Dear all,
My co-autors and me are happy to share our newest work, "Temporal patterns in Cape fur seal (Arctocephalus pusillus pusillus) mother and pup attraction calls". Please find the abstract and link to full text below.
Best,
Anna N Osiecka
Abstract:
Vocal recognition is widespread in the animal kingdom, and a necessary
tool for offspring survival in some groups. Temporal patterns of animal
vocalisations can facilitate communication and convey information such
as identity, emotional state, or motivation of the caller. While
pinniped (i.e., walrus, eared and true seals) vocalisations are
generally well studied, and captive pinnipeds show strong timing
abilities, little is known about the temporal structure of their calls
in the wild. Here, we followed Cape fur seals (Arctocephalus pusillus pusillus)
during spontaneous search efforts at the Cape Cross Seal Reserve in
Namibia. To investigate the temporal and rhythmic patterning of Cape fur
seal attraction calls, we analysed call bouts of 80 mothers and 148
pups. We assessed the relative vocal efforts undertaken by mothers and
pups by calculating calling rates, inter-call intervals (periods of
silence between vocalisations), and the total time spent calling per
bout. To explore the rhythmic structure of the calls, we visualised
their temporal patterns by plotting the calling events and frequency
histograms of the inter-onset-intervals between each two consecutive
vocalisations in a bout. A normalized Pairwise Variability Index was
calculated for each individual to investigate underlying patterns and
compared between mothers and pups. Pups produced more calls per search,
vocalised at higher rates, and took shorter breaks between consecutive
vocalisations than females. Even though female vocalisations were much
longer, there was no significant difference in the total time females
and pups spent vocalising per bout. All animals vocalised at seemingly
random intervals, with no distinguishable rhythmic pattern, suggesting
that these do not encode identity information during mother-pup
reunions. However, numerical analysis showed a potential asynchronous
patterning within the age classes, possibly used in anti-masking. Our
results indicate that Cape fur seal females and pups invest their energy
differently during a search, and while their total calling effort is
comparable, reunions seem to be driven mostly by the young.