With The Walking Dead's fourth season premiere and Halloween upon us, the living dead are back in full-force.

Zombies are scary. We humans are evolutionarily pre-programmed to abhor the dead bodies of our own species. It's a natural reaction, helping healthy individuals avoid fatal pathogens.

The thought of being eaten alive is a natural fear, and when it's your own species doing the eating, it's even more terrifying.

Relax. Next time you're lying in bed, unable to fall asleep thanks to the vague anxiety of half-rotten corpses munching on you in the dark, remember this: if there was ever a zombie uprising, wildlife would kick its ass.

To enjoy zombie horror, you suspend disbelief and put aside some of science's rules. That said, if we assume zombies can't spread whatever is causing them to reanimate to other species, and that they are relatively slow moving—both true (so far! — Ed.) of Walking Dead zombies—there are more than enough wild animals out there to dispatch the undead.

That's because zombies are essentially walking carrion, and Mother Nature doesn't let anything go to waste.

Carrion is on the menu for a vast number of species, from tiny micro-organisms to the largest carnivores.

Here's just some of the North American wildlife that would make short work of a zombie horde.

Birds: Winged Zombie Annihilators

Many birds feed themselves by scavenging on dead things. The two vulture species native to North America, the turkey vulture and the black vulture, flock up to make short work of any corpses they find. Both vulture species are dwarfed by the massive California condor, whose wingspan can reach 10 feet and which relish carrion. A sluggish zombie wouldn't stand a change against one of these giants or a flock of vultures. California condors are endangered, so a zombie apocalypse could really give a boost to their population by providing them with an abundance of food.

This video shows a juvenile California condor ripping the heart out of a dead carcass, surrounding by ravens picking up scraps. Ravens are not small birds—just look at the size of this baby condor in comparison.

Ravens, crows, and magpies are expert scavengers as well, in addition to being bold and extremely intelligent. Many species of gulls, known for their brash behavior when it comes to scoring a meal, would also gladly feed off slow-moving zombies in coastal areas. These birds usually require other animals to break through or break down the tough skin and hide of their carrion meals. So they'd have to wait until the zombies decomposed a bit, or were dismembered by others animals, before they tucked in. But once started, nothing would stop them from devouring the undead with gusto.

Despite being expert hunters, eagles are not above scavenging. Bald eagles make carrion a regular part of their diet, and with their huge talons, they're not afraid to dispatch animals that are near-death—or undead. The slightly larger golden eagle is no stranger to scavenging, either, and has also been documented attacking and killing animals as large as deer. A torpid zombie wouldn't pose much of a challenge.

Watch these bald eagles and crows strip a deer carcass down to nothing in 48 hours.

Mammals: Zombie Dismemberment Crew

North America's large mammal predators would be more than a match for zombies. We have two bear species, brown (or grizzly) and black bears. Male brown bears can weigh in at 1,000 pounds. They are not afraid of humans. They can deliver a bite of 1200 pounds per square inch and have long, sharp claws designed to rip open logs and flip boulders in search of insects and other small critters to eat. They would easily tear apart rotting zombie flesh. Black bears are much smaller and typically run from humans, but even a black bear, when approached or cornered, would make short work of a zombie. Both bear species have an incredible sense of smell and both love to eat carrion, so even if zombies didn't approach them, the bears eventually would learn that these walking bags of flesh make good eating.

Like black bears, gray wolves are very shy of humans and typically run away at the first sight of us. Nor are they strangers to scavenging. They'd soon take advantage of the easy pickings presented by lumbering zombies. Coyotes are far less shy than wolves and can happily live alongside humans, including in the heart of our cities. These intelligent canids would quickly learn that they could take down zombies one by one, especially the eastern populations of coyote, which are larger and bolder due to past interbreeding with wolves and domestic dogs.

Unlike bears, wolves and coyotes, mountain lions prefer fresh meat and don't typically feed on carrion, other than what they kill themselves. Like all cats, they hunt by stealth and are irresistibly attracted to signs of weakness in potential prey. Unlike most other North American predators, mountain lions can put humans on the menu. Any zombie shuffling through mountain lion territory (which can be surprisingly close to our cities) would trigger those feline predatory instincts, and would likely end up with one of these big cats sneak-attacking from behind and delivering a spine severing bite to the back of the neck.

Even bigger and more powerful than mountain lions are jaguars, which range through Mexico and are still sometimes found in the desert southwest of the United States. Jaguars also hunt by stealth, and have a special technique to quickly dispatch their prey: a skull crushing bite to the head, delivered with their huge canine teeth. A jaguar bite delivers 2,000 pounds of pressure per inch, the most powerful mammalian bite on the continent. That, combined with a killing technique perfect for dispatching zombies, makes the jaguar its natural predator.

Watch this video of a jaguar making short work of a caiman. A zombie wouldn't stand a chance against these big cats.

It's not just mammalian carnivores that would take apart zombies. On The Walking Dead, Rick's horse fell victim to a horde of zombies in season one, but I can only chalk that up to the fact that it was a domestic beast that didn't view humans (even undead ones) as a threat. Wild hoofed mammals would not be so passive as to let zombies to get close enough to swarm and overwhelm them.

In fact, hoofed mammals are more dangerous to humans than carnivores. Moose attack and kill more people than bears do every year. They consider humans a threat, but as the largest living deer species, they are not afraid of human-sized creatures. If a zombie got too close, a moose would stomp it into an immobile pile of gore without a second's hesitation.

