Do Ducks Have Teeth? How a Duck’s Bill Really Works

No. Ducks have no teeth, and neither does any other living bird. If you have looked closely at a duck’s open bill and seen what appears to be a neat row of small teeth along the edge, what you were looking at is a set of ridges called lamellae — and they do a completely different job.

So what are “duck teeth”?

The rows of fine ridges you can see along the edge of an open bill. Ducks Unlimited’s waterfowl scientists describe them plainly: lamellae “act like sieves and look like teeth, even though ducks and geese don’t chew food.” How many there are depends on the species and its diet — the Cornell Lab notes that a northern shoveler’s bill carries “about 110 fine projections (called lamellae) along the edges that act like a colander, filtering out tiny crustaceans, seeds, and aquatic invertebrates from the water.” (Ducks Unlimited’s count for the shoveler is higher still — about 220 on the lower mandible and 180 on the upper — so treat any single number as a rough one.) A merganser’s are serrated for gripping fish, which is why it looks toothed. All of them are part of the bill’s keratin covering, not enamel set in bone. Nothing about them bites, cuts or chews.

What lamellae actually are

Lamellae are thin, comb-like plates running along the inner edges of both the upper and lower bill. They are made of the same tough material as the rest of the bill covering, they are not set in sockets, they do not have roots, and they are not used to bite or tear anything.

They are a filter.

When a mallard dabbles, it takes in a bill-full of water and mud, and then pumps it through with its tongue: a 2006 study by D. Brent Gurd describes ducks moving the tongue and both halves of the bill to push water one way, from the front of the bill to the back. The lamellae hold back food — seeds, insect larvae, tiny crustaceans — while the water is pushed out, and the ducks are not passive about it: the study’s title sums up its finding, that dabbling ducks “can actively select particles by size”. How much of the straining the lamellae themselves do is less settled: a 1989 study by Kooloos and colleagues found that shortening a mallard’s lamellae did not change how well it filtered, although it did for the northern shoveler, and proposed that small seeds are also separated out of the water flow by small eddies.

The species that look most convincingly toothed are the sawbills — mergansers and goosanders. Britannica describes their bill as having “toothlike edges and hooked tip for catching fish”, and the Wildfowl & Wetlands Trust describes “a hook at the tip of the bill and lamellae along the edges to help grip fish”. They catch fish rather than strain seeds, and a fish needs gripping. It is still not a tooth. It is a ridge shaped for a different job.

So how does a duck chew?

It does not. Chewing happens after swallowing, and it happens in the gizzard.

The gizzard is a thick, muscular chamber in the digestive tract, and it grinds. What it grinds against is grit: small stones the duck has swallowed on purpose and which stay in the gizzard doing the work teeth would otherwise do. The muscle contracts, the grit mills the food, and hard seeds that went down whole come out ground.

This is why grit matters for ducks you keep, though whether you need to provide it depends on the feed. Metzer Farms, a duck hatchery, puts it plainly: “If they are fed a mash, crumble or pellet, grit is not needed as the feed mill has ground the feed for them.” But “if they are fed whole corn, milo, wheat or other whole grains, grit is needed.”

The bill is also a sense organ

The tip of a duck’s bill contains a dense concentration of touch receptors — a structure sometimes called the bill tip organ. It gives the duck fine tactile discrimination at the very end of the bill, which means a duck feeding head-down in muddy water is not guessing. In a 2022 study, Pekin ducks foraging in muddy water separated mealworms from inedible pieces of clay, and learned to tell apart objects that differed only in hardness.

That is what makes dabbling work. The duck is not scooping blindly and hoping. It is reading the mud by touch, straining out what is worth keeping, and pushing the rest back out.

The one exception: the egg tooth

A duckling hatches with a small, hard, pale point on the tip of its upper bill. That is the egg tooth, and it is the only part of a duck that is called a tooth.

It is not a real tooth — Britannica describes the bird version as an “analogous horny structure” — but it does a real job. The duckling strikes the inside of the shell with it until cracks appear, and Ducks Unlimited says hatchlings finally emerge “after about 3 to 24 hours”. Once out, the duckling has no further use for it, and it falls off shortly after hatching.

If you want the rest of what happens in those first weeks, our guide to ducklings covers development from hatching to fledging, and raising ducklings week by week covers it from the keeper’s side.

Why birds lost their teeth at all

Some prehistoric birds did have true teeth. Modern birds do not. They keep what a 2006 study of a mutant chicken called “tooth developmental potential” — the mutant embryos formed crocodile-like first teeth — but a 2014 comparison of 48 bird genomes found that genes needed for dentin and enamel carry inactivating mutations shared by all of them.

Why they went is still argued over. The traditional explanation is weight; as the University of Bonn summarises it, “One assumes that a skull without teeth is lighter and thus better suited for flying.” But beaks also evolved repeatedly in dinosaurs that could not fly. A newer explanation is time: a 2018 study by Tzu-Ruei Yang and P. Martin Sander proposed, in the university’s words, that “The omission of time-consuming tooth formation could have been an effective way to shorten the dangerous incubation period.” Either way, a keratin bill can be shaped by evolution into an enormous variety of tools — a filter for a duck, a chisel for a woodpecker, hooks for a merganser catching fish.

Does this affect how you should feed a duck?

Less than you might expect. The standard advice is about nutrition rather than the bill. The Canal & River Trust suggests sweetcorn, lettuce, defrosted frozen peas, oats, seeds and rice, and says bread “is not particularly nutritional” — one of several reasons bread is a poor thing to bring to a pond. The wider picture is in what ducks eat.

So: no teeth, a filter for a mouth, a stone mill for a stomach, and a fingertip on the end of the bill. It is a stranger and better answer than yes.