Scientists at the University of Exeter in England and Texas A&M University found when fish fight over food, it was personality, rather than size, that determined which would be victorious.
The findings, published in the journal Behavioral Ecology and Sociobiology, suggested when resources were in short supply personality traits such as aggression could be more important than strength when it came to survival.
Dr. Alastair Wilson of the University of Exeter said small fish were able to do well in contests for food against larger fish provided they were aggressive. Regardless of their initial size, it was the fish that tended to have consistently aggressive behavior -- or personalities -- that repeatedly won food and as a result put on weight.
"We wondered if we were witnessing a form of Napoleon, or small man, syndrome," Wilson said in a statement. "Certainly our study indicated small fish with an aggressive personality were capable of defeating their larger, more passive counterparts when it came to fights over food. The research suggested personality can have far reaching implications for life and survival."