Posts tagged Science

863 posts tagged Science

Gray fox and opossum - October Afternoon, Eastern Tennessee
A gray fox (ground)and a Virginia opossum (tree) are feeding upon ripe persimmons in Great Smoky Mountains National Park. Both animals are omnivores—they eat plants and animals. 
Both species are nimble tree climbers as well, yet have different adaptations for the task. Gray foxes shinny up trunks by gripping with their forelimbs while pushing with their hind paws. Opossums climb with the help of an opposable toe on each hind foot, as well as a prehensile or “grasping” tail.
The gray fox and Virginia opossum may look similar, but they represent two fundamentally distinct groups of mammals.
Foxes are placentals, like humans and most mammals today. Mothers have long pregnancies, nourishing their fetuses through a placenta. Newborns are relatively large and robust, sometimes walking within hours.
Opossums are marsupials, a group that also includes kangaroos and koalas. Pregnancies are so short that newborns are barely more than embryos. The tiny babies crawl to a teat using strong forelimbs and nurse for many weeks to complete development. Like many marsupials, Virginia opossums protect their young with a pouch, or marsupium.
This diorama is located in the Bernard Family Hall of North American Mammals. 

Gray fox and opossum - October Afternoon, Eastern Tennessee

A gray fox (ground)and a Virginia opossum (tree) are feeding upon ripe persimmons in Great Smoky Mountains National Park. Both animals are omnivores—they eat plants and animals. 

Both species are nimble tree climbers as well, yet have different adaptations for the task. Gray foxes shinny up trunks by gripping with their forelimbs while pushing with their hind paws. Opossums climb with the help of an opposable toe on each hind foot, as well as a prehensile or “grasping” tail.

The gray fox and Virginia opossum may look similar, but they represent two fundamentally distinct groups of mammals.

Foxes are placentals, like humans and most mammals today. Mothers have long pregnancies, nourishing their fetuses through a placenta. Newborns are relatively large and robust, sometimes walking within hours.

Opossums are marsupials, a group that also includes kangaroos and koalas. Pregnancies are so short that newborns are barely more than embryos. The tiny babies crawl to a teat using strong forelimbs and nurse for many weeks to complete development. Like many marsupials, Virginia opossums protect their young with a pouch, or marsupium.

This diorama is located in the Bernard Family Hall of North American Mammals

This month marks the publication of Opulent Oceans: Extraordinary Rare Book Selections from the American Museum of Natural History Library (Sterling Signature, 2014), the third in a series showcasing the spectacular holdings of the Rare Book Collection in the Museum Library.
Written by Curator Melanie L. J. Stiassny, the book includes essays about pioneering biologists who studied marine life, and showcases a variety of scientific illustrations that brought new discoveries to a growing audience of experts and laypeople alike.
We recently spoke with Dr. Stiassny, who is Axelrod Research Curator in the Department of Ichthyology, about her experiences researching the book.
Q: Are there any particular favorites among the scientists you feature?
A: One of my favorites is Johann David Schöpf (1752–1800) who was an iconic example of a polymath, adventurer, and humanitarian. He was a medical doctor, as so many of them were, fascinated by natural history, paleontology, weather patterns, botany, geology—everything. His travels through post-Revolutionary America were an amazing feat of courage and discovery.
Q: What surprised you in preparing the book?
A: I could not find a single volume in the Museum’s Rare Book Collection containing the work of a female marine naturalist. I did manage to find a few women doing great stuff but unacknowledged by the scientific community of their time. There was one botanist, William Henry Harvey (1811–1866), who went to great pains to single out and thank the women who had contributed to his work. He is a favorite too!
Q: What was your personal take-away?
A: Tremendous respect for the extraordinary courage and commitment of these early marine explorers. When I am in the Congo, we have satellite phones. We go to a cybercafe once a month. They were out there for years with no communications, suffering diseases, shipwrecks—and think what they did. They traveled, wrote, did so much, and then died at 30 or 40. Schöpf was 48! I’m in awe of what they accomplished. I also felt a camaraderie with their excitement in discovery and drive to understand the natural world. That mission and excitement is very much the same for curators today. The great majority were with big museums. Their names are on the specimen jars; our names are on the jars. There’s remarkable continuity, despite our advanced technology. They had the same driving force. The same camping out under the stars.
Read the full Q&A on the Museum blog, and pick up your own copy of Opulent Oceans!

This month marks the publication of Opulent Oceans: Extraordinary Rare Book Selections from the American Museum of Natural History Library (Sterling Signature, 2014), the third in a series showcasing the spectacular holdings of the Rare Book Collection in the Museum Library.

