Our last remaining rat’s age is something of a mysterious. She’s outlived not just her twin, she’s outlived the other two rats they were bonded with. She just keeps going and going and going, without any medical problems. Some breathing issues but she’s a pet rat, they all have them. No tumors, which is something new for me as a rat owner—though it seems like Colorado rats are healthier than Illinois ones—the pet rats, anyway. Not sure about the feral ones. It’s also very strange because, while she’s friendly, it’s not like she’s bonded with us.