I imagine that they have lifespans, because we do see older ones. But out in the field they cant. They faint just like regular hunters. When you're attacking them in the field they just kinda dig and run away.

As far as I know, the other cats won't attack you and vice versa. 

Maybe seems like a weird question, but asking for my girlfriend who kind of wants to pick the game up but also cried when she saw me attack a felyne in Monster Hunter Tri back in the day (she really really loves cats.)

Can felynes die in MHW?