id you ever find a bone while exploring In addition to teeth, other skull structures can the woods and wonder what animal it tell you whether an animal is a meat-or plant- belonged to? Bones, especially mammal eater. For example, there are numerous sites on skulls and jaws, can tell you a lot about the skull for muscle attachment, which vary the animal they came from. Whether it’s from species to species. In carnivores and just a partial jaw or a full skull, the bone’s omnivores, there is a ridge on top of the skull size, shape and structure provides you with called a sagittal crest. The site of muscle clues to the mammal’s identity and habits. attachment for the strong muscle that controls If you’re lucky enough to find an entire the crushing lower jaw, the sagittal crest is mammal skull, the first thing you should look quite pronounced on opossum and fisher, and at is its general size and shape. Is it large like less pronounced on coyote, raccoon and otter. a deer, or small like a rabbit? Is the skull Since herbivores typically have smaller jaw streamlined and narrow like an opossum, or muscles, they lack an obvious crest. broader and rounder like a raccoon? Are there Another interesting feature on a skull is the teeth, and if so, how many and what do they position and size of the eye sockets. Predators, look like? such as coyote and otter, generally have for- Teeth are great visual clues to an animal’s ward-facing eyes. This provides them with 3-D identity. They indicate what and how an animal vision, enabling them to more accurately locate eats. In many mammals, the teeth are quite and follow prey. In contrast, prey species, such distinctive. By examining the dentition (number as rabbits, have relatively large eyes located on and form of the teeth), you can tell whether the sides of their head. This gives them great the animal is a meat-eater (carnivore), plant- peripheral vision, aiding them in locating preda- eater (herbivore) or both (omnivore). Sharp, tors and warning them about sneak attacks. pointed teeth such as canines and carnassials While all mammal species have specific traits (last upper premolar and first lower molar and adaptations, keep in mind that animals can that meet with a scissorslike action) are used also be highly variable within a species, adjusting for tearing and shearing meat, indicating a to available conditions. For example, coyotes are carnivore. Broad, somewhat flat teeth are generally meat eaters, but will also eat fruit. used for crushing and grinding vegetation, Raccoons and opossums are considered omni- indicating an herbivore. Since omnivores, such vores, but they may be entirely carnivorous or as raccoons and humans, eat both plants and vegetarian depending on food availability. And meat, they have sharp teeth in the front to rip while deer are herbivores, they have been and cut, and flattened teeth in the back to observed to eat fish on occasion. mash their food. So next time you’re in the woods, or even in The condition of teeth (and bones) can pro- your own backyard, look around and see if you vide you with information about the animal’s can spot any mammal bones. While finding a history. For instance, heavily worn, damaged complete skull is rare, you’ll be amazed at what and cracked teeth may indicate that an animal you can find, and surprised at the amount of is old. Likewise, chipped, broken or missing information those bones reveal. teeth, or broken bones could mean the animal The following are a few mammals whose was in an accident or fight. bones you might find in New York’s outdoors.

NYS Department of Environmental Conservation Text by Eileen Stegemann Reprinted from the New York State Conservationist, April 2006 Artwork - Jean Gawalt / Layout & design - Frank Herec To subscribe, visit www.theconservationist.org or call 1-800-678-6399

sagittal crest

canines

carnassial COYOTE

Rabbit’s peripheral vision Skulls and teeth reveal a lot about an animal’s habits. This coyote has for- ward-facing eyes for binocular vision, canines for puncturing flesh, and a heavy carnassial pair for crushing dog-like animal, the coyote’s skull is bones. In contrast, a rabbit has eyes on Arather long with a large braincase and an the side of its head to see danger elongated snout. Like other predators, the approaching from almost any direction. eyes are located on the front of the head, giving the coyote binocular vision and better depth perception. Though largely a meat eater, a coyote's diet consists of a wide range of available foods, including deer, Rabbits snip rabbits, rodents, carrion, fruit, birds and twigs neatly insects. The coyote’s teeth are specially (left), while deer shred adapted for eating meat. It has large, round, the edges pointed canines for grabbing and stabbing (right). prey, and blade-like premolars and molars for both shearing and crushing bones. The skull has a low sagittal crest for muscle attachment to the crushing lower jaw.

