Highlights of the Natural History Museum: the Ocean

The Smithsonian National Museum of Natural History is located on Constitutional Avenue in Washington D. C. The museum has an enormous collection of exhibits and artifacts. Inquisitive visitors can learn about the Earth, oceans, human origins, mammals and reptiles, birds and insects, dinosaurs, fossils, geology, gems and minerals. Exhibitions in the museum are arranged in a way that the visitor can travel in time from the inception of the Earth up to present.  Animals from every continent are introduced.  Scientists take the visitors on a journey to the depth of the ocean floor with exhibits and videos. The museum is a treasure trove of scientific discoveries and research. It’s the result of  hard work and the efforts of many dedicated people, who went down to the bottom of the oceans, dug deep into the ground and turned lots of rocks to bring their findings and share them with people. Here are the highlights that we found the most interesting about the ocean.

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A magnificent African bush Elephant stands in the rotunda on the first floor. His trunk is up and also his tail, which according to the elephants’ body language most likely means: “Welcome to the museum.” He is the largest animal ever exhibited in a museum. His weight was 12 tons and his is 14 feet tall.

The Ocean Hall is also on the first floor. The first thing that draws attention when entering the Ocean Hall is a huge North Atlantic Right Whale, soaring under the ceiling. Her name is Phoenix, which means “reborn.” She got her name after a dramatic event, which happened in her life. She was spotted for the first time by scientists on January 14, 1987 off the coast of Georgia, when she was still a baby. She was swimming alongside her mother, Stumpy. Phoenix had her first calf in 1996, when she was nine years old. Her picture with the calf was taken off the coast of Florida. In August 1997 she got tangled in a fishing net off the coast of Canada, close to the Bay of Fundy. This almost cost her life, but she managed to free herself. However she got permanent scars on her head from the net. This was the dramatic event from which she got her name.  She was spotted again in May 1999 near Cape Cod in the Great South Channel.

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The next time Phoenix was seen was with her second calf in December 2004 close to Florida. In February 2004 Phoenix lost her mother, Stumpy, due to a collision with a ship off the coast of Virginia. Stumpy was pregnant with her sixth calf at the time of her death.

Phoenix has baleen, the plates in her upper jaw which helped her to catch food. Phoenix also has callosities, which are patches of rough skin, on her head. These skin patches look white because of whale lice living on them.

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Each whale has a distinct pattern of callosities, which helps scientists to recognize whales and keep track of them in the North Atlantic Right Whale catalog. Pictures of whales are taken from ships, airplanes and helicopters. Scientists make estimations about the size and weight of each whale based on these photos.

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Phoenix weighed about 1,900 pounds at birth. In 2000, when she was 13 years old, it was estimated that she was 43 feet long and 13 feet wide. Adult whales usually reach 140,000 pounds. Occasionally, scientists lose track of some whales. Some of the whales reappear, but some do not. The catalog helps to create a personal history of each whale.

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There are also three large skeletons hanging under the ceiling of the Ocean Hall. These species represents stages in evolution of the whale. The earliest, Maiacetus, lived 49 million to 40 million years ago. He had flipper like limbs and was able to live like seals and walruses, in the water and on the land. These creatures returned to land to mate and give birth.

 

Dorudons, who lived 38 million to 36 million years ago, became more adopted to live in the water. Their limbs got shorter, especially the hind limbs and toes, and their tails got longer which helped them propel themselves through the water.

 

Basilosaurus, who lived 40 million to 35 million years ago, had a long and strong elongated body with paddle like forelimbs and barely noticeable hind limbs. They had sharp teeth and were fast swimmers. They lived in the water and looked like reptiles. Only the remnants of their hind limbs indicate that they were mammals.

 

On display were many bizarre and unusual creatures, which lived at different depths in the ocean. These included a giant octopus, bubblegum coral and a giant squid, which was 36 feet long, but shrunk during preservation to 25 feet long.

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We got intrigued by huge and formidable jaws in an adjacent hall. They were the jaws of a Megalodon, an ancient predecessor of the Great White shark, but much bigger, stronger and more aggressive. Megalodon means “big tooth” and it was the biggest shark that ever lived in the ocean. They lived approximately 23 million to 5 million years ago, although some believe they went extinct 2.6 million years ago.

