Dentition of herbivores

• why are plant cell walls tough to eat?

  as they contain cellulose and lignin, and, in some plants, silica
• why are the teeth of herbivores modified?

  they are modified so that, despite the plant cell walls being hard to eat, the cells are thoroughly ground up before entering the stomach
• what are examples of grazing herbivores?

  a cow or sheep
• where are the incisors located in grazing herbivores?

  they only have incisors on the lower jaw only
• how are the canine teeth of grazing herbivores indistinguishable from their incisors?

  they are indistinguishable from the incisors in shape and size
• how do grazing herbivores eat grass?

  the animal wraps its tongue around the grass and pulls it tight across the leathery ‘dental pad’ on its upper jaw then the lower incisors and canines slice through it
• what is the diastema?

  its a gap that separates the front teeth from the side teeth, or premolars
• what happens in the diastema?

  the tongue and cheeks operate in this gap, moving the freshly cut grass to the large grinding surfaces of the cheek teeth, or molars
• what happens after the freshly cut grass moves to the large grinding surfaces of the cheek teeth, or molars?

  • the molars interlock, like a W fitting into an M
  • the lower jaw moves from side to side and produces a circular grinding action in a horizontal plane
• what happens to the grinding surfaces on the teeth with time?

  they become worn, exposing sharp-edged enamel ridges, which further increase the efficiency of grinding
• why do the teeth of grazing herbivores continue to grow throughout the animals life?

  the teeth have open, unrestricted roots, so they continue to grow, replacing material worn down by chewing
• why does a herbivore not need strong muscles attached to its jaws?

  • as its food isn't likely to escape
  • its skull is relatively smooth, reflecting the absence of sites for strong muscles to attach
• what is this an image of?

  a skull of a sheep