What do bison eat?
Students collect and press grass, forbs, and browse. Students graph percentages.
- Students will be able to identify at least 3 major categories of food eaten by bison.
- Students will be able to identify three plants as a grass, forb, or browse.
- 3 X 5 Cards
- Cardboard Pieces
- Stack of books or other heavy objects
Bison are grazers. After dawn, in groups of three to four, the herd rises and eventually start grazing. They eat their fill and then rest. Their day cycles with periods of grazing and rest. It has been estimated that bison eat about 1.6 % of their body mass per day of dry vegetation. The equals 24 pounds a day. But what do the bison eat?
Bison eat grass as the greatest percentage of their daily diet. These animals eat approximately 93% grass, 5% forbs, and 2% browse as averaged over the course of one year.
Grass can be defined as the plants that are usually tufted or sod-forming herbaceous plants with narrow, elongated leaves. In the Panhandle area (where the State Bison Herd is located), bison eat grasses such as: Blue Stem, Buffalo Grass, and Gama Grass.
Forbs have broad leaves and considered a herbaceous plant. Many refer to forbs as weeds or wildflowers depending on their outlook. In the Panhandle Area, the bison may eat plants such as sunflower and coshia weeds.
Browse includes plants a with woody stem. Usually, you can peel a thin "bark" off browse plants. In the Panhandle Area, bison eat browse that includes mesquite and elm.
- Discuss with the students which plants are considered grasses, forbs, and browse. Explain to them that although bison may eat from these all three categories, bison eat mostly grass.
- Have students fill out the chart.
- Have the students collect examples of these plants. The plants collected by the students may be different than those eaten by the bison, but they still fall into the same categories. (If not possible for the students to collect the plants, the teacher should bring in examples of these plants.)
- Tag each of the plants with the name of the person who found the plant, the location where the plant was found, and the date.
- Create your own plant press using the following method. Note: Press only the leaves of browse material.
- Put the plant between the sheets of newspaper, using several sheets of paper between plants.
- Stack about 4 plants "newspaper sandwiches" together.
- Place a layer of cardboard on both the top and bottom of the plant/newspaper stack.
- Repeat the process of layering the plants in the newspaper and placing cardboard every fourth layer.
- Place heavy books or other heavy objects on the top of the stack to squeeze the water from the plants.
- Once the plants are dry, have the students place their collections in notebooks with clear pocket pages, in a photo album, or have them create their own "plant book."
- Present a forb, grass, and browse plant, and ask the students to classify each one.
- Ask students the three main categories from which bison eat.
- Have the students use field guides to determine the name of each plant.
- The teacher could bring in examples of forbs, browse, and grass. Then ask the students to classify each of the plants.
- Use rice, beans, and noodles as a manipulative to demonstrate the different percentages of plants consumed.
Grass- These plants are usually tufted or sod-forming herbaceous plants with narrow, elongated leaves.
Forbs- Any herbaceous plant growing in its native habitat except grasses and grass-like forms. Often considered weeds or wild flowers.
Browse- This group includes any plants with a woody stem. The bark can be peeled to reveal a woody center.
Herbaceous- Green colored plants with a soft stem, not woody plants.