Stories of exotic animals on planes can cause some to view emotional support animals negatively. But for those in need, they do make a difference.

In October 2016, a duck wearing red shoes and a Captain America diaper boarded a plane from Charlotte to Asheville, North Carolina.

The duck’s name was Daniel Turducken Stinkerbutt and he was flying courtesy of another passenger, Carla Fitzgerald, as her emotional support animal (ESA).

Photos of Daniel in the airplane cabin went viral shortly after a fellow passenger posted them on Twitter.

While Daniel may have been the cutest little duck in red shoes to ever ride an airplane, stories like this and the growing popularity of emotional support animals has become a major point of contention with airlines.

In recent years, animals on planes have gone from the stuff of quirky social media gawking to full-blown policy debacle.

The problems don’t stop there either.

Housing and colleges across the country are also struggling to deal with an unforeseen boom in demands for accommodations related to emotional support animals.

However, as the need appears to be increasing, the general public, businesses, and even legislators can find the topic confusing.

Are emotional support pets really necessary? What do they do? Where are they allowed to be, and which species can qualify as an ESA?

Here’s everything you need to know about the role of emotional support animals.

Emotional support animals are not pets. They provide therapeutic benefits to people with a disability.

However, they’re uniquely different from service animals, which are defined by the Americans with Disabilities Act (ADA) as dogs (and in some cases, miniature horses) that “are individually trained to do work or perform tasks for people with disabilities.”

Examples of these tasks include guiding someone who is blind, pulling a wheelchair, or alerting someone with diabetes that their blood sugar levels have dropped.

In cases of certain severe psychiatric disorder, such as post-traumatic stress disorder (PTSD), service animals can also be trained to help calm down their owners.

ESAs on the other hand require no training whatsoever and their therapeutic value is derived simply from being with their owner.

“For someone with depression, having a support animal can give the person hope and a sense of purpose,” Jessy Warner-Cohen, PhD, MPH, a health psychologist at Long Island Jewish Medical Center, told Healthline. “For a person with anxiety, the act of petting an animal can also be of benefit.”

Research indicates that animals can help in alleviating the symptoms of certain psychological issues, including PTSD and overall stress. However, the benefits and potential of ESAs still requires more research and is only beginning to be understood.

“It should be of note, though, that the use of animals as part of the therapeutic process is not considered an evidence-based practice and has little support in the scientific literature. It is used more on a case-to-case basis depending on the specific circumstances of an individual,” said Warner-Cohen.

Nevertheless, anecdotal evidence supporting ESAs is powerful.

Healthline spoke with Matt Z., 31, of Long Beach, California who has been living with his dog and ESA Maximus for four years.

Matt has been diagnosed with borderline personality disorder, but also lives with depression and social anxiety.

“He’s really worked wonders,” said Matt of his white Shi-Poo, which he’s owned since he was a puppy.

Matt will often do counting or breathing exercises when he’s feeling stressed and says that petting Maximus, “helps slow me down.”

“The question that arises is whether the impact of this animal for this person goes above and beyond those of generally having a pet,” said Warner-Cohen.

Believe it or not, ESAs have had legal precedence since the late 1980s.

According to the Fair Housing Amendments Act of 1988, the United States Department of Housing and Urban Development (HUD) considers “assistance animals,” which includes both ESAs and service animals a “reasonable accommodation” for an individual seeking housing.

That means that individuals who are able to furnish documentation — and in some cases documentation isn’t even required — such as a letter from a doctor explaining their need for an ESA, then they can’t be turned away, even in housing with “no pets” policies.

Also, landlords can’t charge for additional costs like pet deposits.

However, the Fair Housing Amendments Act is also notoriously vague. It doesn’t specify any restrictions to breed or even species that an ESA can be, unlike the ADA which explicitly states dogs and miniature horses.

“It’s a case by case test and I think that just does make it a burden for landlords because anybody can argue anything. I’m sure someone could argue that their alligator is the best pet and does not present risk of harm or safety to the other residents, but is that reasonable?” said Rebecca Wisch, associate editor and staff attorney for Animal Legal and Historical Center, a digital law library based out of Michigan State University College of Law.

