Brain size determines whether fish like to hunt or wait for dinner

A new research has revealed that the brain size of fish determines their eating habit, whether they want to hunt down their prey or wait for it to come.

 

Professor Rob McLaughlin, a researcher from the University of Guelph, has discovered that foraging behaviour of brook trout is related to the size of a particular region in the fish’s brain.

 

“We found that the fish that swim around in the open in search of food have larger telencephalons than the fish that sit along the shoreline and wait for food to swim by in the water column,” McLaughlin said.

 

“This means there is a correlation between foraging behaviour and brain morphology,” he added.

 

The telencephalon is a brain region involved with fish movement and use of space.

 

“It’s responsible for a fish’s ability to swim around to different places and remember landmarks in the environment so they don’t get lost,” he said.

 

“These are young fish that have been foraging for less than a month, and we are already seeing a difference in the propensity to take risks and move around. This made us wonder if these differences were significant biologically,” he added.

 

McLaughlin and researcher Alexander Wilson collected these two types of fish from the Credit River near Toronto and measured the size of their telencephalon region.

 

They also measured the brain's olfactory bulb to ensure that the active foragers did not simply have larger brains overall than the sedentary fish.

 

“We found there was no significant difference in the size of the olfactory bulb between the two types of fish. We picked this part of the brain because trout are visual feeders, so the olfactory bulb is not tied to foraging, and it’s also an area that’s near the telencephalon,” Mc Laughlin said.

 

The finding has been published in the journal Behavioral Ecology and Sociobiology.