Envirothon- Mammal Skulls

Page 3: Identifying Mammal Skulls

  • Distinguishing features called Best Recognition Factors (BRF) help identify animal skulls

  • BRFs can determine the class (herbivore, carnivore, omnivore) and species of the skull

Page 5: Mammal Teeth

  • 4 main types of mammal teeth: incisors, canines, premolars, molars

  • Incisors: located at the front, used for cutting and shearing food

  • Canines: long and curved, used for piercing and tearing food

  • Premolars: flat biting surface, may have cusps, used for tearing and crushing food

  • Molars: flat biting surface, may have cusps, used for chewing, crushing, and grinding food

Page 6: Mammal Teeth (continued)

  • Carnivores (meat eaters): teeth designed for cutting, tearing, and piercing; small incisors; large sharp canines; premolars/molars used for shearing.

  • Herbivores (plant eaters): teeth designed for breaking down tough plant foods; wide incisors for stripping vegetative matter; small or absent canines; grazers premolars/molars very flat; browsing animals premolars/molars low, sharp cusps

  • Omnivores (meat and plant eaters): combination of herbivore and carnivore teeth; long sharp canines, not too long; premolars have sharp cusps; molars are squared off and bumpy.

Page 7: Carnivores

  • Carnivores have long canines for ripping and tearing meat

  • Sharp molars at the back of the mouth for further ripping and shredding

  • Binocular vision with eyes at the front of the head for depth perception

  • Examples of carnivores: otters and bobcats

Page 8: Herbivores

  • Herbivores have well-developed flat premolars and molars with sharp ridges

  • No canine teeth, large incisors for snipping off foliage

  • Eyes on the side of the head for a wider field of view

  • Examples of herbivores: rabbits, beaver, nutria, muskrat, white-tailed deer

Page 9: Omnivores

  • Omnivores have a variety of teeth

  • Eyes on the front of the head like carnivores

  • Examples of omnivores: black bear, raccoons, coyote, fox, opossums

Page 10: Mammal Nose and Eye Features Can Also Help To Identify Skull Species

  • The Rostrum: nasal area

    • Size is related to importance of smell

    • Herbivores have long noses

    • Noses vary for omnivores and carnivores

  • Eyes in the front, the animal hunts. Eyes on the side, the animal hides.

  • Orbit: part of skull around the eyeball

    • Carnivores have large forward facing orbits allowing for binocular vision and depth perception

    • Herbivores have eyes on the side allowing sight in all directions (almost 180 degrees of vision per side)

    • Grazers tend to have eyes high on the head to see above grass (ex. Cows)

    • Browsers have eyes far back on the skull to avoid twigs and preserve vision when their noses are in brush (ex. Deer)

    • Omnivores tend to have orbits facing partially forward maintaining a wide field of view and decent depth perception

    • Water animals have high orbits for above-water eyes

    • Nocturnal animals have large eyes and orbits for night vision