Data from: Cultural turnover among Galápagos sperm whales

While populations may wax and wane, it is rare for an entire population to
be replaced by a completely different set of individuals. We document the
large-scale relocation of cultural groups of sperm whale off the Galápagos
Islands, in which two sympatric vocal clans were entirely replaced by two
different ones. Between 1985 and 1999, whales from two clans (called
Regular and Plus-One) defined by cultural dialects in coda vocalizations
were repeatedly photo-identified off Galápagos. Their occurrence in the
area declined through the 1990s; by 2000, none remained. We reassessed
Galápagos sperm whales in 2013–2014, identifying 463 new females. However,
re-sighting rates were low, with no matches with the Galápagos 1985–1999
population, suggesting an eastward shift to coastal areas. Their vocal
repertoires matched those of two other clans (called Short and Four-Plus)
found across the Pacific but previously rare or absent around Galápagos.
The mechanisms behind this cultural turnover may include large-scale
environmental regime shifts favouring clan-specific foraging strategies,
and a response to heavy whaling in the region involving redistribution of
surviving whales into high-quality habitats. The fall and rise of sperm
whale cultures off Galápagos reflect the structuring of the Pacific
population into large, enduring clans with dynamic ranges. Long-lasting
clan membership illustrates how culture can be bound up in the structure
and dynamics of animal populations and so how tracking cultural traits can
reveal large-scale population shifts.