Camera trap damaged by elephants in Pakke Tiger Reserve

A camera trap is a

camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with ...

that is automatically triggered by a change in some activity in its vicinity, like presence of an animal or a human being. It is typically equipped with a motion sensor – usually a passive infrared (PIR) sensor or an active infrared (AIR) sensor using an

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...

light beam. Camera trapping is a method for capturing wild

animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage ...

s on film when researchers are not present, and has been used in ecological research for decades. In addition to applications in

hunting Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...

and

wildlife Wildlife refers to undomesticated animal species, but has come to include all organisms that grow or live wild in an area without being introduced by humans. Wildlife was also synonymous to game: those birds and mammals that were hunted ...

viewing, research applications include studies of nest

ecology Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...

, detection of rare species, estimation of population size and species richness, and research on habitat use and occupation of human-built structures. Camera traps, also known as

trail camera A remote camera, also known as a trail camera or game camera, is a camera placed by a photographer in areas where the photographer generally cannot be at the camera to snap the shutter. This includes areas with limited access, tight spaces where a ...

s, are used to capture images of wildlife with as little human interference as possible. Since the introduction of commercial infrared-triggered cameras in the early 1990s, their use has increased. With advancements in the quality of camera equipment, this method of field observation has become more popular among researchers. Hunting has played an important role in development of camera traps, since hunters use them to scout for game. These hunters have opened a commercial market for the devices, leading to many improvements over time.

Application

The great advantage of camera traps is that they can record very accurate data without disturbing the photographed animal. These data are superior to human observations because they can be reviewed by other researchers. They minimally disturb wildlife and can replace the use of more invasive survey and monitoring techniques such as live trap and release. They operate continually and silently, provide proof of species present in an area, can reveal what prints and scats belong to which species, provide evidence for management and policy decisions, and are a cost-effective monitoring tool. Infrared flash cameras have low disturbance and visibility. Besides

olfactory The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, ...

and acoustic cues, camera flash may scare animals so that they avoid or destroy camera traps. The major alternative light source is infrared, which is usually not detectable by

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...

s or

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s. Camera traps are also helpful in quantifying the number of different species in an area; this is a more effective method than attempting to count by hand every individual organism in a field. It can also be useful in identifying new or rare species that have yet to be well documented. By using camera traps, the well-being and survival rate of animals can be observed over time. Camera traps are helpful in determining behavioral and activity patterns of animals, such as which time of day they visit

mineral lick A mineral lick (also known as a salt lick) is a place where animals can go to lick essential mineral nutrients from a deposit of salts and other minerals. Mineral licks can be naturally occurring or artificial (such as blocks of salt that fa ...

s. Camera traps are also useful to record animal migrations.

Camera types

The earliest models used traditional film and a one-shot trigger function. These cameras contained film that needed to be collected and developed like any other standard camera. Today, more advanced cameras utilize

digital photography Digital photography uses cameras containing arrays of electronic photodetectors interfaced to an analog-to-digital converter (ADC) to produce images focused by a lens, as opposed to an exposure on photographic film. The digitized image ...

, sending photos directly to a

computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...

. Even though this method is uncommon it is highly useful and could be the future of this research method. Some cameras are even programmed to take multiple pictures after a triggering event. There are non-triggered cameras that either run continuously or take pictures at specific time intervals. The more common ones are the advanced cameras that are triggered only after sensing movement and/or a heat signature to increase the chances of capturing a useful image. Infrared beams can also be used to trigger the camera.

Video Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) sy ...

is also an emerging option in camera traps, allowing researchers to record running streams of video and to document animal behavior. The battery life of some of these cameras is another important factor in which cameras are used; large batteries offer a longer running time for the camera but can be cumbersome in set up or when lugging the equipment to the field site .

Extra features

Weather proof and waterproof housing for camera traps protect the equipment from damage and disguise the equipment from animals. Noise-reduction housing limits the possibility of disturbing and scaring away animals. Sound recording is another feature that can be added to the camera to record animal calls and times when specific animals are the most vocal. Wireless transmission allows images and videos to be sent using cellular networks, so users can view activity instantly without disturbing their targets. The use of invisible flash "No-Glow" IR leverages 940nm

waves to illuminate a night image without being detected by humans or wildlife. These waves are outside of the visible light spectrum so the subject doesn't know they are being watched.

Effects of weather and the environment

Humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity dep ...

has a highly negative effect on camera traps and can result in camera malfunction. This can be problematic since the malfunction is often not immediately discovered, so a large portion of research time can be lost. Often a researcher expecting the experiment to be complete will trek back to the site, only to discover far less data than expected – or even none at all. The best type of weather for it to work in is any place with low humidity and stable moderate temperatures. There is also the possibility, if it is a motion activated camera, that any movement within the sensitivity range of the camera’s sensor will trigger a picture, so the camera might end up with numerous pictures of anything the wind moves, such as plants. As far as problems with camera traps, it cannot be overlooked that sometimes the subjects themselves negatively affect the research. One of the most common things is that animals unknowingly topple a camera or splatter it with mud or water ruining the film or

lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements ...

. One other method of animal tampering involves the animals themselves taking the cameras for their own uses. There are examples of some animals actually taking the cameras and snapping pictures of themselves. Local people sometimes use the same game trails as wildlife, and hence are also photographed by camera traps placed along these trails. This can make camera traps a useful tool for anti-poaching or other

law enforcement Law enforcement is the activity of some members of government who act in an organized manner to enforce the law by discovering, deterring, rehabilitating, or punishing people who violate the rules and norms governing that society. The term ...

effort.

Placement techniques

One of the most important things to consider when setting up camera traps is choosing the location in order to get the best results. Camera traps near mineral licks or along game trails, where it is more likely that animals will visit frequently, are normally seen. Animals congregate around mineral licks to consume water and soil, which can be useful in reducing toxin levels or supplement mineral intake in their diet. These locations for camera traps also allow for variety of animals who show up at different times and use the licks in different ways allowing for the study of

animal behavior Ethology is the scientific study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objecti ...

. To study more specific behaviors of a particular species, it is helpful to identify the target species' runs, dens, beds, latrines, food caches, favored hunting and foraging grounds, etc. Knowledge of the target species' general habits, seasonal variations in behavior and habitat use, as well as its tracks, scat, feeding sign, and other spoor are extremely helpful in locating and identifying these sites, and this strategy has been described in great detail for many species. Bait may be used to attract desired species. However type, frequency and method of presentation require careful consideration. Another major factor in whether this is the best technique to use in the specific research is which type of species one is attempting to observe with the camera. Species such as small-bodied birds and insects may be too small to trigger the camera. Reptiles and amphibians will not be able to trip the infrared or heat differential-based sensors, however, methods have been developed to detect these species by utilizing a reflector based sensor system. However, for most medium and large-bodied terrestrial

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

camera traps have proven to be a successful tool for study.

References

External links

Softpedia: ''Camera trap photographs unknown animal''

An application of camera traps in ornithological research
{{Trapping Traps Biological techniques and tools Conservation biology Motion control photography Environmental Sampling Equipment