Lesson 3: Birds & Mammals

Imagine leaving your home every year and traveling hundreds of miles to a completely different place, only to return home later in the year. As amazing as this sounds, this is exactly what many species of birds do in a process called migration.

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So why do birds migrate? The two main reasons are for food and breeding (reproduction.) Imagine a bird that lives in the Arctic. During the cold winter, the birds simply leave and fly to warmer locations. When summer returns, they return as well. Back in the Arctic, they are the first animals there to look for new food sources, giving them a huge advantage. What’s more, since there aren’t that many animals that can survive the winter, the birds face fewer predators. They can lay their eggs with less risk of them being eaten.

The most common kind of migration involves a bird flying from the North to the South in the winter, this is not the only type of migration. Some birds migrate horizontally, meaning they go from one coast to the other, where they find pleasant climates. Others migrate down mountains in the winter, since it’s colder the higher up a mountain you go. Some birds that don’t fly migrate on foot or by swimming.

Migrating birds do get some help. They use wind currents to help them fly faster while using less energy. Some large birds get lifted up by hot air rising. Birds also have extra fat reserves which provide them with energy, and often will stop for a few days to “re-fuel” (although some do fly non-stop). With this help, birds can migrate remarkable distances. The Arctic tern is the record holder, with an incredible 20,000 km journey from the North to the South Pole!

One of the most amazing things about bird migration is that no one ever teaches the bird how or where to migrate. Instead, birds rely on the location of the sun and stars, knowing which direction is North, and sounds and smells, like the smell of the ocean or the waves crashing against the shore, to complete their incredible journey.

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Dolphins have complex brains which scientists have discovered are developed enough in certain areas to handle higher-order thinking. Dolphins have shown by their behavior that they know who’s in their group, what status they have, which team they’re on, and each have individual quirks that make it unique from the others. In fact, when a scientist placed a mirror in a tank, the dolphin recognized himself, which made scientists think that perhaps dolphins may have a sense of self.

After a dolphin is specially trained, it has the ability to learn language. Trainers teach the dolphins to tell the difference between statements and questions using gestures and symbols, and they can reverse the order of the words to mean different things (syntax). And dolphins can tell not only the order of the words, but that the meaning has changed as well.

For example, these two sentences have exactly the same words, but in different order:

“Johnny bit the dog.”
“The dog bit Johnny.”

Although the words are exactly the same, the order that you place them in a sentence will give them two entirely different meanings, especially if you are Johnny!

So what does all this have to do with aliens?

Well, I met Dr. Laurence Doyle of the SETI Institute years ago in Mountain View, California, and he studies animal communication as he figures out new ways to detect intelligence in space. It’s a special kind of math that looks at how information is structured, and it’s based on how dolphins communicate with each other.

If you’ve ever heard the statement ‘Are we alone?’ Dr. Doyle answers: ‘No, we’re not alone. There are many animals communicating right here that we don’t understand.’

Scientists are searching for ways to detect alien signals by starting right at home with smart animals all around us. Dr. Doyle says: ‘We’ve been waiting (to hear from aliens) for years, but I thought, ‘We’re not ready!’ We can’t even speak to the intelligent animals on Earth.’

Cool Fact: Did you know that dolphins know what “none” and “zero” means?

Ever wonder what a dolphin trainer really does? These trainers not only train dolphins, but also whales, seals, sea lions, walruses and other marine mammals by using positive reinforcement (sometimes referred to “operant conditioning”). This means that when the animal does the right behavior, there’s a reward. Otherwise, no action or reward is taken. Here’s a neat video that shows how dolphins and killer whales are trained for real:

Having feathers is one of the most distinct features of birds. In fact, birds are the only living group of animals that have feathers. Not all feathers are the same however. Take a walk, find some feathers, and explore what they do!

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1. Find an area where birds are common. Go for a walk and collect as many feathers from the ground as many as you can.
2. Classify the feathers into groups as shown below:

a. Wing Feathers – These feathers will be firm and strong and have a hollow tube. The tube is light because it’s hollow, but also strong. Wing feathers have more feather on one side of the tube than the other. The side with more feather faces the body, so you can determine if the feather was on the left or right side
b. Tail Feathers – These feathers will be as strong as wing feathers, with the same hollow tube going down the center. Unlike wing feathers, however, these feathers will have equal amounts of feather on both sides of the tube
c. Body Feathers – These feathers will not be as strong wing or tail feathers. They will be more flexible and colorful.

d. Down Feathers – These will be the softest, most flexible feathers of all.

What’s Happening: Each feather looks different because it has a different purpose. Wing and tail feathers assist in flying and gliding. Body feathers give the bird color, which can help them in blending in for camouflage or standing out to attract a mate. Down feathers provide insulation. They are under the body feathers and keep heat in or out depending on the weather.

