Sanvito, S., F. Galimberti and E. H. Miller (2007).
Observational evidences of vocal learning in southern elephant seals: a longitudinal study.
Ethology 113: 137-146.

Vocal learning in mammals is sparsely documented, and there are few reports of
vocal learning by wild mammals. In particular, no information based on
longitudinal data for identified individuals exists, even for well-studied
highly social species in which vocal communication is an important aspect of
social life. We present such information for the southern elephant seal
(Mirounga leonina). We studied a small breeding population in the Falkland
Islands over 8 yr (1995–2002). We recorded approx. 2400 agonistic vocalizations
from approx. 285 different males, including many recorded over more than one
breeding season (55 males were recorded for >2 yr and 29 were recorded
throughout vocal development). Vocalizations are a key element of male agonistic
behaviour in this species, the world’s most polygynous vertebrate. For male
agonistic vocalizations, we show that: (1) a limited number of discrete vocal
types exists; (2) proportions of vocal types change over time; (3) observed
trends of increase or decrease of vocal types are well explained by a process of
vocal learning, in which younger peripheral males imitate vocal types of older
more successful breeders.