Dog collar

A dog collar is a piece of material put around the neck of a dog. A collar may be used for restraint, identification, fashion, protection, or training. Identification tags and medical information are often placed on dog collars. Collars are often used in conjunction with a leash for restraining a dog. Collars can be traumatic to the trachea if the dog pulls against the restraint of the leash, causing severe pressure to the neck. Use of a harness instead of a collar may be beneficial for dogs prone to tracheitis or those with a collapsed trachea. Conversely, dog breeds with slender necks or smaller heads may easily slip out of collars that are too loose. This can be avoided by using a martingale dog collar which tightens to distribute pressure around the neck when training the dog not to pull. Any style of dog collar must be properly fitted to ensure safety and collars should not be worn when the dog is unattended.

Basic collars

Collars are made with a variety of materials, most commonly leather or nylon webbing. Less common materials can include polyester, hemp, metal, or "oilcloth". Collars can be decorated in a variety of ways with a variety of materials. The basic collars for everyday wear are:

Buckle collars, also called flat collars, with a buckle similar to a belt buckle, or a quick-release buckle, either of which holds the collar loosely around the dog's neck. Identification is commonly attached to such a collar; it also comes with a loop to which a leash can be fastened. This is the most standard collar for dogs. A flat collar should fit comfortably tight on the dog's neck. It should not be so tight as to choke the dog nor so loose that they can slip out of it. Generally, two fingers should be able to fit underneath the collar.
Break-away collars look similar to buckle collars, but have a safety mechanism installed that allows the dog to break free of the collar if excessive force is applied. These collars are useful in situations where a non-quick release collar could get snagged and strangle the dog.
Safety stretch collars contain an elastic panel in the sturdy nylon collar, which allows escape from potential strangulation dangers such as branches, fences, gates and other dogs. Unlike breakaways, a stretch collar acts like a traditional collar when clipped with a leash.
Special-purpose collars and attachments
Stud collars, also called wolf collars, protection collars, or spiked collars depending on the attachments, are collars fitted with metal studs, dulled points, or sharp points that traditionally prevented another animal from biting the dog's neck. Commonly, spikes are hand-set and tightly riveted for extra security. This type of collar dates back to ancient Greece, when dogs protecting livestock were given nail-studded collars to protect them from wolves or other predators. In modern societies, stud collars are more commonly considered a fashion accessory.
Reflective collars, usually made with nylon webbing, incorporate reflective tape that ensures that the dog will be seen at night by approaching vehicles.
A lighted collar is a collar that emits light in order to make a dog more visible in the dark to their owners and more importantly, nearby motorists. It is not designed to help a dog see at night, as it is well documented that dogs have very good vision in low light conditions. Most lighted collars utilize one or more light emitting diodes for the light source and can be of virtually any color, although red and blue are most common. Power is provided by one or more batteries, most common types being AAA and lithium coin cells to minimize the added weight to the collar.
A flotation collar is a buoyancy aid designed for dogs. Although it is not designed to be used as a life preserver or life jacket, it can provide additional buoyant support for the head of a dog when in the water. It is often used in canine hydrotherapy services to assist in the rehabilitation of injured dogs. The collar may be constructed of closed cell foam material that is inherently buoyant or be of a type that is inflated with air.
Medical collars
Flea collars are impregnated with chemicals that repel fleas. They are usually a supplementary collar, worn in addition to the conventional buckle collar.
Elizabethan collars, shaped like a truncated cone, can be fitted on a dog to prevent it from scratching a wound on its head or neck or licking a wound or infection on its body.
Fashion collars

Dog collars are also used to convey the owner's style and have been used as a status symbol. The oldest known fashionable dog collars come from ancient Egypt, dating back to before the earliest of the Pharaohs. Today's fashionable dog collars come in a wide variety of designs, patterns and materials and may include accessories, such as bow ties and flowers.

Training collars

Several types of collars are used for the purposes of training dogs, though sometimes a collar is not used at all. Each training collar has its own set of advantages and disadvantages which trainers might consider before using a select one. Training collars are typically used for training only and not left on the dog's neck all the time, as some collars can be harmful or dangerous if left on a dog unsupervised.