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By completing a dissection, you can see firsthand the anatomy of an animal. Dissecting a roasted chicken (yes, the same kind that you eat) will allow you to investigate the skin, muscle, and bones of this bird.

So, if you’re interested in seeing what allows a chicken to run, fly, and survive, go out to the grocery store and grab some chicken!

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1. Observe a roasted chicken. Make note of the skin. The skin provides the chicken with protection, just like it does in human beings.
2. Note: The next steps require a knife and scissors. Be sure to get parent permission before doing this. Now, with a knike, cut the skin from the back to the front along the sternum bone, which you should be able to feel along the top of the chicken.

3. Pull the skin back to expose the muscle (the part you eat).

4. With a fork or with your fingers, remove the muscle. Notice the amount of muscle present and the fact that it connects to the sternum, or breastbone. This muscle also attaches to the wing, and provides the wing with the muscle it needs for flight.

5. Remove a leg from the whole chicken. Cut the skin to expose muscle. Pull muscle out from the top half of the leg. The single bone you see is the femur. As you look at the top of the bone, notice the circular looking structure. This is part of the ball-and-socket joint that connects the femur and hip.

6. Carefully remove the muscle from the lower half of the leg, exposing the larger tibia and smaller fibula bones. Also notice that there is quite a bit of muscle attached to the leg. Remember that chickens run more than they fly.

Why is this important: By looking at the muscle and bones of the chicken, you can learn a great deal about the animal. It is clear that both flight and running are important for chickens. It is also interesting to note the ways in which chicken anatomy is similar to human anatomy. Both animals have sternums, a femur, a tibia, and a fibula. If you’d like, you can dissect the wing in the same way as the leg, and observe the same bones as the human arm.

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Marsupials are characterized by the presence of a pouch in the female. The pouch contains the mammary glands, which nourish the young. The offspring of marsupials remain in the pouch until they are able to survive on their own. The most well known marsupials are probably kangaroos and koalas, but there are a number of other marsupials, many from Australia.

The thylacine (tasmanian tiger) looked a lot like a short-haired dog combined with a kangaroo. Some folks say that it looked similar to a hyena. The stripes on the rump faded as the animal aged.

There was some sexual dimorphism (the males were slightly larger than females). Normally in marsupials, the pouch opens toward the head of the animal. The female had a pouch that opened to the rear (toward the tail). The thylacine was able to open its jaws very wide – nearly 120 degrees – to show off its 46 sharp teeth.

Emperor and Adelie penguins are two species of this flightless bird that live in the Antarctic. Adelies spend most of the year in the water. In October, spring begins in the southern hemisphere, including in the South Pole where Adelies live, and these penguins come onto the land to lay their nests, mate, and raise chicks. The nest of the Adelie is lined with pebbles, and the penguins are very careful about the pebbles they choose. A good pebble can lead to fights if several penguins want it, and a penguin will steal another penguin’s pebble if they are not paying attention.

Male and female Adelie’s work together incubating the eggs and raising the chicks. The female lays two eggs and the male takes the first turn incubating them. After they hatch, in about 35 days, one parent watches them while the other gets food. As the chicks grow, they are left in groups called crèches, so that both parents can hunt for them. By February, as it is getting close to fall in the South Pole, the chicks have fully developed feathers and are ready to leave the land and go onto the ice.

Emperor penguins are the tallest, heaviest, and deepest diving penguins. They also are the only penguins who raise their young during Antarctic winters. The penguins come out of the sea in March and walk, sometimes great distances, to breeding grounds. Most colonies breed on ice, although a few do so on the ground.

In May or early June, the female lays a single egg and transfers it to her mate. The male incubates the egg for two months in a pouch called the brood pouch. Many males will huddle together, taking turns being on the inside and outside, to stay warm. During this time, the females go off to hunt. Like the Adelies, males and females take turns protecting and providing food for the newborns until they get old enough to be left alone while both parents hunt. In December or January, they return to the sea.

Emperors are well designed for their difficult tasks, including surviving the cold, going without food for long periods of time, and making many hard trips to and from the sea. If they go so deep in the water that the pressure becomes greater than their lungs can handle, they can collapse their lungs and slow down their heart rates to save oxygen. They also store additional oxygen in muscle tissue. Research about this oxygen storage ability may help human stroke victims, who also suffer from a lack of oxygen.

Global warming presents severe problems for the Adelie and Emperor penguins. Melting of the ice in Antarctica will reduce the amount of space the penguins have to hunt and live for most of the year. Rising temperatures will also bring more rain and liquid water to Antarctica, which is currently the driest place on Earth. Melted water can destroy the pebble-protected nests of the Adelies. In the Western Antarctic peninsula, where global warming has had the greatest effect, penguin populations have decreased by 80%.