DENVER (AP) — Missy, Kimba, Lucky, LouLou, and Jambo have lived in Colorado Springs for decades in the elephant exhibit at the Cheyenne Mountain Zoo. Now an animal rights group is trying to release the elephants from what they say is essentially a prison for such highly intelligent and social animals known to roam for miles a day in the wild.

Colorado’s highest court will hear arguments Thursday on whether the older African female elephants should be legally able to challenge their captivity under a long-held process used by prisoners to dispute their detention. The animal rights group NonHuman Rights Project says the animals are languishing while “unlawfully confined” at the zoo, and wants them released to an unspecified elephant sanctuary.

“They are suffering immensely and unnecessarily. Without judicial intervention, they are doomed to suffer day after day, year after year, for the rest of their lives,” a lawyer for the group, Jake Davis, said in a May brief submitted to the Colorado Supreme Court.

The main legal issue is whether or not the elephants are considered persons under the law, and therefore able to pursue a petition of habeas corpus challenging their detention. The NonHuman Rights project argues that legal personhood is not limited to humans.

The lawsuit is similar to an unsuccessful one the group filed challenging the confinement of an elephant named Happy at the Bronx Zoo in 2022. New York’s Court of Appeals ruled that Happy, while intelligent and deserving of compassion, cannot be considered a person illegally confined with the ability to pursue a petition seeking release.

The New York ruling said giving such rights to an elephant “would have an enormous destabilizing impact on modern society” and change how humans interact with animals.

The Cheyenne Mountain Zoo says moving the elephants and potentially placing them with new animals would be cruel at their age, potentially causing them unnecessary stress. It says they are not used to being in larger herds and, based on its experience, they do not have the skills or desire to join them.

In a statement ahead of Thursday’s hearing, the zoo claimed the NonHuman Rights Project isn’t concerned about the elephants but is just trying to create a judicial precedent that would allow the captivity of any animal to challenged.

“We hope Colorado isn’t the place that sets the slippery slope in motion of whether your beloved and well-cared-for dog or cat should have habeas corpus and would be required to ‘go free,’ at the whim of someone else’s opinion of them,” it said.