Bigger brain = less offspring and guts

Studies of guppies show that bigger brains may mean "smarter" fish, but less offspring. Credit: Marrabbio2/Creative Commons
 
...at least for guppies. Dr. Alexander Kotrschal and colleagues at Uppsala University (Sweden) either shrank or grew the brains of guppies over multiple generations to create animals with up to 8-10% variations in brain size. To test for "smartness" they had the fish count by training the animals to look for food where a card with two or four symbols was shown. According to the researchers, the animals with larger brains tended to learn the task, whereas those with smaller brains did not. The downside to being a bigger-brained guppy was fewer offspring and a smaller gut size. Dr. Kotrschal suggested that larger brains in primates may also be associated with fewer offspring compared to other mammals.
 
Other recent research from Dr. Maklakov from Uppsala University (Sweden) shows that urban songbirds tended to have larger brains (relative to body size) compared to their rural counterparts.  The author of the study speculated that urban life requires bigger brains to handle its many challenges. 
 
Source:

More like this

The streams of Trinidad and Tobago are home to the most unexpected of landscape gardeners. They're guppies - tiny and beautifully coloured fish, just an inch or so long. Without tools or plans, they shape the environment around them, tweaking everything from the numbers of different species to the…
By Copyleft [CC BY-SA 3.0, via Wikimedia Commons As I was looking through the scientific literature the other day, I came across an article published in 1973, "The Evolutionary Advantages of Being Stupid." With a title like that, how could I not read it? In this article Dr. Eugene D. Robin…
And the #1 blog entry published thus far in 2017 discussed whether there was an evolutionary advantage to being stupid: ---- As I was looking through the scientific literature the other day, I came across an article published in 1973, "The Evolutionary Advantages of Being Stupid." With a title like…
Okay guys, if you had a choice between having a big brain or big .. er, testes .. which would you choose? A recent scientific paper reveals that as sexual selection pressures increase in promiscuous bat species, males evolve larger testes and smaller brains. But in bat species where females…