Why are fish brains so small?

8 Dec

Fascinating speculation about fish brain size

neuroecology

I’ll take “questions I didn’t realize I was interested in”. The deeper you go in the ocean, the smaller brains get. From the abstract:

Here, we test three hypotheses of brain size evolution using marine teleost fishes: the direct metabolic constraints hypothesis (DMCH), the expensive tissue hypothesis and the temperature-dependent hypothesis. Our analyses indicate that there is a robust positive correlation between encephalization and basal metabolic rate (BMR) that spans the full range of depths occupied by teleosts from the epipelagic (< 200 m), mesopelagic (200-1000 m) and bathypelagic (> 4000 m). Our results disentangle the effects of temperature and metabolic rate on teleost brain size evolution, supporting the DMCH. Our results agree with previous findings that teleost brain size decreases with depth; however, we also recover a negative correlation between trophic level and encephalization within the mesopelagic zone, a result that runs counter to the expectations of the…

View original post 186 more words

3 Responses to “Why are fish brains so small?”

  1. enrique December 8, 2015 at 6:52 pm #

    It’s amazing such tiny brains work at all

    • jecgenovese December 10, 2015 at 5:48 pm #

      Even more amazing are the brains of honey bees. They engage in some very complex information processing with only a few hundred neurons.

      • enrique December 10, 2015 at 11:40 pm #

        Spiders too

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: