Horrific, guttural cries, like an elderly woman screaming, have been heard in the middle of the night. Chickens and cats have been mysteriously killed. Is there something new to the woods of the Garden State, or has it always been there?

Since time immemorial, weird signs of elusive, unidentified creatures have persisted in New Jersey. For much of the past 200 years, they certainly would have been associated with the legendary Jersey Devil. This year marks the 100th anniversary of the most frantic burst of Jersey Devil sightings in recorded history, as reported by the Philadelphia Evening Bulletin in January 1909.

Rumored to inhabit remote regions of the Pine Barrens, the Jersey Devil is said to resemble a gruesome cross between a bat, a horse, and a kangaroo. Possibly the best description comes from Bruce Springsteen's epic song "A Night with the Jersey Devil": "Ram's head, forked tail, clove hoof, love's my trail." Local folklore traces the devil's origins to a woman known only as Mrs. Leeds, who cursed her unwanted 13th child on a fateful night in 1735 near Burlington.

One of the most plausible explanations of the legend is the hammer-headed fruit bat. With a wingspan of up to three feet, this mammal native to central Africa - scientific name Hypsignathus monstrosus - may have been unwittingly transported to New Jersey during colonial times or later, like many other invasive species. The bat has even been documented feasting on the blood of live chickens. With a description that diabolical, there is no need to invoke supernatural causes to resolve some devil sightings.

Lately, though, unusual reports have been attributed to the return of a carnivorous nocturnal mammal known as the fisher, a type of weasel with the ability to climb trees and even kill porcupines. By the late 19th century, unregulated hunting and deforestation eliminated fishers from New Jersey, along with wolves and cougars. But in recent years they have been verified as living in Sussex County, in the state's northwest.

As with the frenetic Jersey Devil sightings of 1909, a flurry of fisher sightings occurred in Hopewell Township in 2007. Numerous townspeople linked ungodly cries in the night to fishers, but the sounds were most likely cats or birds of some sort.

I investigated the matter by setting up remote motion-sensitive cameras and conducting track surveys in locations throughout the Sourland Mountains. I verified the presence of deer, raccoons, house cats, and coyotes, but not a single fisher - or Jersey Devil. However, the absence of evidence is not always evidence of absence.

So what, then, is the reality behind all of these strange sightings and sounds? Over the years, various explanations have been postulated, including: bobcats fighting, hoaxes unfolding, sandhill cranes mating, escaped cougars cavorting, mutant experimental animals rampaging, or mass hallucinations occurring.

But there may also be innate tendencies deep within the human psyche to believe we're encountering terrifying creatures, such as Bigfoot or the Loch Ness monster. These may be related to subconscious instincts that once guided primitive humans, before the formation of organized societies.

Fortunately, modern science and technology have helped us understand these demons of the wild. Remote camera traps, GPS units, and high-resolution digital cameras have enabled the general public to search effectively for rare wildlife. However, technology alone can never replace direct field experience, such as the wildlife tracking, observation, and habitat assessment essential to any naturalist's repertoire.

The possibility of discovering unknown or rare animals like fishers or cougars in our own back yards has an inherent intrigue, reinforcing our sense of wonder at the natural world and urging us to explore our environment. As a result, citizen-scientists are now ready to undertake the near-mythical quest to discover the phantoms in the forest. For example, citizen-scientist reports from areas of suitable habitat near the towns of Hampton, Montague, and Frelinghuysen have yielded critical insight into the status of fishers.

Future research efforts by the state Division of Fish and Wildlife, conservation organizations, and universities should enlist citizen-scientists to document endangered or hypothetical species. A new era has dawned in which the public, equipped with modern technology, can assist in improving statewide conservation measures. Whether searching for mythical creatures or elusive carnivores, citizens from Cape May to High Point can now join forces with professionals to unravel the mysteries of the deep Jersey wilderness, and in the process help protect what's left of it.

Charles Kontos is a Rutgers University wildlife biologist specializing in carnivore research and conservation. His field work helped lead to the rediscovery of fishers in New Jersey. He can be contacted at ckontos@eden.rutgers.edu.