skulls – Discover-Nature

Beaks or bills? Two interchangeable words naming the horny part of the jaw of a bird. They have numerous uses including gathering food, feeding, preening, and display, and are often used for functions that would be accomplished by arms and hands on other animal species. Let’s take a closer look at their structure and how birds use them for feeding.

Beaks come in a variety of sizes, and most are proportionate to the size of the bird’s head. Two or more of the bones comprising the lower jaw in birds are often fused together, increasing the strength of the overall structure. Birds do not have teeth, allowing the jaw bones to be lightweight, making it easier for a bird to hold its head out in front of its body while flying.

^{Barn owl, Tyto alba, skull showing fused jaw bones by Didier Descouens, Jul 2010}

Beaks are made from bone covered with keratin, a structural protein providing strength and rigidity. Yet beaks have some flexibility which adds to their dexterity when in use. The inner surface of the keratin layer is constantly growing while the outer surface is equally being worn away by use. Both upper and lower jaws are jointed where they attach to the skull, allowing for extended movements including the ability of a bird to open its jaws wider than most other animal species.

^{Great white pelican, Pelecanus onocrotalus, by Craig Adam, Feb 2013; Red-headed woodpecker, Melanerpes erythrocephalus, by Mark Moschell, May 2016; Evening grosbeak, Hesperiphona vespertina, by Fishhawk, Feb 2021}

A beak is specialized for every species depending on diet and food gathering methods. Cone-shaped beaks, found among cardinals, grosbeaks, and finches, can trap, cut, and crush seeds. Scoop-shaped beaks allow skimmers, spoonbills, and pelicans to slide their lower jaw under slippery prey, then catch and hold onto it . Beaks tipped with a chisel-like point are used by woodpeckers probing into crevices in hard materials. Along with a reinforced skull, keratin reinforces the beak’s toughness, standing up to repeated hammering and prying movements.

^{From upper left: Blue-gray gnatcatcher, Polioptila caerulea, by Dave Wendelken, Jul 2023; Pied flycatcher, Ficedula hypoleuca, by Edward Anderton, Jun 2012; Ruby-throated hummingbird, Archilocus colubris, by Mark Moschell, Jun 2019; Great-horned owl, Bubo virgianus, by Kevin Milazzo, Feb 2021}

Narrow tweezer-like beaks, used by gnatcatchers, warblers, and wrens, stab or seize small insects from branches. Wider and flatter tweezer-shaped beaks on purple martins and flycatchers can snatch an insect in flight. Long, slender beaks on hummingbirds are made for sucking nectar from the deep recesses of long, tubular flowers as well as catching tiny insects, such as fruit flies. Sharply pointed, hooked beaks are used by eagles, owls, hawks and shrikes to stab prey and hold on while pulling the meat apart into mouthful-sized chunks.

Many beaks serve more than one feeding function, as species change their diet from one type of food to another as seasons change. Tongues are an important addition to the mouth, manipulating food items for beaks to be more effective. Different sizes and colors of beaks convey information to other individuals about a birds sex and maturity level. This essential body part provides birds with many of the same capabilities as other animal species. Come to the Jurica-Suchy Nature Museum, or a nature center near you, to learn more about the many adaptations of birds.

^{Ruddy Duck, Oxyura jamaicensis, by Sergey Yeliseev, Nov 2013}

^{Grizzly Bear Ursus arctos, by Don Arnold, JSNM 2025}

As in many other natural history museums, the Jurica-Suchy Nature Museum displays mounts of animals or their parts including bones, skulls, teeth, pelts, claws, and feathers. Osteology is the study of bones in order to understand their structure and function, and how they relate to an animal’s lifestyle. At our museum we have several species of bears on display, plus bear skulls, bones, and claws for additional study.

^{Black Bear Ursus americanus, skull and dentition by Don Arnold, JSNM 2025}

Looking at a bear’s skull, we can see that they have up to twelve front teeth used for nipping and cutting. Their four long, sharp canine teeth are used to grab and hold their prey, and to tear apart the meat. There is a space between the front teeth and the flat molars in the back of the mouth, often found on herbivores, animals that eat vegetation. Bears are omnivores, including both meat/protein and vegetation in their diet, eating any small mammal up to the size of a deer fawn in addition to plants, seeds, and berries of all kinds.

^{Kodiak Bear Ursus arctos middendorffi, long & large nose by Don Arnold, JSNM 2025}

^{Polar Bear Ursus maritimus, skull and nasal opening by Don Arnold, JSNM 2025}

The long and large nose is another prominent part of a bear’s skull. A large nasal opening contains a complex system of bony plates intricately woven together. The plates create a much larger surface area than only the inside walls of the nasal opening, and are all covered with membranes capable of detecting scent. Bears have an excellent sense of smell, about seven times better than a bloodhound and more than 2,000 times better than a human. They can distinguish one or more scents from among dozens, detectable from as far away as two miles. Bears use their sense of smell to find food, mates, and family, and to identify potential threats.

^{Grizzly Bear Ursus arctos, small eyes & ears by Don Arnold, JSNM 2025}

^{Polar Bear Ursus maritimus, nose, ears, eyes by Don Arnold, JSNM 2025}

The ocular (eye) openings indicate that a bear’s eyes are located on either side of its nose, and face forward. This provides bears with binocular vision allowing them to see three-dimensional images and judge depth-of-field, the distance between a near object and a farther away object. Knowing how far away and how big another animal is compared to itself enhances its abilities to find and capture prey as well as avoid potential predators. Ear openings, at the lower back of the skull are difficult to find. The openings are tiny, and the auditory bone inside is small and flat. Bears have small eyes, with average eyesight, and small ears with slightly less than average hearing capabilities.

^{Polar Bear Ursus maritimus, sharp}
^{claws by Don Arnold, JSNM 2025}

^{Grizzly Bear Ursus arctos, claws for digging by Don Arnold, JSNM 2025}

^{Black Bear Ursus americanus, grasping claws by Don Arnold, JSNM 2025}

Their claws, another important part of a bear’s body, serve many functions to help them to survive in their environment. A polar bear’s claws are about five inches in length, thick, sharp, and slightly curved. They are used to gain traction on the ice when running or pulling themselves out of the water and onto an ice floe. A grizzly bear’s claws are about the same size, but stouter and not as sharp. They are used for pulling logs apart, digging dens, and scratching roots and invertebrates out of the ground. Black bears have the shortest and straightest claws, about two inches in length. They are sturdy claws, not as good for hunting and digging, but are excellent for climbing trees, an activity used by smaller bears that can pull their own weight upwards.

^{Black Bear Ursus americanus, tree climbing by Don Arnold, JSNM 2025}

Many other facts can be learned about the lifestyles of bears from around the world by studying bones, skulls, skeletons, paws, and whole specimens. Consider visiting us at the Jurica-Suchy Nature Museum to learn more by making a reservation at: JSNM Reservations (http) (enter hotlink)

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Bird Beaks

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