Whether zoos should keep animals confined is a hotly debated topic, with both the public and animal experts having varying opinions.

Supporters tout the valuable research and conservation efforts of zoos, which work with endangered species and serve as more than just a place to see the monkeys on a Sunday afternoon.

For instance, the San Diego Zoo received two female Chinese alligators from a zoological park in Florida in early July and wants to start breeding the critically endangered species if they can get a male Chinese alligator next year. The alligators’ numbers have dwindled due to hunting and their habitat along the Yangtze River in China has been wiped out by the building of dams.

Others, like Jane Goodall, the renowned chimpanzee expert and conservationist, also believe that the wild is not always the right fit for certain animals. In a 2011 interview with the Houston Chronicle, Goodall said that many chimpanzees live in forests that are being cut down, or “they can be hunted as they are across large areas of Africa… So if you’re a chimp, your best choices may be to be in a secure place in the wild, or a really good zoo… This kind of idea that any kind of wild is always good is not right.”

But there are those that disagree with the idea of keeping animals confined. Ric O’Barry, a former dolphin trainer for the TV show Flipper, is now an activist who doesn’t see any educational benefit to keeping the animals in captivity or in entertainment shows. In a 2012 interview on Canada’s CBC Television, O’Barry said: “We’re teaching children that abusing nature is ok and that dolphins are performing circus clowns and that’s all they are… We’re teaching kids all the wrong stuff.”

Orcas, or killer whales, have also long been used in entertainment shows, and the ethics of keeping them in captivity came to the forefront in 2010 when a trainer was drowned at Orlando’s SeaWorld theme park by a whale named Tilikum.

A former trainer Jeff Ventre told Wired Science that the 2010 incident and another fatal attack were “a direct byproduct of the stress associated with captivity”. He added, “killer whales don’t attack humans in the wild.”

Travellers who want to visit the most ethical zoos can check to see if a particular animal park is a member of the Switzerland-based World Association of Zoos and Aquariums (WAZA). Member zoos must sign a code of ethics that says the aim of all zoo professionals is to assist “in achieving the conservation and survival of species”. Members must promote biodiversity and animal welfare as well as support research and public education programs.

Travellers can also search for particular zoos via regional chapters of the group, such as the Association of Zoos and Aquariums in the United States, which has issued 224 accreditations. The European Association of Zoos and Aquaria also promotes conservation and quality among its 345 members.

What makes for an ethical zoo? Conservation and good animal care, of course, which means “animals should be able to show as much of their natural behaviour as possible”, said Gerald Dick, executive director of WAZA. “Good zoos have enrichment programmes in place so the aforementioned can be facilitated.”

Lori Robertson writes the Ethical Traveller column for BBC Travel. You can send ethical dilemmas to bbcethicaltravel@gmail.com.