Category: Biology (Page 36 of 40)

Goats and Sheep, and… Science?

Someone asked me the other day for ideas for a science fair project using goats and/or sheep. Can you mix science and domesticated animals? Here’s a few ideas.

Public Domain Photograph by Jean Beaufort at Publicdomainpictures.net

Goats and sheep are amazing creatures. They were among the earliest animals domesticated by humans, second only to the dog. They occur throughout the world, along with their wild cousins like the mountain goats and bighorn sheep.

How are goats and sheep similar? How are they different? Do some research and create a Venn diagram.

1. Goat and Sheep Basics

Although they look somewhat similar, sheep and goats belong to different genera. The scientific name for sheep is Ovis aries. The scientific name for domestic goats is Capra hircus.

Female goats are called does or nannies.
Male goats are called bucks.
Baby goats are called kids.

Female sheep are called ewes.
Male sheep are called rams.
Baby sheep are called lambs.

Products we may get from goats:

  • Milk – used to make cheese, candy, milk, soap
  • Meat
  • Leather
  • Cashmere
  • Mohair
    Can also be used as pack animals.

Products we may get from sheep:

  • Milk – Yes, there are sheep dairies! – used to make cheese
  • Meat
  • Wool
  • Lanolin

If you are interested in food science, then find some goat and/or sheep milk and make some cheese.  You might compare the products from the two types of milk, or modify the process, for example comparing goat cheese made with lemon juice versus goat cheese made with vinegar.

2. What do goats and sheep eat?

Goats can eat many plants: shrubs, bushes, trees, aromatic herbs, even paper. But they don’t really eat tin cans. Goats eat many weeds and are used for weed control around the world. They even take care of poison ivy and poison oak. Study their diet in your area, and see if there are any differences in different habitats.

Sheep prefer to eat grasses.

Do sheep graze the same as goats? How are the two different?* (Answer at bottom)

3. Compare sheep and goat anatomy:

Sheep and Goats both belong to the Family Bovidae, which are hooved mammals with permanent horns. Horns are bony outgrowths that are covered with a sheath of material that is similar to a human’s fingernails. Horns are permanent, unlike antlers they are not shed. Most goats have horns, but they are usually dehorned while they are young. Most domesticated sheep breeds lack horns, although some rams still have horns. The wild versions of goats and sheep do have horns. The male bighorn sheep are known for their huge horns.

The hooves of goats and sheep grow over time, like our fingernails and so must be trimmed regularly. Although you might think hooves would be slippery to walk on, goats and sheep are remarkably agile. Goats can climb very well. Bighorn sheep can travel up steep mountains with ease.

4. Behavior

There are big differences between how sheep and goats behave. For example although both are herd animals, sheep tend to stick together whereas goats are more independent and curious.

Goats and sheep can also vary in behavior from breed to breed. You’ve probably heard of the specialized breed called fainting goats, which are goats that fall over when they are frightened.

If you have goats or sheep to study, you might want to examine differences in their response to novel stimuli, flocking behavior (like is one of the goats or sheep a leader?) or ability to learn, etc.

5. The Future?

For more futuristic science, check out this video of goats that have been modified to produce spider silk in their milk.

6. Read a Great Children’s Book

For a unit on goats and sheep for the youngest set, try these cute children’s books (covers are affiliate links to Amazon):

Charlie Needs a Cloak, by Tomie dePaola. Published by Simon & Schuster, 1973. From sheep, to yarn to cloak, this easy book follows the process of making cloth from wool.


Farmer Brown Shears His Sheep, by Teri Sloat. Published by Scholastic, 2000. A fast-paced, rhyming version of how wool becomes yarn. “ A yarn about wool.”

The Goat in the Rug as told to Charles Blood and Martin Link. Published by Four Winds Press, 1976. Story of a Navajo woman using goat wool to weave a rug.

*Sheep graze to the ground. Goats are browsers, which means they nibble on plants of all heights (as far up as they can reach).

Bird Migrations

Did you know that most songbirds, and many other birds migrate at night? When we went outside on Tuesday night to check the stars and look for meteors, we saw something amazing. We saw a flock of birds flying, eerily silent. At the risk of sounding anthropomorphic, they seemed incredibly focused on their destination as they disappeared into the blackness. It was not what we expected to see.

Science Friday, the radio program, recently had a broadcast about night migrations by birds, and how scientists study bird migration in general. On the Science Friday Tracking Bird Migration page, you can listen to a podcast of the show and find links to the speakers, as well as to other Internet resources on bird migration.