This video shows moose fighting technique, which involves delivering powerful blows with their sharp hooves.

And moose are nothing compared to bison. Bison are a ton of muscle, horn, and hide. They do not tolerate being approached, and would effortlessly gore and trample as many zombies as dared approached them. Watch this video of what a bison can do to a car with a flick of its head, and think about what a zombified human body would look like on the receiving end of its wrath.

Speaking of hoofed mammals ramming cars, this video of bull elk will give you some perspective on the size of this large deer species and their aggression during the breeding season. Bull elk are armed with giant antlers with spear-like tips—perfect to impale and dismember a pack of zombies.

Mountain goats would probably not encounter too many zombies, simply due to the inaccessibility of the steep mountain slopes they call home. Every so often, however, they do head down to more manageable terrain. Even though they are not large, they can be fierce and are armed with dagger-like horns, just as this unfortunate hiker learned.

Reptiles: Scaly Zombie Clean-Up Committee

Most North American reptiles—small lizards, turtles and snakes—wouldn't pose much threat to zombies. Ironically, it would probably be venomous rattlesnakes that would be at most risk from zombie attack. When camouflage fails them, their survival tactic is to draw attention to themselves with a loud rattle, and then hold their ground, striking out at anything that approaches them. With no circulatory system or living tissue, snake venom wouldn't have any effect on zombies, and they'd easily be able to pick up the snake and eat it.

That said, we do have a few reptiles particularly suited for zombie clean-up. Two crocodilian species call North America home: the American alligator and the American crocodile. American crocodiles are extremely endangered and found only in limited areas of Florida, but like California condors, they could benefit from an influx of slow-moving, half-rotten, staggering prey to their wetland habitat.

Alligators are far more numerous and are found throughout Florida, west to Texas, and along the coastal plain wetlands as far north as the Carolinas. Once almost totally wiped out, alligators are now numerous due to protections under the Endangered Species Act, and they sometimes even show up in people's backyards. 'Gators can grow to be 13 feet long and deliver an extremely powerful bite, with over 2,000 pounds of pressure per inch.

Both species are stealth hunters, and can burst from the water at surprising speeds to pluck large prey from the shoreline. They are quite capable of tearing a human-sized meal into bite sized chunks of meat with their toothy, vice-like mouths. Soft zombie flesh would melt in their mouths like butter.

Any zombie that lumbered into fresh water ponds, lakes streams or swamps would likely fall prey to aquatic turtles too, who, with their beak-like jaws, would feast on zombie flesh. Painted turtles, river cooters and sliders of all sorts make carrion a part of their normal diet. To the undead, it would be a second "death by a thousand bites." The ubiquitous common snapping turtle specializes in carrion-eating. As the name suggests, it can tear off substantial chunks and swallow them whole. Snapping turtles are even used by police to find corpses underwater due to their relish for dead flesh.

Common snapping turtles are dwarfed by the alligator snapping turtle, which is the world's largest freshwater turtle. They can weigh in at more than 200 pounds. Disguised to look like rotten leaves, resting in the murky depths which they live, they are the perfect foil for any zombie that ends up in the water. Check out the massive head on this one.

Decomposers: Masters of the Zombie Buffet

Ultimately, it's not the North America's mega-fauna that pose the most threat to zombies. In nature, there are a whole host of tiny creatures whose main purpose is to feed upon and break down the flesh of the dead: the decomposers. Zombies, with their rotting flesh, are obviously not immune to these decomposers (what do you think causes the rotting effect?), many of which are too small to see with the bare eye. Bacteria, fungi, molds, insects such as fly maggots or flesh-eating beetles, and other invertebrates, all make up nature's diminutive clean-up crew. And it can obliterate a dead body in surprisingly little time. The clumsy undead wouldn't have the dexterity to pick off these decomposers, even if they could see or feel them. It would just be a matter of time. Stripped off all soft tissue, including brains, the zombies would be reduced to hollowed-out skeletons.

Not convinced? Check out this video of a rabbit being consumed down to the bone, by wildlife decomposers, in just a week.

Here is a time-lapse video showing Dermestid flesh-eating beetles consuming the flesh off a series of birds for the Natural History Museum of London. These beetle are easy to raise in captivity and only feed on (un)dead flesh, so they pose no harm to the living. Survivors of a zombie apocalypse could raise these beetles by the millions, and drop them onto zombies to do their work. It might take a few weeks per zombie, but they'd get the job done.

Here are some maggots going to town on a carcass. Flies produce millions of grotesque larvae in no time at all. There would be no way for zombies to escape these flying insects—or avoid being engulfed utterly by writhing, insatiable maggots.

Zombies No Match for Wildlife, Wildlife No Match for Humans

There you have it. Even if zombies managed to feed on smaller, slow-moving animals, or mob and overtake a few individuals of the larger species, it's pretty clear that they're no match for much of North America's wildlife…at least not on a one-on-one basis. In reality, however, the battle between wildlife and living humans is not going so well for the wildlife.

Sadly, much of our continent's wildlife has disappeared, and many species continue to decline. Habitat loss, invasive species and climate change are just some of the human-induced challenges our wildlife are facing. You can get involved protecting wildlife with the National Wildlife Federation and help make sure that we have a future filled with these amazing species.