Yes, all bishops, including cardinals and the pope wear mitres.
They have miters and crosiers.
Cardinals typically wear a red skullcap called a zucchetto on their head. It is a traditional head covering for clergy in the Catholic Church, including cardinals.
The box-like caps are called biretta ( singular birettum) Bishops wear purple ones. Cardinals wear red. There is a red brimmed hat the cardinals may wear called a galero. The skullcap worn by bishops, cardinals and the pope is called a zucchetto.
Priests rarely wear the zucchetto, or skull cap. It is primarily worn by bishops, archbishops, cardinals and the pope. Each being distinguished by the color - bishops and archbishops wear violet, cardinals red and the pope white. A priest would wear black.
St. Nicholas was a bishop and red was the color of bishops at the time. Today, red is the color of cardinals and violet the color of bishops.
Yes and no. All cardinals are bishops and all cardinals under age 80 are eligible to vote in the conclave. However, not all bishops are cardinals.
There is a college of cardinals but not a college of bishops.
The ones wearing purple are not cardinals, they are bishops.
Bishops that elect the pope are called cardinals.
Cardinals or bishops do not wear a yarmulke, they wear a zucchetto, which is similar head cover. The color distinguishes the rank: black (rarely worn) is for priests, violet for bishops, red for cardinals and white for the pope. Some say it originated during the Middle Ages when churches had no heat. Many of the clergy worn a tonsure - the top of their head was shaven. The zucchetto help keep their head warm in the winter.
They don't, Catholic Cardinals wear a cardinal red zucchetto - which looks an awful lot like a "skull cap" but isn't. Actually, all clerics may wear a zucchetto, priests wear black, bishops wear purple or violet, Cardinals wear red, and the Holy Father wears white.
Cardinals elect Popes, but they are not necessarily bishops.