Colo. Rev. Stat. § 15-5-408
Subject to this section and section 15-5-409.5, a trust for the care of designated domestic or pet animals and the animals' offspring in gestation is valid. For purposes of this section, the determination of the "animals' offspring in gestation" is made at the time the designated domestic or pet animals become present beneficiaries of the trust. Unless the trust instrument provides for an earlier termination, the trust terminates when no living animal is covered by the trust. A trust instrument must be liberally construed to bring the trust within this section, to presume against the merely precatory or honorary nature of its disposition, and to carry out the general intent of the settlor. Extrinsic evidence is admissible in determining the settlor's intent. Any trust pursuant to this section is an exception to any statutory or common law rule against perpetuities.
C.R.S. § 15-5-408