It’s not a given that because you are Wiccan that you must have a familiar animal. Having a familiar is not really part of the teachings of Wicca, it’s allowed but it’s not required. Familiars were first made popular during the witchcraft trials long ago when people would accuse their neighbours of hexing them and give “evidence" that the supposed “witch" had sent their “familiar" to foul the neighbour’s milk, kill his cattle, etc.
A familiar is an animal companion who VOLUNTEERS and WANTS to help a witch to do magick and spiritual workings. It’s not something that can be forced, your animal either wants to or it doesn’t. If your pet wanders away when you’re doing a ritual, let it go with the understanding that it simply wants to be your friend, not your working partner. To tell if your pet actually wants to be your Familiar look for signs. Does he or she always want to be front and centre when you’re casting spells? Does your pet voluntarily come into your circles and hang out happily with you? If so, then it’s possible that your pet is interested in magick and is willing to be your familiar.
Animals can easily sense energy and are so good at it that they can easily move in and out of Cast Circles without harming or breaking the boundary.
Wild animals sometimes volunteer to become familiars. If a particular animal in the wild repeatedly shows up during your rituals, then it may be quietly acting as a familiar to you. Don’t try to approach the animal, simply allow it to lend its energy to you while it is present.