Animals that were oceans apart are nowtogether, due to melting Arctic ice

A research paper argues that climate change has led to more marine mammals, such as the Pacific white-sided dolphin

pictured above, changing their migratory behavior. Photo: NOAA via Wikimedia Commons

Animals have been showing up in strange places lately.

Gray whales live in the Pacific Ocean. In the spring of 2010, though, a single gray whale

was spotted in the Mediterranean Sea. It was the first time a gray whale was seen in the

North Atlantic in about 200 years.

How Did YOU Get HERE?

Other animals that live in the Pacific have been appearing in the Atlantic as well. Likewise,

creatures that live in the Atlantic Ocean have been seen in the Pacific.

What is going on? A group of scientists, led by a scientist named Seabird McKeon,

published a paper about the strange pattern. The paper was released on Nov. 30 in the

magazine Global Biology. It said that the reason animals are moving between the Atlantic

and the Pacific may have to do with climate change.

By Washington Post, adapted by Newsela staff on 12.20.15

Word Count 674

Between the Atlantic and Pacific are giant continents. Sea creatures cannot cross them.

Connecting the two oceans to the north is the Arctic Ocean. The Arctic is one of the

coldest places on earth. Because of how cold it is, big parts of the Arctic Ocean are

covered in ice.

Melting Ice Makes Travel Easier

The ice usually keeps animals from using the Arctic to move between the Atlantic and

Pacific oceans. Animals like whales and seals have difficulty getting through the ice. It gets

in the way of their swimming and can block them from coming up to breathe. Birds can fly

over the frozen ocean, but the ice prevents them from diving for fish.

These days, however, the ice is starting to melt. The climate is changing. Each year, the

earth is getting a little warmer. As the Arctic has warmed, ice has started melting. As a

result, passageways have opened up in the ice.

McKeon and his team believe that this has allowed certain animals to cross through the

Arctic, letting them move between the Atlantic and the Pacific. It is like a bridge has

opened up between two oceans that used to be separate. Animals that used to always be

apart can now mix. Scientists call this mixing "faunal exchange."

Studying "Faunal Exchange"

Many animals could become part of the faunal exchange. Birds such as Arctic terns,

common eiders, Atlantic puffins and short-tailed shearwaters may start to move between

the Atlantic and the Pacific. Beluga whales, ringed seals and Atlantic white-sided dolphins

may do so as well.

No one can say for sure what effects the faunal exchange will have. To get some idea,

though, McKeon and his team examined past examples of faunal exchange.

The Great American Biotic Interchange was a large faunal exchange. Several million years

ago a thin strip of land called the Isthmus of Panama formed between North and South

America. The new bridge allowed land animals to cross between the two continents for the

first time. As a result, animals from North America invaded South America. They beat out

many of the native animals there for food.

Watch Out For Killer Whales!

McKeon and his team also looked at what happened when killer whales moved into

Hudson Bay, a large body of water in Canada. As their name suggests, killer whales are

hunters. All of the sudden, the animals in Hudson Bay had to be on the lookout for a new

predator. Faunal exchange, in that case, altered the delicate balance of predators and

prey.

McKeon and his team argue that the current exchange between the Pacific and Atlantic

may have the same kinds of effects. It may lead to genetic changes as well. As animals

move to new territories, they mix with different kinds of animals. Sometimes these new

neighbors interbreed. New kinds of animals might be born as a result.

What Next?

At this point, scientists can only wait and see, and study. Most scientists seem to agree

that faunal exchange between the Pacific and Atlantic is already occurring. It seems like it

will only increase as more passages open up in the Arctic. The effects of faunal exchange,

however, remain to be seen.

Quiz

1 Which sentence from the section "How Did You Get HERE?" BEST explains why it is difficult for

animals like whales to move from the Pacific Ocean to the Atlantic Ocean?

(A) Other animals that live in the Pacific have been appearing in the Atlantic as

well.

(B) It said that the reason animals are moving between the Atlantic and the

Pacific may have to do with climate change.

(C) Between the Atlantic and Pacific are giant continents.

(D) Connecting the two oceans to the north is the Arctic Ocean.

2 Which sentence from the section "Watch Out For Killer Whales!" BEST helps you understand

why it can be bad when animals move between the Atlantic and the Pacific?

(A) Faunal exchange, in that case, altered the delicate balance of predators and

prey.

(B) McKeon and his team also looked at what happened when killer whales

moved into Hudson Bay, a large body of water in Canada.

(C) As animals move to new territories, they mix with different kinds of animals.

(D) New kinds of animals might be born as a result.

3 Read the sentence from the section "How Did YOU Get HERE?"

Likewise, creatures that live in the Atlantic Ocean have been seen in

the Pacific.

What is the meaning of the word "likewise" in the sentence?

(A) also

(B) because

(C) during

(D) never

4 Read the sentences from the section "Studying Faunal Exchange."

As a result, animals from North America invaded South America. They

beat out many of the native animals there for food.

How does the phrase "beat out" help you understand the meaning of the sentences?

(A) It tells you that the invading animals competed for the same food as the

native animals.

(B) It shows you how the invading animals attacked the native animals and ate

them for food.

(C) It lets you know that the invading animals got to the new land first before the

native animals.

(D) It shows you that the invading animals spent a lot of time with the native

animals.