Children from Harry Potter that are selected by the Sorting Hat to be in Slytherin are chosen to be put in their selected house by their personality and thoughts. One huge thing that helps pick which house they go into is how they think but once selected you can tell what type of person they are. If you are put into Slytherin you are generally brave, ambitious, strong leaders and very competitive. The one trait that Slytherin children or members have is that they can be quite cunning and mean at times.
Each child has a different pet that could be a bird such as an owl as you probably already know or a different type of fish, reptile or different kinds of rodents. An owl is the most popular and are normally the pet that are known to deliver letters to you or friends around you.