Flat collars

Some dogs are trained on leash using a buckle or quick-release collar.

Martingale collar

are recommended for sighthounds because their heads are smaller than their necks and they can often slip out of standard collars. They can, however, be used for any breed of dog. Their no-slip feature has made them a safety standard at many kennels and animal shelters. A martingale collar has 2 loops; the smaller loop is the "control loop" that tightens the larger loop when pulled to prevent dogs from slipping out of the collar. A correctly adjusted martingale does not constrict the dog's neck when pulled taut. Others use them fitted snugly to be able to use them in a similar manner to a choke chain but without the unlimited constriction of a choke chain. The structure allows the collar to be loose and comfortable, but tightens if the dog attempts to back out of it.

Head halters

Head halters, also called head collars, are similar in design to a halter for a horse. They are sold under several brand names. Brands include Comfort Trainer, Canny Collar, Halti, Gentle Leader, and Snoot Loop amongst several others. Brand names are also used when referring to these collars most commonly Halti or Gentle Leader. This device fastens around the back of the neck and over the top of the muzzle, giving more control over a dog's direction and the intensity of pulling on a leash than most collars that fit strictly around the neck. Pressure on this type of collar pulls the dog's nose and consequently their head towards the handler. These types of collars can aid in stopping a strong dog from pulling an owner in an unsafe direction. They are also recommended for dogs that pull as the pressure will no longer be directly on their wind pipe.
The theory behind the utility of head halters is that if you have control of the head, you have control of the body. The head collar generally consists of two loops, one behind the ears and the other over the nose. This tool generally makes it more difficult for the dog to pull on its leash. This is a management tool only, it does not train the dog not to pull.

Controversy

Supporters of the head halter say that it enables the handler to control the dog's head, and makes the dog unable to pull using its full strength. They claim it is especially useful with reactive dogs, where control of the dog's head can be a safety issue.
Those who do not recommend use of the head halter say that some dogs find it unnatural and uncomfortable. If the collar is too tight, it may dig too deeply into the skin or the strap around the muzzle may push into the dog's eyes. Cervical injury is a possible result from improper use of the head halter; if a dog is jerked suddenly by the leash attached to the head halter, the dog's nose is pulled sharply to the side, which might result in neck injury. If the nose strap is fitted too tightly, the hair on the muzzle can also be rubbed off, or the dog might paw and scratch at its face, causing injuries ranging from mere bare skin to severe abrasions.
Some head halters such as the Canny Collar attach behind the neck and tighten around the nose when the dog pulls to deter the dog from pulling. Manufacturers claim they are safer than halters that attach below the muzzle because they do not pull the dog's head to one side, avoiding stress on the neck area. Some rear-fastening head halters can have the noseband removed during use, therefore providing an element of training the dog to eventually walk on a regular collar and lead.

Aversive collars

Aversive collars use levels of pain to encourage a dog to modify unwanted behaviors. The use of aversive collars is controversial, and the Association of Professional Dog Trainers and the American Veterinary Society for Animal Behavior prohibits their use. Many European countries have made shock collars illegal. Some countries have made prong collars illegal, and some have made choke collars illegal.
A meta-review of 17 peer-reviewed studies found that "The results show that using aversive training methods can jeopardize both the physical and mental health of dogs."

Shock collars

Shock collars consist of a radio receiver attached to a collar with battery and electrodes and a transmitter that the trainer holds. When triggered, the collar delivers the aversive of electrical stimulation to cause pain to the neck of a dog.
Shock collars are illegal in Spain, Germany, Austria, and Denmark, Netherlands, Iceland, Norway, Sweden Slovenia and Switzerland, Portugal, Wales, the province of Quebec in Canada, some states in Australia, and England.
Shock collars will be banned in Flanders in Belgium after 2027.
Some shock collar models also include a tone or vibrational setting, as an alternative to or in conjunction with the shock. Early shock collars provided only a single, high-level shock. "Although collar-produced shock can cause acute pain, the painful event does not and cannot produce physical injury". However, meta-studies have shown that they produce stress, cause pain, and damage the relationship between dog and owner. A leash or lead is not attached to a shock collar because it can pull the contacts too close to the dog's skin, causing lessened effectiveness of the collar and additional discomfort.