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Mammal teeth: what a mouthful of teeth says about an animal’s diet
A mammal’s teeth tell you what it eats. Their function, size, shape and layout in the mouth are adapted to diet. This explainer follows a National Park Service article that uses horses at Assateague Island National Seashore as its example.
Image from the National Park Service’s page: a line drawing of the upper and lower jaw, showing the location of the tooth types.
Four kinds of teeth
| Tooth | What it does | Where it is |
|---|---|---|
| Incisors | Cut, bite, nibble and strip | Front of the mouth |
| Canines | Grab, pierce and tear | On either side of the incisors |
| Premolars | Grind, crush and slice | Along the jaw, next after the canines |
| Molars | Grind and crush, using the jaw's leverage for the most power | Along the jaw, with the premolars |
Mammals can be herbivores, omnivores, carnivores or insectivores. The number of each tooth type typically differs within a species and by the animal's sex and age. Most mammals have teeth, but anteaters, platypuses and some whales are exceptions.
Reading a diet from the teeth
Image from the National Park Service’s page: a carnivore skull.
- Carnivores eat mainly meat. Their canines and long teeth let them bite and tear, and even their grinding molars are sharp.
- Herbivores eat mainly plants. Their teeth cut and grind: tall molars with flat upper surfaces (sometimes ridged) and clipper-like incisors.
- Omnivores eat meat and plants. They have sharp, long canines and wide molars with low, bumpy crowns, so they can tear and cut as well as grind and chew.
Image from the National Park Service’s page: an herbivore skull.
Image from the National Park Service’s page: an omnivore skull.
Horses as a case study
Horses generally have between 36 and 44 teeth, shaped for different jobs. They are mainly herbivores and can graze for up to 15 to 17 hours a day. Their incisors, and the canines of male horses, cut plants, and their premolars and molars grind food before it is swallowed.
Eating plants wears the teeth. Grazing continually grinds them down, so over a horse's lifetime the teeth keep erupting from the jaw to stay at the same height, until none is left. If the animal lives to old age, the remains of a tooth fall out.
Because diet and tooth wear are directly related, scientists can learn much about a horse's diet and lifestyle from its teeth: the kinds of plants where it lived, its age, sex and overall health, and more. Archeologists, biologists and zoologists all study horse teeth.
Sources
- National Park Service, "Mammal Teeth," Assateague Island National Seashore (https://www.nps.gov/articles/000/mammal-teeth.htm); rewritten in hubnx's own words.