The most prominent feature of the dab is its large eyes, which can be up to 2" in diameter on the common dab. Most species of dab have a pair of small horns, one located over each eye, and a short row of spines running down the back. These are believed to be vestigial defenses from a point in evolution when the dab had several natural predators. It is not known what these predators were, as no species of dab currently has any known natural predators.

This lack of natural predator may have contributed to a remarkable population growth in the last 50 years, and the dab is one of only a few noninvasive species to have such a population increase with little to no adverse effects on surrounding environments. The dab has very little impact on the local ecosystems it inhabits, subsisting mostly on small airborne particles which are caught and absorbed as the dab travels. The dab will also absorb small particles of plant matter, lichen, or dust mites by forcefully pushing itself against any hard surface. Most dabs in urban or suburban areas have also adapted to eating larger amounts of food scraps discarded by humans.

Biological classification of various species of the Dab family (Dabidae) is performed according to adult size, behavioral characteristics, and nominal altitude rather than by distinguishing features. Unlike most other amphibians, the coloration of each dab is determined by multiple factors in the environment at an early stage of development rather than genetics. In North and South America, the typical coloration is red or orange, while in Northern Europe, the coloration trends more toward black or green.

Although no fossil record of the species exists, Roman records found in modern-day France note the existence of a possible ancestor to the common dab as early as the first century BC. Historically, there was no scientific consensus on the classification of the Dab as an animal until the mid-1800s. The Dabidae family is currently classified as a sub-class of amphibians, but this has been contested by the biological community as recently as 2011.

In the wild, the dab shows very little awareness of its surroundings, often bumping against the same obstruction several times before moving around it. Furthermore, the lack of a mouth led many prominent scientists to suggest that the dab was instead a rootless plant or flower, and that its movement could be attributed entirely to wind currents and an aerodynamic, lightweight body structure.

Although not unique to the common dab, it is the only species of its size to create significant noise while moving. The common dab generates a soft humming sound which has been described as "similar to the operation of a small fan". The loudness of a typical dab during motion is 40-50dB, although measurements of up to 75dB have been observed.

The common dab is quite docile and does not appear to fear humans, even upon first contact. Many do not object to being touched or handled. Although professional breeders do not exist and no species of dab is considered a domesticated creature, there are approximately 10,000 dabs registered as pets in the United States. Dabs are considered an illegal exotic pet in 14 states.