It refers to their long thin neck, which has a snake-like appearance when they swim with their bodies submerged, or when mated pairs twist it during their bonding displays.

They typically inhabit fresh water lakes, rivers, marshes, swamps, and are less often found along the seashore in brackish estuaries, bays, lagoons and mangrove.

Habitat destruction along with other human interferences (such as egg collection and pesticide overuse) are the main reasons for declining darter populations.

[2] Darters feed mainly on mid-sized fish;[5] far more rarely, they eat other aquatic vertebrates[6] and large invertebrates[7] of comparable size.

These birds are foot-propelled divers which quietly stalk and ambush their prey; then they use their sharply pointed bill to impale the food animal.

They do not dive deep but make use of their low buoyancy made possible by wettable plumage, small air sacs and denser bones.

[8] On the underside of the cervical vertebrae 5–7 is a keel, which allows for muscles to attach to form a hinge-like mechanism that can project the neck, head and bill forward like a throwing spear.

[9] Predators of darters are mainly large carnivorous birds, including passerines like the Australian raven (Corvus coronoides) and house crow (Corvus splendens), and birds of prey such as marsh harriers (Circus aeruginosus complex) or Pallas's fish eagle (Haliaeetus leucoryphus).

The long neck and pointed bill in combination with the "darting" mechanism make the birds dangerous even to larger carnivorous mammals, and they will actually move toward an intruder to attack rather than defending passively or fleeing.

Males display to attract females by raising (but not stretching) their wings to wave them in an alternating fashion, bowing and snapping the bill, or giving twigs to potential mates.

To strengthen the pair bond, partners rub their bills or wave, point upwards or bow their necks in unison.

To provide warmth to the eggs, the parents will cover them with their large webbed feet, because like their relatives they lack a brood patch.

[13][14] Anhinga is derived from the Tupi ajíŋa (also transcribed áyinga or ayingá), which in local mythology refers to a malevolent demonic forest spirit; it is often translated as "devil bird".

Some earlier authors included the darters in the Phalacrocoracidae as subfamily Anhingina, but this is nowadays generally considered overlumping.

[17] The Sulae are also united by their characteristic display behavior, which agrees with the phylogeny as laid out by anatomical and DNA sequence data.

While the darters' lack of many display behaviors is shared with gannets (and that of a few with cormorants), these are all symplesiomorphies that are absent in frigatebirds, tropicbirds and pelicans also.

The supposed traits uniting them, like all-webbed toes and a bare gular sac, are now known to be convergent, and pelicans are apparently closer relatives of storks than of the Sulae.

The Late Pleistocene Anhinga laticeps is not specifically distinct from the Australasian darter; it might have been a large paleosubspecies of the last ice age.

The other families placed in the Phalacrocoraciformes sequentially appear throughout the Eocene, the most distinct – frigatebirds – being known since almost 50 Ma (million years ago) and probably of Paleocene origin.

[23] Fossil Anhingidae are known since the Early Miocene; a number of prehistoric darters similar to those still alive have been described, as well as some more distinct genera now extinct.

With their considerable stamina and continent-wide distribution abilities (as evidenced by the anhinga and the Old World superspecies), the smaller lineage has survived for over 20 Ma.