Birds
Anhinga
Anhinga anhinga · also called anhinga, snakebird, darter, water turkey, American darter
The anhinga is the “snakebird” of southern swamps — a long-necked, dagger-billed waterbird that swims almost completely submerged, with just its serpentine neck cutting the surface. It hunts fish by harpoon, and then, because its feathers soak up water on purpose, it has to sit on a branch with its wings spread wide until it dries out.
Overview
Anhingas live in warm, sheltered fresh and brackish water — swamps, marshes, slow rivers, lakes, mangroves — from the southeastern US to Argentina. They are usually seen doing one of two things: swimming low in the water with only the neck showing, or perched with wings fully spread to dry.
Wettable on purpose
A duck’s plumage is oiled and airtight to keep it floating high. The anhinga’s is only partly waterproof, so water soaks in, drives out the trapped air, and reduces buoyancy, letting the bird hang low and slip under the surface with no effort to stalk fish. The price is that afterward it is waterlogged and chilled and must spread its wings to the sun — often for an hour — before it can fly or hunt again.
The spear
Underwater, the anhinga holds its neck folded into a tight Z, locked by a hinge in the neck vertebrae. When a fish comes close, the neck straightens explosively and the sharp, slightly open bill is driven straight through the fish. The bird then surfaces, flips the fish off its bill, and swallows it head-first.
The other names
“Darter” for the harpoon strike; “water turkey” for the broad fan tail it shows while soaring high on thermals, often alongside vultures, between wetlands.
Status
The anhinga is Least Concern and stable, sensitive mainly to wetland drainage and disturbance at nesting colonies.
Anhinga: common questions
Why is the anhinga called a "snakebird"?
When an anhinga swims, it typically submerges its whole body and holds only its long, thin, S-curved neck and small pointed head above the surface, so from a distance it looks exactly like a snake gliding through the water. It can also sink slowly straight down, "periscoping" with just the head showing, and it swims underwater with the neck kinked ready to strike. The other names describe it too — "darter" for the harpoon-like dart of the neck when it spears a fish, and "water turkey" for the broad, fan-shaped tail it shows while soaring.
Why does the anhinga have to dry its wings?
Because its feathers are deliberately not fully waterproof, unlike those of ducks, gulls, or cormorants' close relatives. A duck's dense, oiled plumage traps air and keeps the bird floating high and dry; that would make it very hard to dive and stay under. The anhinga's plumage instead lets water penetrate, which floods out the trapped air, reduces the bird's buoyancy, and lets it hang low in the water and slip beneath the surface with almost no effort to stalk fish. The cost is that after a swim the anhinga is waterlogged, chilled, and too heavy to fly well, so it must climb onto a branch and hold its wings spread open to the sun and wind — sometimes for an hour or more — before it can hunt or fly again. This is why anhingas are almost always seen either swimming or perched in the "spread-eagle" pose.
How does it catch fish?
By spearing, not grabbing. The anhinga stalks slowly underwater with its neck folded into a tight Z, held in place by a specialised hinge in the neck vertebrae. When a fish is in range, the neck straightens in a fraction of a second and the sharp, slightly parted bill is driven straight through the fish's body like a two-pronged harpoon. The anhinga then surfaces, shakes or scrapes the fish off its bill against a branch or the water, tosses it into the air, and catches and swallows it head-first so the fins fold flat. It targets slow fish in warm, weedy shallows rather than fast open-water species.
How is an anhinga different from a cormorant?
They are related (both in the order Suliformes) and share the wing-drying habit and fish-eating lifestyle, and they overlap in the southeastern US, so they are often confused. Key differences — the anhinga has a long, straight, pointed, spear-like bill, while a cormorant's bill is shorter with a hooked tip; the anhinga has a much longer, thinner, more snake-like neck and a longer, broader, fan-shaped tail; the anhinga soars readily on thermals like a raptor, which cormorants rarely do; and the anhinga spears fish, whereas cormorants seize them in the hooked bill. The anhinga also favours calmer, weedier fresh water, while cormorants are more often on open lakes, rivers, and the coast.