Beaver’s incisors remove wood like a chisel. he continent’s largest rodent, the beaver losely related to rodents, the eastern ts "masked" face familiar to many, the Thas a thickly muscled body supported by Ccottontail rabbit is an herbivore, eating Iraccoon is a mischievous creature often large bones. Its skull and jaws are heavy to a variety of plants, including tender green known for getting into people’s garbage. support the four large bright-orange incisor vegetation, garden produce, bark and buds of An omnivore, it will eat vertebrates, teeth (two on top, two on bottom). Like all trees, vines and shrubs. Its jaw contains both invertebrates, fruits, nuts, berries, mice, rodents, the beaver’s chisel-like incisors are upper and lower front incisors which enable young birds, crayfish, frogs and turtle and deeply rooted in the skull and continue to it to neatly snip off plants. Unlike rodents, the bird eggs. It has a broad, rounded skull grow throughout the animal’s life. They use cottontail has two pairs of upper incisors— with a large brain case, and with eye these sharp teeth to fell trees for both food a small incisor lies behind each large, deeply- sockets that face forward like a predator’s. and building material. The incisors automat- grooved upper incisor. Popular prey for a The jaw contains canines and ripping teeth ically sharpen one another when the uppers number of predator species, the cottontail’s as well as grinding teeth, but like a bear, meet the lowers. Constant gnawing keeps skull has very large eyes sockets located on the raccoon has broad, low-crowned the teeth from growing too long. The its sides. This eye placement provides a wide molars shaped for crushing rather than beaver’s molar teeth function much like a field of vision, enabling the cottontail to more cutting. The raccoon’s scientific name, wood rasp, shredding and grating woody effectively spot predators. You can test this: lotor, refers to its habit of washing food plant fibers. Eye sockets and ear openings try to sneak up on a rabbit, even one that is before eating it. are located high on the beaver’s skull, facing away from you! In addition, the cotton- enabling this animal to see and hear while tail has very thin, light bones, which help the floating on the water’s surface. animal to run more quickly.

n herbivore, the white-tailed deer is large, mostly aquatic weasel, the river he opossum is North America’s only Aconsidered a browser or grazer, eating Aotter’s streamlined body is perfectly Tmarsupial. Recognized by its long, leaves, stems, buds of woody plants, fruits, shaped for moving quickly through water. bare, prehensile tail used during climbing, vines, mushrooms, grasses and acorns. Its skull is slightly flattened with an elongated it is a primitive animal with a very small The white-tail’s broad molar teeth are high- braincase, and its eye sockets are set high on braincase. Opportunistic, the opossum is crested and quite sharp for cutting, slicing the head, close to the nose. This eye place- an omnivore, eating whatever is available, and grinding. Like all mammals, the teeth ment enables this predator to accurately such as fruits, berries, insects, reptiles, wear down progressively as the deer grows view the surroundings while floating on the amphibians, smaller mammals, carrion older. Because a white-tail lacks upper inci- surface. The river otter eats fish and and garbage. Its skull can be distin- sors, it tears, shreds or roughly shears off crustaceans, amphibians (particularly frogs), guished from other mammals’ by the vegetation when eating, rather than neatly insects, birds and mammals. It has large, large number of teeth—a total of 50 in an snipping it like a rabbit. One distinguishing sharp canines for grasping prey, and its other adult, including 10 upper and 8 lower inci- feature of a deer’s elongated skull is the teeth are adapted for slicing and crushing. sors, large canine teeth, and a number of large gap on the lower jaw between the Otters range over wide territories, and their grinding teeth. The opossum’s skull contains front incisors and back teeth. A prey high metabolic rates make them voracious a number of strong muscle attachment species, the deer’s eyes are set somewhat eaters. sites, including a tall, well-defined, blade- to the side for better peripheral vision. like sagittal crest.