Scientists agree that the cause of their extinction was their inability to regulate their internal body temperature. They lived, hunted, bred and nursed their pups in coastal warm water all over the world. But during an Ice Age the water in the ocean receded and coastal warm water dried up. As a result whales, which were the main source of food for Megalodons, followed plankton and smaller prey to colder water closer to the Poles.  Megalodons had a choice to freeze or starve.

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Their maximum size reached 59 feet, which is 3 times longer than the Great White. The diameter of their jaws reached 7 feet and the length of a tooth was up to 7 inches. Before 1600 people thought that a Megalodon’s tooth was a dragon tongue.

The fossils of their teeth were found everywhere, in Australia, New Zealand, Japan, Denmark, India, the U.S. and Croatia. But most of them were found in Central America, because during the Miocene era there was a seaway between North and South America. Megalodons bred and nursed their pups in the warm coastal water of the seaway. Lots of Megalodons’ juvenile teeth were found of the coast of Panama. Juvenile Megalodons were about 20 feet long, the size of an adult Great White shark. During an Ice Age these breeding grounds and nurseries disappeared, which also contributed to the extinction.

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At one time Megalodons coexisted with Great White sharks, but the Great White hunted in cooler water closer to the Poles, where seals and walruses lived. They also had different hunting tactics. While Great White sharks attack their prey from the bottom, bites them, and waits until their prey bleed to death, Megalodons simply bit their prey by the back bone. Their bite was so strong that it crushed the prey bones and vital organs. Megalodons ate 2,500 pounds of food per day.  They had a great appetite!

Also on display is the history of evolution from the inception of the Earth 4.6 billion years ago.

Life on Earth started from one significant event, which happened about 3.5 billion years ago. It was the Great Oxygenating event due to cyanobacteria, which lived in the shallow coastal water. The atmosphere and the ocean were filled with carbon dioxide and there were no oxygen breathing organisms on the planet.

Cyanobacteria produced oxygen in a process called photosynthesis, using carbon dioxide, water, and sunlight.  There was lots of iron dissolved in the water of the ocean, but after reacting with oxygen the iron formed red colored iron oxide and settled to the bottom of the ocean. As a result sedimentary rocks were created.   These are called banded iron formations. When water could not hold any more oxygen, oxygen then went above the surface of the ocean and into the air and oxygenated the atmosphere of the Earth. This process was completed about 2.4 billion years ago. After the ocean and the air got oxygenated the evolution of oxygen breathing organisms became possible in the ocean and on the land.

Stromatolite
Stromatolite

Cyanobacteria are responsible for building up layers of sedimentary rock in the shapes of mounds, columns and sheets, called stromatolites. The oldest stromatolites are 3.7 billion years old and are found in Greenland. Stromatolites are also found in shark Bay in Western Australia, in Chile, In Brazil, and in the Mexican desert.

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There is also a story of how all five extinction events affected life on Earth. It is a display of when and why these extinctions happened and which species managed to survive. As an example, the most devastating extinction happened 255 million years ago, at the end of the Permian period. During this extinction event, 96% of all species were whipped out. It happened due to massive volcanic eruptions in Siberia. The concentration of methane and carbon dioxide in the atmosphere and in the ocean rose.  The ocean acidified so much that even corals died out. Smoke and volcanic ash filled the air.

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The fifth extinction happened 66 million years ago, when dinosaurs went extinct. It happened when a giant asteroid 10 km in diameter struck the Earth off the coast of the Yucatan Peninsula. During this event 76% of the existing species disappeared.

Placoderm
Placoderm

There is also a bizarre looking ancient fish, called Placoderm, which had armored plates protecting her head and thorax. Placoderms lived during the Silurian period 443-419 million years ago and went extinct during the late Devonian extinction event. They were bottom dwellers, predators, and are believed to use their jaw bones in place of teeth. Their armor protected them from other predators, such as arthropods, which had pincers like crabs and sea scorpions.

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There is a beautiful ancient ammonite, a mollusk, related to Nautiluses. They evolved during the Devonian period, 417 million years ago and went instinct 66 million years ago, when dinosaurs died out.

There is also an interesting movie that can be watched in the Ocean Explore Theater. Scientists went to the depth of the ocean, took pictures and videos of different species living at the different levels of a water column. We learned that only 5 % of the ocean has been studied and scientists study the Ocean not because they know something, but because they don’t know.

 

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