It depends, i have a male Jack russell aged 7 and at first we introduced him to a older greatdane..... Didn't get along so we where worried about getting one!, but we bought our greatdane when she was a puppy!, it took a couple days but they got along (:
no
That depends on your dog's temperment somewhat. The rule of thumb is to get the opposite. If the older dog is a male I would definitely get a female (make sure there is no accidental breeding though!). Two males are less likely to get along with each other. If the older dog is a female you may still want to get a female new dog, because females don't like to put up with young male dog antics. However, not all females get along with other females.
No, to mate there needs to be a female and male involved
If you mean 2 other female bettas, probably not. Females generally are non aggressive and do fine with other females.
Yes rabbits and cats can get along with each other if they are introduced at an early age. Pretty much any animals can get along if they meet when they are young.
Gerbil mothers should be kept either alone with their pups or with the father and the pups. NEVER put two females together if one is pregnant or nursing, as the other female will most likely get defensive and kill the litter. This goes even for gerbils who get along really well. The only instance you can keep two females in with a litter is if the other pup is a female from the previous litter.
In a Pedigree the circle represents a female. Though on other sites it says other wise. Any other answer is scientifically incorrect.
The female gerbil CAN accept a new female gerbil, but it totally depends on the characteristics of the two gerbils. If one is friendly, and the other is hostile and territorial, they don't go together. You just have to try it out to see what works. some females get along but all of them.
Yes
Are females who are just LIKE ANY OTHER FEMALE!
No , the porcupines don't get along because the males fight over the females.
I think. I have two female guinea pigs and they get along fine.