To complicate matters further, ESAs and service animals are subject to different policies aboard airplanes.

Wonder why people are boarding planes with ducks, pigs, and even peacocks as their emotional support pets?

Under the Air Carrier Access Act (ACAA) neither ESAs or service animals are defined by breed or species. Instead, whether or not an animal can fly in the cabin largely depends on their size and whether or not they pose a threat to other passengers.

These incidents are largely handled on a case-by-case basis by airlines rather than through a uniform policy, although airlines aren’t required to allow certain types of animals including snakes, rodents, and spiders aboard.

Despite HUD policy dating back to the late 80s, experts agree that an unprecedented surge in demand for ESAs has only truly occurred within the last 5 to 10 years.

In 2013, the HUD released a policy statement reminding landlords about their obligation to provide assistance with disabilities, particularly with respect to assistance animals.

Wisch said the release of that statement, combined with new ways to obtain ESA letters from doctors online, created a watershed moment.

“Hand in hand that policy document combined with the digital age has just created something unforeseen,” she said. “Sometimes the tail wags the dog.”

Traditionally to have an ESA, a doctor, therapist, or mental health expert must write a letter describing what disability or psychological problem an individual has and why they’re recommending an ESA as an intervention.

However, in the digital era, the process has been streamlined through technology, and sometimes compromised in unscrupulous gray markets as well.

“The explosion of e-commerce and the internet is new. I think it’s an issue of technology and entrepreneurs moving faster than government regulation,” said Wisch.

Websites like can quickly set customers up with an appointment with a mental health professional and provide a one-year ESA travel letter for $149.

Another website sells ESA letters in an online store alongside American flag patches that say “disabled veteran,” and identification cards for your animal.

Despite looking “official,” neither registration certificates nor ID cards for ESAs are regulated nor required by any federal agency.

“There is no certification. There is no registry,” said Wisch.

Many argue this is the reason so many are able to abuse the system.

“Many of these online mental health folks never meet the client. So, you answer an online questionnaire, someone reviews that, and then 100 percent of the time they give you the letter. They aren’t going to turn you down, because if they turn you down they don’t get paid. So, there’s a conflict of interest there,” said Phyllis Erdman, PhD, professor in counseling psychology and executive associate dean of academic affairs, college of education at Washington State University.

Erdman and her colleagues have studied the rise of ESAs around the country and particularly the effect they’re having on college campuses.

Erdman is the coauthor of a new study in the Journal of College Student Psychotherapy on the response of colleges to growing demand for ESAs.

She and her fellow researchers created an online survey about ESAs and polled university counseling centers at 248 universities across the United States.

Much like airlines, colleges appear ill-equipped to handle requests for the animals, and few have any policies in place to deal with them.

Erdman told Healthline, “Here at our university it’s gone, in the last seven or eight years, from two to three requests to over 90. Not only are they not able to handle the requests as far as writing the letters, but the housing directors are struggling with the accommodation requests as well.”

Universities have been hesitant to set firm guidelines related to ESAs because they’re worried about finding themselves on the wrong side of a lawsuit.

And they have reason to fret: denying housing because of an ESA has resulted in six-figure lawsuits against universities and apartment landlords.

“Colleges are confused,” Erdman said.

“As assistance animals become more prevalent in society, there appears to be a parallel increase in the frequency of allegations of misrepresentation or fraudulent representation of animals as assistance animals,” wrote the authors of a 2017 study on public perceptions of service animals and ESAs.

While they conclude that in general most people don’t feel that individuals are abusing the system, they maintain that high-profile incidents in the media reflect negatively on ESAs and drive the views of a “small, but vocal minority.”

Nonetheless, every expert contacted by Healthline said that change at the federal level in harmonizing training and regulation of ESAs would be a benefit not only to public perception of these animals as legitimate therapeutic interventions, but would also allow for more confident decision making from universities, landlords, and airlines.

“I think if there was more regulation of what is expected of these animals, what kind of training, and the benefit of them, then I would think that at the federal level that these entities could come together and have a little more common understanding. Talk to each other and make one common ruling,” said Erdman.