo Springs National Reserves, northern Kenya and Amboseli National Park, southern Kenya, noting the identity of the caller and the behavioral context. We measured a suite of acoustic features on each call and used random forest models to try to assign calls to population, bond group, family group, and individual caller based on the acoustic features. We found that calls could be assigned to population and individual caller, but not family or bond group, with significantly better accuracy than the majority classifier that always guessed the most common category. However, when we calculated a proximity sco..., ,