The differences in traits causing (and resulting from) indeterminate growth continues to confuse colleagues who are used to work with birds and mammals exhibiting determinate growth, i.e., reaching their maximum size quickly. See SharedIt link: rdcu.be/bRIwd
Here, my son and I criticize the notion that a mysterious “uncoupling” of brain growth from body growth causes the larger relative brain size observed in birds and mammals compared to all other lineages. Instead, it is the continuous high availability of oxygen/energy in endothermic birds and mammals which allows them to grow and maintain larger brains.
Birds and mammals pay the price for that because they have to constantly feed that metabolic “oven” or freeze or starve to death (or hibernate, but few can do that). We are thinking of it as normal, but it is actually mind-boggling how small deviations in body temperature or short periods of lack of oxygen will quickly kill us.
And yes, FishBase contains the largest collection of brain sizes for any group of organisms.