Well, we don't just base the hypothesis that blue whales are the largest animal even on their size relative to estimated size of extinct species in general. It'

Well, we don't just base the hypothesis that blue whales are the largest animal even on their size relative to estimated size of extinct species in general. It's based on the phylogeny of quite a few extinct and extant whale species and other allometric and paleo-bio/ecological considerations that go into a model of a recent diversification of larger whales that has thus far culminated in the blue whale [1]. It doesn't appear individual species of whale were evolving gigantism really rapidly and out of nowhere from smaller species, but a gradual trend over tens of millions of years. It appears missing fossils that are extreme size outliers probably become less likely the further you go back in time from the past few million years. > Because finding fossils without funding is difficult Eh, not really. They don't occur in isolation typically, a formation/deposit or Lagerstätten [2] rich in fossils are accidentally discovered, word gets out at some point, and then international funding follows. [1] https://royalsocietypublishing.org/doi/full/10.1098/rspb.2017.0546 https://royalsocietypublishing.org/doi/full/10.1098/rspb.201.... [2] https://en.wikipedia.org/wiki/Lagerst%C3%A4tte https://en.wikipedia.org/wiki/Lagerst%C3%A4tte