Michigan’s highest court has refused to reopen a decision that leaves seven chimpanzees confined at a roadside zoo, despite one justice arguing that the law should reflect current scientific knowledge.

The case first drew attention last year when a three-judge panel of the Michigan Court of Appeals rejected a habeas corpus petition brought by the Nonhuman Rights Project on behalf of the chimps held at the DeYoung Family Zoo in Wallace. The lower circuit court had already dismissed the request without a hearing, ruling that the chimpanzees were not persons entitled to such relief. The appeals court upheld that view, with Judge Matthew Ackerman writing that the animals are property under long-standing common-law principles. He cited historical authorities, including Sir William Blackstone’s reliance on the biblical account of human dominion over animals.

Undeterred, the advocacy group appealed again, asking the Michigan Supreme Court to update the common law in light of modern science. They emphasized that chimpanzees are highly autonomous and intelligent, share nearly 99 percent of human DNA, and have a fundamental interest in exercising their autonomy comparable to that of people.

The Supreme Court declined to take the case, stating only that it was not persuaded the issues warranted review. Justice Elizabeth Welch dissented, saying she would have granted leave to examine whether habeas relief should evolve with our deeper understanding of animals. She questioned whether an 18th-century jurist’s reading of Genesis remains a solid basis for 21st-century Michigan law and pointed to evidence that chimpanzees can think, feel, love, grieve, and yearn.

Judge Ackerman had already anticipated the difficulty of drawing a line once courts begin weighing animals’ mental and emotional capacities, noting that no clear exception exists for intelligent animals and that such an approach lacks a natural stopping point.

The Nonhuman Rights Project has pursued similar cases involving chimpanzees and elephants in other states but, so far, has not succeeded in securing their release and, hopefully, they never will. The Michigan ruling is the latest setback in that ongoing effort.