In 1997, a forensic examiner in Berlin reported one of his more unusual cases in the journal Forensic Science International. A 31-year-old man had retired for the evening to the converted garden shed behind his mother’s house, where he lived with his German shepherd. Around 8:15 p.m., neighbors heard a gunshot from the direction of the shed.

Forty-five minutes later, the man’s mother and neighbors found him dead of a gunshot wound to the mouth, a Walther pistol under his hands and a farewell note on a table. Most of his face and neck were gone—and there were tooth marks around the edges of the wounds. A half-full bowl of dog food sat on the floor.

The German shepherd was calm and responded to police commands. On the way to an animal sanctuary, the dog vomited some of its owner’s tissue, including skin with still-recognizable beard hair.

WATCH: Why Do We Have Pets?

No one tracks the frequency of pets scavenging their expired owners’ bodies, but dozens of such case reports appear in forensic science journals over the last 20 years or so, and they’re the best window we have into a situation dreaded by pet owners: dying alone and being eaten.

I’ve reviewed about 20 of these published cases, along with a 2015 study that pulled together 63 cases of indoor scavenging. Some of the patterns are surprising, and they open up fascinating questions about why pets might be motivated to eat the dead.

Here are some of the most common misconceptions about post-mortem pet behavior and what the available forensic evidence reveals. (Also see “Exclusive: Bone-Sniffing Dogs to Hunt for Amelia Earhart's Remains.”)

It Must Have Been the Cat

Cats get a bad rap for being the most eager to eat their owners, and anecdotally, some emergency responders say it’s pretty common. When it happens, cats tend to go for the face, especially soft parts such as the nose and lips, says forensic anthropologist Carolyn Rando of University College London.

“It doesn’t surprise me, as a cat owner,” she says. “If you’re sleeping, they tend to swat your face to wake you up.” (See more about pet personalities in “Surprising Things You Never Knew About Your Cat.”)

Then again, in one case reported in 2010 in the Journal of Forensic and Legal Medicine, a woman died of an aneurysm and was found the next morning on the bathroom floor. Forensic testing revealed that her dog had consumed much of her face, while her two cats hadn’t touched her.

Among the cases reported in forensic journals, most animal scavenging involves dogs, although that’s perhaps in part because forensic scientists are more surprised by the behavior when they see it.

Hunger Hypothesis

“Dogs are descended from wolves,” says Stanley Coren, a psychologist who has written books and hosted television shows about dogs. “If we have a situation where the owner dies and there’s no source of food, what are they going to do? They’re going to take whatever flesh is around.”

In some cases, it’s clear that the animals were scavenging to survive. In one 2007 report, a Chow and a Labrador mix survived for about a month after consuming their dead owner’s body, leaving only the top of the skull and an assortment of bone shards.

Yet in the 1997 case, the German shepherd began eating parts of its owner soon after death.

“It is interesting to consider the reasons for an otherwise well-behaved pet with no motivation of hunger to mutilate the dead body of its owner so quickly,” wrote the forensic examiner, Markus Rothschild.

In 24 percent of the cases in the 2015 review, which all involved dogs, less than a day had passed before the partially eaten body was found. What’s more, some of the dogs had access to normal food they hadn’t eaten.

The pattern of scavenging also didn’t match the feeding behavior of canines in the wild. When dogs scavenged dead owners indoors, 73 percent of cases involved bites to the face, and just 15 percent had bites to the abdomen.

By contrast, canines scavenging outdoors have a well-documented pattern, opening the chest and abdomen to eat the nutrient-rich organs early on, followed by the limbs. Only 10 percent of those cases involve wounds to the head.

Bad Dogs?

It’s tempting to think that if you’re close to your dog and have treated it well, you’re off the hook if you die. (Learn more about human-dog bonding in “Your Dog Knows Exactly What You’re Saying.”)

But dog behavior isn’t quite so clean cut. None of the case studies I saw indicated any prior history of animal abuse. On the contrary, several reports noted that the owners had very good relationships with their dogs, according to friends and neighbors.

Instead, consider a pet’s psychological state: “One possible explanation for such behavior is that a pet will try to help an unconscious owner first by licking or nudging,” Rothschild writes in his report, “but when this fails to produce any results the behavior of the animal can become more frantic and in a state of panic, can lead to biting.”

From biting, it’s an easy jump to eating, Rando says: “So it’s not necessarily that the dog wants to eat, but eating gets stimulated when they taste blood.”

A Matter of Breeding

Different dog breeds have different temperaments, Rando adds, which could play a role in how they respond to an owner’s death. But many kinds of dogs turn up in forensic reports of scavenging, including lovable labs and golden retrievers.

The cases I read involved a mix of mutts as well as several hunting or working dogs. Overall, most of the dogs were medium to large, with a beagle being the smallest breed to engage in scavenging in these reports. However, larger, more powerful dogs can do more damage, so those cases might be more likely to rise to the level of note.

For instance, in three separate cases, dead owners were eaten to the point of decapitation, and they all involved German shepherds. Still, for all we know, a Pomeranian or Chihuahua would tear a head off if it could.

Rando suspects that an individual dog’s temperament might matter more—an insecure, fearful dog that regularly shows signs of separation anxiety may be more likely to move from frantic licking to biting to eating.

So What to Do?

There’s no way to guarantee that your pet won’t eat you if you die, apart from not having any pets. Even hamsters and birds have been known to scavenge on occasion.

The best way for pet owners to reduce the odds, Rando says, is to make sure you have people who will stop by if they don’t hear from you. And if you have neighbors who are elderly, sick, or vulnerable, you should check on them regularly.