So, should we avoid going out at night or arm ourselves with the latest self-defense tools? Are we taking too many risks on our night hikes? Once you learn what is really making those scary sounds and why those eyes glow in different colors, you'll realize that you're more likely to trip and fall than be attacked by a wild creature. But if you're the type who prefers to have things remain mysterious and unknown, you can stop reading this article now and skip to the next one. However, if you'd like to feel more comfortable in the wilds after sundown, please read on.   

 The first question that many people may ask is why are animals active after dark anyway? Isn't it more difficult to find their food, avoid trail hazards or see other predators in time to flee? These problems would certainly prevent most animals from doing well in the darkness of nights without moonlight.  

However, many creatures have evolved special adaptations that allow them to “work the night shift” and avoid competing with other day-active animals for food and territories. Nocturnal animals, active only at night, are not as common as crepuscular critters who are most active around sunrise and sunset or diurnal wildlife which are active during the daylight hours. As you can imagine, the special adaptations these animals have developed allow them to see, hear and even smell better to compensate for the lack of natural light.

Enhanced vision is demonstrated by many species of owls, mammals, reptiles, amphibians and a few insects. Night-active animals usually have larger eyes, allowing more light waves through their lens like a pair of large expensive binoculars. They also have developed another adaptation that creates the scary eye glow when illuminated with a flashlight or spotlight. The eye glow is simply a reflection of the light off a special layer of mirror-like tissue, called the tapetum lucidum.  

These animals also have more rods, which are the highly light sensitive nerve endings, than diurnal wildlife. So, every photon particle of light entering the eye has a good chance of striking and stimulating a light sensitive nerve either in the first pass or after it has been reflected back from the tapetum lucidum. The reflective layer can be made of different materials which produce a different colored reflection including white, blue, green and yellow. Walleye shine white, deer and elk reflect light blue to light yellow, owls look red to yellowish, bears shine light green and the black-footed ferrets’ eyeshine is described as “Mountain Dew Green.” Eye shine color can vary depending on the type and angle of the light, amongst other factors.

Humans do not have this reflective layer, although the blood-rich retina sometimes glows red in photographs that happen to catch people looking into the flash with their iris wide open. We have more of the cone type nerve endings in our eyes which allow us to see way more colors than nocturnal animals. Human ingenuity allows us to minimally adapt to night conditions through expensive night vision equipment, in an attempt to mimic the amazing abilities of nocturnal wildlife. We just might have the advantage on animals in the infrared or heat-emitting viewing spectrum, using the latest technology, as this skill seems to be limited to snakes with pit organs like rattlesnakes, boas and pythons; some fish like goldfish and piranha as well as mosquitoes at close range.

Nocturnal wildlife also demonstrate adaptations in their sense of hearing, being over all more sensitive but also having evolved the ability to precisely locate the sound in a 3D space. Some critters do this with highly controlled movements of large ears which act like a satellite dish homing in on a weak signal from up to hundreds of miles away. Members of the dog and cat family use this skill every night. Owls have asymmetrically arranged ears on the sides of their heads (the feather tuffs on top are just for show) and the ability to tilt and twirl their entire head to infinite angles, triangulating on the sound many times per second. Those “curious” looks that animals show by cocking their heads in odd positions is actually an attempt to hear the sound from a different angle which helps nail down the most precise location of their subject. It's like taking multiple compass bearings on a landmark from different locations around it to see where most of the compass lines cross when plotted on a map. But the differences in bearings to the sound are much smaller when heard by an owl, further demonstrating Mother Nature's amazing ability to evolve incredible adaptations.

Wildlife calls made at night are not intended to be spooky but must be unique to allow easy identification and communication. Many critters call more at night since it is usually calmer and their calls carry further. Foxes and raccoons can produce some bone-chilling sounds that would be appropriate for use in any scary horror movie. Fortunately, there are many apps and websites that will play sound files of all owls and other nocturnal wildlife. Unfortunately, there is not an easy way to identify unknown sounds, other than listening to a lot of recordings. Expensive software is available to automatically help identify recordings of bird and bat calls but it can't identify everything and needs a clear and uncluttered recording.

Another incredible adaptation of some nocturnal wildlife and many deep-sea critters is echolocation. Even though there are no blind bats out there, they have greatly developed their hearing ability to compensate for low light conditions. This also includes their skills in producing the ultra-sonic calls above the frequency that humans can hear and focusing these sound waves like a spotlight to “illuminate” insects, obstacles and other bats. Coupled with their directional, and often times very large, ears they can track down a moving moth or mosquito in total darkness. And they pack all this technology into a body that weighs less than a penny in species such as the western pipistrelle which regularly reduces the mosquito and moth population in the White Mountains.

Some wildlife have evolved a very highly sensitive sense of smell to allow them to hunt in low light conditions. We learned that some snakes (it just has to be rattlesnakes, right?) can see in the dark with infra-red vision, focusing in on heat sources. Snakes can also use their tongues to catch particles of odor scent, sometimes at the molecular level, and judge from which direction they are coming. They have to transfer the odor particles to a special gland in the roof of their mouths, called the Jacobson's organ, for their brains to interpret the smells, even to the level of which fork in the end of their tongue had a higher concentration of the scent particles, allowing precise direction finding in the darkest conditions.  

Other animals active at night have also developed an acute sense of smell, like black bears. Biologists theorize that bears use their sense of smell to create a virtual map in their head using unique odors as their landmarks, coming from different directions around their home range, depending on the wind, instead of visual ones that we use like mountains and rivers and roads. Using this virtual map of smell landmarks is one way that bears may home back to their original territory in the dark even after being translocated dozens of miles into unfamiliar terrain.

So, it looks like nocturnal creatures have evolved a whole variety of ways to survive under low light conditions. Some folks might think that they use this against humans when we venture out at night, to scare and stress us out and maybe even eat us if they're hungry for a well-marbled roast. However, the facts tell a different story as we mentioned earlier. You are more likely to hurt yourself than be harmed by a nocturnal creature of the night. The proven deadliest creature of the night world-wide is the mosquito, so lather up with your preferred insect repellent and you can check that risk off the list. Don't worry so much about our native White Mountain wildlife if you make lots of noise and wear a headlamp on your ventures. Most wildlife is more afraid of you and will gladly flee your presence. Except maybe those ghosts and vampires- you might still want to watch out for them.