Figure 1. Pliocene through Holocene eustatic sea-level changes, at two different scales.

Sea-level change [43] juxtaposed with A) the oldest known fossil belonging to the genus Eschrichtius, from the Pliocene of Japan (dashed line) [98]; and B) the relative temporal ranges from other historical gray whale data, with the oldest example belonging to the species occurrence (solid line), from the Palos Verdes Peninsula of California [101], [104]. Age for census estimates reflects an upper bound for reports from the written historical record [28], [29], [92], [93].