The broadcast raises a number of interesting questions, such as why do birds migrate? The consensus seems to be food. Most of the species that migrate depend on food that just isn’t available during cold winters. The speakers also noted that, unlike the birds we observed, many songbirds do call while they are flying and one way to study the migrations is to record the sounds they make.

Why do birds, normally active during the day, fly on their migrations at night? Several factors may be involved, and different species may fly at night for different reasons. It is thought that the air is calmer at night because the heat of the sun creates turbulence during the day. It also may be possible that fewer flying predators are active at night. Scientists have shown that birds use fixed stars to guide them on their flight, so perhaps they can orient better at night. Finally, it is cooler at night and flight is hard exercise, so perhaps it is easier to fly at night.

Bird Migration Activities:

1. Birdwatching

By watching birds in your area and keeping records of what you see, you can learn a lot about which birds migrate and at what times of year. Younger children can learn to identify common bird species and keep a simple nature journal.

Children might like to go on a bird walk at a park, nature center or garden. We recently watched this flock of lesser goldfinches at the Desert Botanical Garden in Phoenix. Birds often feed in flocks to store up energy for long flights.

In addition to keeping your own records, you can participate in national and international bird counts:
Audubon’s 110th Christmas Bird Count, December 14, 2009 to January 5, 2010

The Great Backyard Bird Count February 12-15, 2010

2. Watch Radar

It is possible to monitor bird migrations using radar. Here’s an example of a radar map used to track bird migrations. Radar maps are often available on weather websites. What a great way to reinforce map skills and learn about science, too.

3. Learn about Bird Banding

Scientists place tiny aluminum bands around the legs of birds to help find out where they go. As you will see in this video, you need to be trained by a professional before you should attempt this. It is good to know about it, however, in case you ever find a bird that has been banded.

4. Garden for Birds

Plant native plants in your neighborhood that provide fruits and seeds for birds to fuel their migrations. Check with local birding groups for suggestions.

Be sure to let us know what you find out.

Tree Leaf Science Activities

Did you do the tree leaf age experiment last spring to see how long tree leaves stay on the tree? Now would be a good time to check your trees. Let us know what you found out so far. Some of the leaves we marked on our orange tree last spring are still on the tree.

If you live where trees are deciduous, you might want to study the next step:  what happens to leaves when they fall off the tree?

First, think about and make a list of what you think might happen. Do you think some might be eaten, or that they will all blow away?

 

Scientists study the decomposition, or breakdown of leaves, by putting leaves in nylon mesh bags and letting them sit on the ground for long periods of time. The researchers come back every few weeks and pick up a few bags to take back to the laboratory. They open the leaf bags up and see what is happening. They look at things like how much weight the leaves lost, what kinds of critters have been eating the leaves, and how the leaves have lost chemicals (nutrients) over time.

You can make your own leaf bags (also called litter bags).

Gather:

  • Heavy duty screen door nylon mesh (1 x 2 mm mesh size is best) or the nylon mesh bags that fruits or onions come in from the grocery store.
  • Equipment, such as scissors, for cutting screen mesh
  • Equipment for closing the screen bag: glue gun or sewing needle and thread (soldiering irons can be used by adults).
  • Place you can safely leave leaf bags under trees and be able to retrieve them over time

If you are using the pre-made nylon bags from the grocery store, you can skip this step. If you are using screen door mesh, cut out strips 10 inches (25 cm) wide and cut into 8 inches (20 cm) sections and fold in half. Use the glue gun, needle and thread or soldiering iron to seal two sides. Leave one end open so you can put the leaves in.

Once you have the leaf bags made, go outside and fill them with leaves. Try to use freshly fallen leaves and collect only the leaves from under the trees where you will be leaving your bags. If the leaves are too dry, you can wet them with a bit of water to get them into the bags without crumbling. The grocery store bags will have larger openings, so you might want to use bigger leaves.

Close the bags with hot melt glue, or by sewing or tying them shut. Place the leaf bags outside in a place where you can safely retrieve them. You might consider marking the bags with sticks in the ground or tying the bags to brightly colored tent pegs shoved into the ground.

Now you have to be patient. Check the bags roughly every month and see how they are faring. Leave them under the trees until next year and then be sure to collect them. Open the bags into a tray or pan and sort through the contents. What do you think you might find?

Other fun activities for fall leaf drop season are to put the leaves back on the tree and exploring fall color.

Do you know what kind of tree this is?

We’d love to hear what you find in your leaf bags.

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