Parasite gives wolves what it takes to be pack leaders

Wolves infected with a parasite that commonly infects cats are more likely to become leaders of the pack or strike out on their own. In a data set spanning 27 years, wolves in Yellowstone National Park that were infected with Toxoplasma gondii were 46 times more likely to become pack leaders and 11 times more likely to start a new pack than were uninfected animals.