Watching a large group of animals migrating together can be quite a magical sight. Have you ever wondered why animals make the effort to travel such long distances? Or how animals know when and where to go without clocks, calendars or a GPS? Take this quiz to learn some answers.
What is animal migration?
when animals move to a new country
when animals cross a body of water
when a species moves from one place to another
Animal migration occurs when an animal species moves from one place of another.
What is the timing of animal migration often connected to?
both of the above
Migrations are usually related to weather changes, feeding patterns or mating and breeding patterns. However, irruptive migrations don't follow any pattern and nomadic species tend to move places simply when the food supply has run out in their current location.
Removal migration is when a species can no longer remain in its habitat, due to a drastic change in environment or climate, forcing the species to find a new home. Humans may be the cause of a removal migration by draining swamplands or cutting down forests.
What alters the dry-season migration of African wildebeests?
Wildebeests have an irregular migration pattern, as do many animals, which depends upon water. When their water sources dry up, the wildebeests move on to find more water. Their migration may be altered by the sight of rainclouds and sound of thunder.
Why have salmon populations declined over the past years?
because of global warming
because of human interference
Salmon are born in rivers and then migrate to the sea as adults. When they are ready to mate, salmon swim upstream, mate and lay eggs in the same place that they were born, to protect the young salmon from predators in the ocean. However, dams have been built over rivers that salmon migrate through, preventing salmon from breeding.
Why do whales migrate to the cold waters near the poles?
They like to mate in the cold.
They enjoy the feel of cold water.
They can find better food in cold water.
Whales find their favorite foods, such as krill, in cold waters. However, baby whales do not have enough blubber to insulate them against the cold waters, so whales return to warmer, tropical waters during the winter to give birth. Gray whales migrate more than 6,000 miles each way!
The whooping crane, the rarest bird in the U.S., almost became extinct, but has now recovered somewhat. What problem arose when it came to migration time?
The cranes didn't know where to go.
Cranes migrate by following older cranes who know the way. As the older cranes died off, the new cranes had no way of knowing how to get to eastern America. Since 2000, scientists wearing crane costumes have raised crane chicks to the sound of ultralight planes. At migration time, the cranes follow the "human crane" ultralight pilots to the migration site. Ten migrations have been successful so far and it is hoped the young cranes will learn the route and pass it on to their offspring.
How do animals in hibernation know when it is time to migrate?
They can't sleep anymore.
They get hungry.
Their fat reserves run out.
In hibernation, animals' fat reserves slowly drop due to lack of food, causing them to wake up and move on at migration time. This process has been tweaked over the years by evolution, so that animals have enough fat left to make the journey to more bountiful ground.
Some animals know it is time to migrate based on their body clock. What is the term for the clock used to determine migration times?
Animals, like humans, have a circadian rhythm and a circannual rhythm. Some animals use their circannual rhythm to determine when it is the time of year for migration, without using any other stimuli to indicate the time of year.
How do sooty shearwater birds make the migration journey easier?
They ride on each other's backs.
They can rest on water.
They ride wind currents.
Sooty shearwater birds are native to New Zealand but migrate during the winter to northern places as far as California, Japan and Alaska. It is thought that the birds ride massive wind currents to help them with the 40,000 mile round trip.
Why do species live in areas that are too cold for them in the first place?
They had to move to increase resources.
Some scientists believe that such animals used to live in warm places all year long. As their population grew and food became scarce, some of them ranged far away for food by moving to cooler places during the warmer months. When food grew scarce in the winter, they would move back to the warmer places.
What is fascinating about the migration of the monarch butterfly?
The butterflies do the trip individually.
The migration is longer than the lifespan of a butterfly.
These butterflies journey from North America to Mexico, over 1,000 miles away, but the actual migration lasts longer than the lifespan of a typical monarch butterfly. The butterflies that make the trip are able to slow down their metabolism to that they live long enough to reach their destination. Two or three generations of monarch butterflies will pass before the next group migrates. Yet, amazingly, the offspring know the route!
The butterflies double their population during migration.
How do animals gauge which direction to move toward?
by the sun
Some animals use the sun to navigate their migration route. It is believed that some birds can even travel at night using the sun to navigate them, by "reading" where the sun sets and using that to set their course.
Which animal uses the coast of North America to guide them on their migration route?
Landmarks are another way of navigating a migration route. Whales use the entire West Coast of North America to guide them. When they go south in the Pacific Ocean, they keep the continent on their left and when they head north they keep it on their right.
What substance was found in the brains of some animal species that helps them to migrate in the right direction?
A magnetic mineral called magnetite has been found in the brains of some animal species. It is thought that this may be the reason behind some animal species' ability to detect the Earth's magnetic field and use it to navigate their migration route.