I have found out something quite interesting.

We have two Jack Russell Terriers. Half brother and sister. (Same mother). We also have two horses, one mare and one gelding.

I have closely observed that the females tend to exhibit the same behavior, no matter what species they are.

Things like, for example, some days they could care less that you even exist, and other days you are their best friends and can do no wrong. Where as, the males always exhibit "your my best friend" attitude all the time.

As an example of this, when I come into the house for the evening, both dogs will greet me, as dogs always do. But the female may "disappear" somewhere in the house for the rest of the night. The male dog is always close by watching us, and will follow all over the house, keeping close. The female, maybe, maybe not.