I have a cub that is level 6, and I want her to have a mate but can’t find one, how do I get a mate..

You need to go to the main menu, tap on the change animal, and staying on the animal that you're on, there is a button at the top left of the screen that says family. You tap it and select the pup once it reaches level 10, then when it asks you if you're sure, then say yes. If you want to switch back and forth between the original mates and the child and their mate, you just do the same steps but you just tap on the mates that you want to play. I will warn you to be careful because once your child gets its own mate you cannot have them join the original pair again, and the original pair only have to be level 10 instead of 20 to get the second pup after the first pup leaves to get a mate, I made this mistake and now my female is pretty much useless for now because of how slow she is...

In a earlier version of the game, there was a glitch when you had a cub, removed it from the family, and gave birth to a cub in the same slot that it would have somthing like 9E+18 exp, almost getting it out of the den instantly(you had to feed it once first) as I called the ‘inheritance glitch’. A reason I called it that was because it had your original animal in that slot’s stats until it was at a specific level, which made it easier in earlier versions of the game to overcome this issue. It was one of the earliest versions(1.3 i think) so the game was tend to have glitches like that. That glitch has since been patched(i tried to do it but the cub was completely normal when leveling through 1/3, no weird numbers, making me sure of this)