Chedderhead Charlie and Camembert Kate are Monterey Jack's parents. Cheddarhead is an adventurer in his own right. Cheddarhead loves to travel, going on trips every year and twice on a leap year, while Camembert loves adventures and travels more than Cheddarhead. She sometimes visited Monty and the Rescue Rangers. Camembert appeared in the episodes: "Parental Discretion Retired" (#08) and "A Lean on the Property" while Cheddarhead only appeared in "Parental Discretion Retired".
Cheddarhead is a mouse the same size and brown color of Monty. They also share the same nose and green eyes (though in one scene he appears to have blue eyes). He has chin-length gray hair, a gray bristly mustache, and appears to have some slight stubble. He wears a black Australian bush hat with a gray band, a long-sleeve red shirt, khaki vest, and purple fingerless gloves. He is sometimes shown with his sailor's duffle bag, which presumably contains all his possessions.
Cheddarhead is much like Monty, though to a further extreme. He is strong, loud, always ready to fight, enjoys adventures, is reckless, and prefers to jump in to a situation without planning first. While Monty has apparently learned the value of teamwork, planning, and caution during his time with the Rangers, Cheddarhead prefers to dive straight in to a situation, trusting his luck and strength to carry him through.
It is unknown if Cheddarhead has cheese attacks like Monty. However, he has a slight reaction when he first sees Gadget, presumably indicating some level of attraction.
His catchphrase is "Cheddarhead Charlie's my name. Adventure's my game."
Cheddarhead joins the Rangers on a case. While his actions do move the case forward, he also charges in without forethought. This often results in trouble and danger for him and the other Rangers. At the end of the adventure, he admits that the Rangers' methods work, but they are not his style and so he departs.
Kate is the same size and color as Monty. In her first appearance, she wears a yellow jacket and hat and a purple dress with darker purple flowers on it. She also has red lips. In her second appearance, she wears a blue shirt, a pink dress, and a captain hat.
Like her husband and son, Kate is an enthusiastic adventurer but she continues to treat her son like a baby, much to his chagrin.
Kate only appears at the end of "Parental Discretion Retired." She makes a full appearance in "A Lean on the Property," where she visits the Rescue Rangers and teams up with the group. She treats Monty like a baby and she doesn't think that her son has great ideas so she comes up with better ones. When she gets trapped by Fat Cat and Monty rescues her, she now believes that her son can do anything on his own.
- Cheddarhead apparently had not met Zipper before, or at least did not recognize him, implying that Monty and Cheddarhead had not met since Monty teamed up with Zipper.
- In this early episode, Peter Cullen voiced Monty and Jim Cummings voiced Charlie. This is a possible basis for a retcon of the change from Cullen to Cummings for Monty's voice: his voice changed as he aged.