Happy the Asian elephant has been living at the Bronx Zoo for more than 40 years.

She’s 47 years old and has been living alone since 2006, separated from the zoo’s two other elephants ever since a fight led to bad blood.

So is Happy happy? It depends on whom you ask.

The zoo has said many times that Happy is quite content. But an animal rights group has described the situation quite differently, saying that the elephant is being unlawfully imprisoned. So it’s suing the zoo to set Happy free.

The Nonhuman Rights Project is a nonprofit organization that defends “nonhuman animals.” It’s seeking to get Happy — and three other elephants and a handful of chimpanzees — the same legal protections as humans.

It filed a petition on Happy’s behalf.

The group said that by keeping Happy in captivity, the zoo is depriving the elephant of her liberty. Instead, it wants Happy to be moved to an elephant sanctuary where she can make new friends.

The Bronx Zoo’s director called the group’s claims “ludicrous” in a statement. He said the organization was “exploiting the Bronx Zoo elephants to advance their own failing cause.”

The zoo has issued several statements in recent years saying that Happy is not lonely. In 2016, Mr. Breheny said that Happy has “tactile and auditory” contact with her elephant frenemies.

Even so, Happy’s living conditions have been making animal-rights activists somewhat sad for years. Until 2002, Happy hung out with a fellow elephant named Grumpy (yes, really).

Then, the duo was relocated to an enclosure with two other elephants, Maxine and Patty. Those two elephants charged at Grumpy, who never recovered from the injuries and died. Happy was given another pachyderm partner, Sammy, who died in 2006.

A week later, the Bronx Zoo announced that it would no longer acquire new elephants. Which meant no new roommate for the hapless Happy, who has been flying solo ever since.

Happy’s case isn’t the Nonhuman Rights Project’s first brush with the courts. Also on its client list are three elephants from Connecticut and four chimpanzees. But the group has not yet had success in court for any of the animals it represents.