A Wolfpack may have had many as 20 wolves by three weeks of age Wolfpack are mostly able to play. Most packs are led by an adult male and a female. The average size of wolf leader is around four pops. What type of evidence does the author use to develop an argument.

The author uses empirical evidence to develop their argument. They state specific facts about the number of wolves in a wolfpack at three weeks of age and the average size of wolf leaders, which suggests a pattern or trend in wolf pack behavior. This evidence helps to support the author's claim that wolf packs are mostly able to play and are led by an adult male and female.