Written by Curator Melanie L. J. Stiassny, the book includes essays about pioneering biologists who studied marine life, and showcases a variety of scientific illustrations that brought new discoveries to a growing audience of experts and laypeople alike.

We recently spoke with Dr. Stiassny, who is Axelrod Research Curator in the Department of Ichthyology, about her experiences researching the book.

Q: Are there any particular favorites among the scientists you feature?

A: One of my favorites is Johann David Schöpf (1752–1800) who was an iconic example of a polymath, adventurer, and humanitarian. He was a medical doctor, as so many of them were, fascinated by natural history, paleontology, weather patterns, botany, geology—everything. His travels through post-Revolutionary America were an amazing feat of courage and discovery.

Q: What surprised you in preparing the book?

A: I could not find a single volume in the Museum’s Rare Book Collection containing the work of a female marine naturalist. I did manage to find a few women doing great stuff but unacknowledged by the scientific community of their time. There was one botanist, William Henry Harvey (1811–1866), who went to great pains to single out and thank the women who had contributed to his work. He is a favorite too!

Q: What was your personal take-away?

A: Tremendous respect for the extraordinary courage and commitment of these early marine explorers. When I am in the Congo, we have satellite phones. We go to a cybercafe once a month. They were out there for years with no communications, suffering diseases, shipwrecks—and think what they did. They traveled, wrote, did so much, and then died at 30 or 40. Schöpf was 48! I’m in awe of what they accomplished. I also felt a camaraderie with their excitement in discovery and drive to understand the natural world. That mission and excitement is very much the same for curators today. The great majority were with big museums. Their names are on the specimen jars; our names are on the jars. There’s remarkable continuity, despite our advanced technology. They had the same driving force. The same camping out under the stars.

Read the full Q&A on the Museum blog, and pick up your own copy of Opulent Oceans!

Autumn is in full swing, and the Northeast US is a riot of colors. What causes this seasonal change? We’ve got the answers to all of your fall foliage questions here:
WHERE DO LEAF COLORS COME FROM?
Leaves are green in the summer because they contain a great deal of the pigment chlorophyll. Chlorophyll is necessary for the process of photosynthesis, which plants use to make food.
Chlorophyll is not the only pigment in leaves, but during the summer there’s so much of it that no other colors can be seen. Leaves also contain carotenoids—yellow, orange and brown pigments that give color to such foods as carrots and bananas. In the fall, some leaves produce red pigments called anthocyanins, which are also found in fruits like cranberries and blueberries. 
WHAT TRIGGERS A LEAF TO CHANGE COLOR?
As autumn approaches, days become shorter and nights grow longer. Trees respond to the decrease in sunlight by slowing down production of the green pigment chlorophyll. As the amount of chlorophyll drops, yellow, orange and brown pigments (carotenoids) become visible. In some trees, dwindling light levels cause other changes inside the leaf. For instance, the concentration of sugars often goes up, which causes the formation of red pigments (anthocyanins).
DOES WEATHER AFFECT AUTUMN COLORS?
Only a little bit. Although some people assume that leaves change color in response to cooler weather, it’s really the shorter days of fall that signal to trees that it’s time to prepare for winter. But weather does affect the intensity of leaf color. Seasonably warm and sunny fall days combined with cool (but not freezing) nights seem to produce the most stunning autumn colors. In addition, fall colors can be delayed by a severe summer drought.
DO LEAVES ON ALL TREES CHANGE COLOR?
No. Trees like pines, spruces and firs are “evergreens”—their leaves are always green. These trees generally have tough needle-shaped leaves that can withstand cold weather. In fact, individual leaves on evergreens can stay on the tree for several years.
ARE CERTAIN COLORS ASSOCIATED WITH A PARTICULAR KIND OF TREE?
Yes. The chart below lists some common trees and their typical fall leaf colors.
 ASPEN:                Golds
BEECH:               Yellows and Tans
DOGWOOD:        Deep Reds
ELM:                    Browns
HICKORY:            Golds
OAK:                   Reds and Browns
RED MAPLE:        Bright Reds
SOURWOOD:       Deep Reds
SUGAR MAPLE:    Orangish Reds
Can’t get enough fall foliage? Check out our Pinterest board Autumn at the Museum. 

Autumn is in full swing, and the Northeast US is a riot of colors. What causes this seasonal change? We’ve got the answers to all of your fall foliage questions here:

WHERE DO LEAF COLORS COME FROM?

