A detection dog or sniffer dog is a dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

 that is trained to and works at using its sense

Sense

Senses are physiological capacities of organisms that provide inputs for perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...

s (almost always the sense of smell

Olfaction

Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...

) to detect substances such as explosives, illegal drugs, or blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

. Hunting dog

Hunting dog

A hunting dog refers to any dog who assists humans in hunting. There are several types of hunting dogs developed for various tasks. The major categories of hunting dogs include hounds, terriers, dachshunds, cur type dogs, and gun dogs...

s that search for game

Game (food)

Game is any animal hunted for food or not normally domesticated. Game animals are also hunted for sport.The type and range of animals hunted for food varies in different parts of the world. This will be influenced by climate, animal diversity, local taste and locally accepted view about what can or...

 and search dogs that search for missing humans are generally not considered detection dogs. There is some overlap, as in the case of human remains detection dogs

Police dog

A police dog, often referred to as a "K-9 dog" in some areas , is a dog that is trained specifically to assist police and other law-enforcement personnel in their work...

 (sometimes called cadaver

Cadaver

A cadaver is a dead human body.Cadaver may also refer to:* Cadaver tomb, tomb featuring an effigy in the form of a decomposing body* Cadaver , a video game* cadaver A command-line WebDAV client for Unix....

 dogs), trained to detect human remains.