In the Scottish Lowlands town of Dumbarton, there's an old stone bridge all the locals know about. It's called Overtoun Bridge, and it's the place where dogs go to die.
"The dogs commit suicide," Lisa Hamilton, a local from a neighboring town, told Mic. "People have theories of why, but I have no idea personally."
While theories abound, nobody knows for sure what motivated dozens of dogs over the last half-century to jump from the ivy-coated bridge to their deaths on the rocks below.
What is known, however, is that animals dying by their own hand — or paw or beak or flipper — is a phenomenon that has been widely documented since at least the mid-19th century. In 1847, Scientific American published a brief account from the island nation of Malta titled, "Suicide by a Gazelle."
"A curious instance of affection in the animal, which ended fatally, took place last week at the country residence of Baron Gauci, at Malta," the magazine wrote. "A female gazelle having suddenly died from something it had eaten, the male stood over the dead body of his mate, butting every one who attempted to touch it, then, suddenly, a spring, struck his head against a wall, and fell dead at the side of his companion."
While the magazine's more modern editors leapt over themselves to contextualize the event in a 2011 blog post, speculating the male gazelle was suffering from "neurological damage," the specter of deliberate animal suicide has continued to linger.
"A female gazelle having suddenly died from something it had eaten, the male stood over the dead body of his mate ... then, suddenly, a spring, struck his head against a wall, and fell dead at the side of his companion."
Today, stories of whales intentionally beaching themselves, bears locked away in grim Chinese bile farms killing their young in seeming acts of mercy or dogs mysteriously leaping from old stone bridges continue to crop up, and the implications remain as unsettling as ever.
Can pets — the dogs, cats and other animals we love — commit suicide? It's a dark question, and the answer is far from clear.
Animals and mental health
Widely undisputed is the presence of mental illness in animals. A broad selection of animal experts told Mic animals invariably experience a wide range of emotional and mental states, and the psychology of animals can be arrestingly human.
Few have studied the question more than Nicholas H. Dodman, a professor and program director at the Animal Behavior Department of Clinical Sciences at Tufts University School of Veterinary Medicine.
"You don't need to be a scientist or a veterinarian [to identify mental illness in animals]," he told Mic, adding that from a diagnostic perspective he had seen "pretty much everything" with the possible exception of schizophrenia.
"We have seen anxiety disorders, of course. One of the classic ones in dogs is separation anxiety, which also occurs in children. We see fears and phobias including PTSD [and] compulsive disorders. We've seen autism."
That's right... autism.
While critics might argue that scientists like Dodman have been taken in by anthropomorphism, or the act of ascribing human-like characteristics unto animals, Dodman was adamant the claims are supported by the facts, pointing to his own research as evidence.
For a study published in Translational Psychiatry, Dodman and his colleagues looked at atypical "tail chasing" behavior in bull terriers and compared it to behavior often associated with autism spectrum disorder. The team concluded that the affected dogs and people both exhibited higher levels of the amino acid neurotensin and corticotropin-releasing hormone.
Treating mental illness in pets
Not only do pets suffer from many of the same mental problems as humans, treatment for such ailments can also be surprisingly similar.
Sometime last year, Cooper, a 5-year-old border collie/pit bull mix, started to become antsier than usual. "I could tell something was up," his owner, Atlanta X-ray technician Jim O'Malley told Mic. "He started nipping at people, becoming aggressive with anyone coming around me."
When Cooper began to suffer from gastrointestinal troubles, his vet suggested fluoxetine, popularly branded as Prozac. O'Malley offered his own diagnosis: "I think he's OCD, somewhat."
Whether it's Prozac or Xanax or something else, medicating our pets with the things we use to treat ourselves is becoming increasingly common.
In 2007, Eli Lilly and Co., the drugmaker behind Prozac, had the drug approved by the Food and Drug Administration for use in animals under the name Reconcile, but its use as a treatment is much older. "My first national television appearance was ... in  discussing pets on Prozac," Dodman said.
Indeed, the esteemed doctor of animal maladies broached the subject during an episode of the Michael Moore-produced television show TV Nation, telling an interviewer he had prescribed the drug hundreds of times to animals, and that its use was "increasing exponentially."
"These guys are really sick," Dodman said on the show, when describing a litany of destructive canine behaviors linked to poor mental health symptoms including "flank biting" and "self mutilating syndrome."
"They start spinning in circles, barking, yapping, chasing their tails," he added. "Some of them bite their tails off."
O'Malley spoke of rapid and noticeable results once Cooper started a Prozac regimen. "I think they are just like people," he said, adding that the drug will likely be a permanent part of Cooper's life. "I wouldn't take him off it. I see no reason to."
For those looking for a more holistic approach, there is also the cottage industry of pet therapists, behaviorists and "whisperers" made famous by the National Geographic Channel's Dog Whisperer.
