Yes, you can leave a will, in the form of a trust for your pets. This is generally called an honorary trust. For an honorary trust to be valid you must provide financial means to take care of an animal for up to twenty or so years. You must also name a beneficiary (the pet), show your intent to create a trust, select a trustee (the person that will make sure your trust is followed out in the best interests of your pets or as you see fit), and provide the means for the pet. Courts will uphold these honorary trusts in court. There are in fact many cases involving honorary trusts. The Animal Legal & Historical Center has a list of cases that indicate how courts have protected and validated trusts concerning a pet as a beneficiary.
It is important to note that the person you pick as your trustee either has the sole responsibility for the well-being of the animal or has responsibility to check up on whoever you give such a responsibility of taking care of your pet. You must make sure that you put everything you know about the animal down accurately. You should also make sure the means for the animal are properly accounted for. You can be as specific as you want and name specific food the animal can and can not eat, how many walks a day etc. Or you can be as open and nonchalant as you want.
These honorary trusts came about in the 1980’s and you even have heard of some famous cases where the owner of an animal put asides a few million dollars, that’s right real hard cold cash for the care of a domestic animal companion. As we mentioned earlier these have been held up to be valid. Some owners have even given all their wealth to a pet instead of their own family members! Of course, we highly recommend that you consult with a wills and trusts attorney before making a trust for your pet. Honorary trusts will likely be valid if you attempt to do it through a will, but it is best you consult an attorney before doing so.
If you have further questions regarding wills check out our section on them!