The costumes are coming off, the shackles are being unlocked and the boxcars are opening. After more than 130 years, the Ringling Bros. and Barnum & Bailey circus will retire its elephants, sending them to a conservation center in Florida.

As a child, my favorite movie was Disney's "Dumbo." There is a heart-wrenching scene where Dumbo is being cradled by his mother, who is chained inside a boxcar. That indelible scene stuck with me, and now, as an animal-rights advocate, I am overjoyed by this recent news.

There is a deep history of use and exploitation of elephants in circuses. In 1882, P.T. Barnum, a showman and businessman, purchased Jumbo, a 12-foot-tall African elephant, from a London zoo and shipped him across the Atlantic to New York to be featured in the Barnum & Bailey Circus, which later merged with the Ringling Bros. Circus.

Over the years, Ringling amassed a menagerie of elephants — it now owns 53 — and forced them to perform tricks such as balancing on their hind legs with their front legs perched on top of one another, forming a sort of elephant conga line, all for paying customers.

When they are not performing, the elephants are chained and shipped around the country in boxcars.

Elephants are some of the most cognitively complex and social nonhuman animals that we know of. They are adept tool users, self-aware and cooperative problem-solvers. In the wild, elephants walk as many as 40 miles each day. They form deep social bonds and live in cohesive family groups of sometimes upward of 100 members.

Elephants frequently display empathy; for instance, they have been observed feeding others who are unable to use their own trunks to eat. They can communicate over long distances by producing vibrations that are inaudible to humans.

Elephants possess an understanding of death and have been observed engaging in mourning behavior.

A circus environment cannot replicate the rich array of experiences and social life that the wild affords them.

After years of mounting pressure, Ringling has succumbed to public protest. Feld Entertainment, Ringling's parent company, said it is "adapting" to the changing climate and "mood shift" among its customers.

While this is a major victory for activists as well as consumers who are rightly opposed to the use of elephants in circuses, the fact that Ringling was able to exploit elephants for this long is a perfect example of how our legal system has failed nonhuman animals.

The reason circuses have been able to exploit elephants is that the law views elephants, and every nonhuman animal on earth, as property. The law, at its foundation, classifies all nonhuman animals as commodities that can be bought and sold and treated in almost any way imaginable. Our animal-protection laws are notoriously weak and have many exemptions.

Unless the law starts recognizing these extraordinary animals as something other than objects, they will forever be at the mercy of their "owners" to decide to do the right thing. It's a risk, and a risk that isn't paying off for most animals.

That's why something else is needed — a solution that addresses the core problem, that nonhuman animals are classified as property. A solution that won't leave animals at the mercy of companies to realize (or not) that keeping such extraordinary animals in captivity is inexcusable. A solution that takes into account the kind of beings that elephants and other animals are.

My colleagues and I at the Nonhuman Rights Project have been strategizing for years to come up with a solution — and now we have.

In 2013, we filed our first lawsuits in which we argue that certain nonhuman animals should no longer be classified as "legal things" but instead as "legal persons" who have the capacity for basic fundamental rights. Our lawsuits were filed on behalf of four chimpanzees in New York.

We are operating under common law, rather than statutory law. Common law is inherently flexible, and common-law judges are supposed to take into account and align the law to changing public morality and scientific understanding.

Just as Feld is "adapting," we at the Nonhuman Rights Project believe that common law must adapt to the new scientific evidence and changing attitudes about certain nonhuman animals.

As our chimpanzee cases make their way through the New York courts, we are focusing our next lawsuit on captive elephants. We will ask a court to recognize their legal right to bodily liberty so that they can be transferred to a sanctuary where they can — as a matter of justice — live the kind of life that is as close as possible to what they would experience in the wild.

Unfortunately, Ringling won't retire all of its elephants until 2018. Even before that, we hope a court of law will set legal precedent that certain nonhuman animals have basic rights and are no longer anybody's to own.

Natalie Prosin is the executive director of the Nonhuman Rights Project. She wrote this article for the Washington Post.