In New York City, the undisputed home of the world's most neurotic people, the field has found a natural habitat.
"The media kept calling me the 'cat shrink,'" Carole Wilbourn, who described herself as a "feline behaviorist," told Mic. "I deal with behavioral issues that many veterinarians cannot resolve."
Wilbourn, known simply on her website as the Cat Therapist, has been treating the city's felines professionally since 1973 when she helped launch a cat hospital. On her blog, she lists a litany of case studies, often with suggestions or details of her interventions.
In one case, Wilbourn Skyped with a pregnant woman in Dublin whose cat had taken to uncontrollable wailing. "The cat sensed that she was pregnant," Wilbourn said. To rein in the caterwauling, Wilbourn suggested a broad approach. "I told her how she could make the cat feel more comfortable, [like] when she spoke about the baby to include the cat's name, so the cat could be on the same page."
The sage advice, however, doesn't come cheap. For one-hour house calls with a phone follow-up, Wilbourn charges $365. Phone or Skype sessions like the one in Dublin are $165. More complex and customized arrangements are negotiated on a case-by-case basis. The steep financing bears more than a passing resemblance to the fault lines of psychiatric treatment for humans, especially among children, wherein the more privileged can afford personalized behavioral therapy, while the underprivileged are shoved quick-fix drugs like Adderall.
For Wilbourn, there are no quick fixes, with treatment usually entailing therapy sessions and a holistic approach that rarely calls for straight pill popping. "You treat the whole cat," she said. "It's not usually good to do a quick fix. A quick fix would just be a psychotropic or anti-anxiety drug."
"We see fish, we see amphibians, large snakes, alligators," Lorelei Tibbetts, a veterinary nurse and manager of the Center for Avian & Exotic Medicine New York City, told Mic. "Kinkajous, pet skunks, hedgehogs."
While the Internet is inundated with stories of dogs with PTSD or any one of the many articles that have documented Wilbourn's work with cats, comparatively little has been said about what to do with the unusual pets suffering from mental illness.
The vets at the center, which bills itself the only practice of its kind, are trained to do exactly that. Dogs and cats, the bread and butter of the animal wellness industry, are not permitted.
Tibbetts and her staff are replete with horror stories proving dogs and cats have no monopoly on mental illness and its self-destructive symptoms. "I've seen birds eviscerate themselves," she said. "I've seen rodents chew their limbs off, their feet, their legs. I've seen Sugar gliders devour their testicles and penis." Birds, especially parrots, said Tibbetts, were the worst. "They are the most frequent ones we see for feather destructive behavior, self-mutilation," she said.
A Huffington Post report told the story of King O, a cockatoo (pictured below) that suffered a nervous breakdown after the death of his owner and began pulling out his own feathers with his feet. (According to the story, King O is, indeed, on the mend.)
Tibbetts said it would be a mistake to assume that mental illness was merely for those animals that outwardly expressed symptoms, and not the more stoic species like reptiles, fish and amphibians. The animals "absolutely feel pain. It's just different," she said. "They don't manifest mental illness in the same way that a highly intelligent animal like a bird would, [but] there is no question that they suffer."
In some cases the causes for stress among these animals are much the same for dogs, cats and people, the loss of loves ones, a negligent home environment or a traumatic event. Other times, they arise from the unnatural experience of being kept in captivity.
Turtles are "physically able to survive living in a dark box in a child's bedroom for 20 years until a kid goes off to college. No, they don't mutilate themselves, they don't display mental illness, but I can guarantee you things aren't OK in the world of that box turtle."
Can animals commit suicide?
Animals can suffer from mental illness and they can commit destructive behavior against themselves as a result of that illness. That behavior can result in death. But does this constitute suicide? Experts are divided.
To Dodman, that's a definitive "no." "I just don't believe it," he said, adding that suicide requires an ability to "ponder," which he doubts even the most intelligent animals are capable of. "There's a thing called abstract thought, and I don't really know they are capable of this."
Wilbourn was inclined to disagree with Dodman — at least for cats. "They can lose the will to live," she said. "If they lose the will to live, they are not going to eat, they are going to withdraw."
Barbara King, a professor of anthropology at the College of William and Mary in Virginia, charted a middle course, saying that in some ways, the question was unanswerable with our present levels of understanding. "The problem that I have as a scientist is that we have to understand intent to understand suicide," she told Mic. "I'm a little bit stuck on the question of how we could get that."
Still, King, the author of How Animals Grieve, which hits on the subject, did not reject the idea entirely. "I don't think it's outside the realm of possibility," she said, adding that a better focus of inquiry would be how to reduce the conditions that lead to mentally unstable behavior.
So go home and give your dog or cat or skunk a hug. They need it, just as much as you do.