Leaves are green in the summer because they contain a great deal of the pigment chlorophyll. Chlorophyll is necessary for the process of photosynthesis, which plants use to make food.

Chlorophyll is not the only pigment in leaves, but during the summer there’s so much of it that no other colors can be seen. Leaves also contain carotenoids—yellow, orange and brown pigments that give color to such foods as carrots and bananas. In the fall, some leaves produce red pigments called anthocyanins, which are also found in fruits like cranberries and blueberries. 

WHAT TRIGGERS A LEAF TO CHANGE COLOR?

As autumn approaches, days become shorter and nights grow longer. Trees respond to the decrease in sunlight by slowing down production of the green pigment chlorophyll. As the amount of chlorophyll drops, yellow, orange and brown pigments (carotenoids) become visible. In some trees, dwindling light levels cause other changes inside the leaf. For instance, the concentration of sugars often goes up, which causes the formation of red pigments (anthocyanins).

DOES WEATHER AFFECT AUTUMN COLORS?

Only a little bit. Although some people assume that leaves change color in response to cooler weather, it’s really the shorter days of fall that signal to trees that it’s time to prepare for winter. But weather does affect the intensity of leaf color. Seasonably warm and sunny fall days combined with cool (but not freezing) nights seem to produce the most stunning autumn colors. In addition, fall colors can be delayed by a severe summer drought.

DO LEAVES ON ALL TREES CHANGE COLOR?

No. Trees like pines, spruces and firs are “evergreens”—their leaves are always green. These trees generally have tough needle-shaped leaves that can withstand cold weather. In fact, individual leaves on evergreens can stay on the tree for several years.

ARE CERTAIN COLORS ASSOCIATED WITH A PARTICULAR KIND OF TREE?

Yes. The chart below lists some common trees and their typical fall leaf colors.

 ASPEN:                Golds

BEECH:               Yellows and Tans

DOGWOOD:        Deep Reds

ELM:                    Browns

HICKORY:            Golds

OAK:                   Reds and Browns

RED MAPLE:        Bright Reds

SOURWOOD:       Deep Reds

SUGAR MAPLE:    Orangish Reds

Can’t get enough fall foliage? Check out our Pinterest board Autumn at the Museum

This fearsome 17-foot-long Xiphactinus audax is ready for #FossilFriday!
Alive during the Late Cretaceous (about 85 million years ago), Xiphactinus and its relatives were large predators with strong jaws and many teeth. Xiphactinus swam in the great inland sea that covered most of North America at the end of the Age of Dinosaurs. This specimen was collected in Lane County, Kansas. 
Find Xiphactinus in the Hall of Vertebrate Origins. 

This fearsome 17-foot-long Xiphactinus audax is ready for #FossilFriday!

Alive during the Late Cretaceous (about 85 million years ago), Xiphactinus and its relatives were large predators with strong jaws and many teeth. Xiphactinus swam in the great inland sea that covered most of North America at the end of the Age of Dinosaurs. This specimen was collected in Lane County, Kansas. 

Find Xiphactinus in the Hall of Vertebrate Origins

The Explore21 team 
© AMNH/P. Sweet
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A sleeping platform in the team’s base camp. 
© AMNH/P. Sweet
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The team’s base camp is in a site known as Wigilia.
© AMNH/P. Sweet
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A typical camp breakfast consists of crackers with peanut butter, jam, or other toppings.
© AMNH/P. Sweet
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Expedition Report, Day 10: Biscuits, Frog Calls, & Scenes from Camp Life in Papua New Guinea

[Filed October 12]: We’ve now been at our base camp, in a site known to the local people as Wigilia, for 10 days. Aside from a few scattered “gardens,” clearings for growing kaukau and taro, this is untouched bush.

Camp life has settled into a routine. Breakfast is “Hardman Bisket” a 2-by-4-inch thick cracker with peanut butter. Lunch is usually instant noodles or perhaps boiled kaukau with tuna. The big meal of the day is always rice with a sauce of tinned mackerel, or corned beef mixed with more instant noodles. Sadly, all the hot sauce is gone!

The vertebrate surveys are proceeding well, and we feel satisfied that we have made a fairly complete inventory of the local fauna. Birdlife is diverse: we wake up to the bizarre calls of the Black Sicklebill, a bird of paradise, and on the ridge above camp we have found the maypole bowers of MacGregors’s Bowerbird. At night, the screams of Cuscus, arboreal marsupials, and many species of frog fill the chilly night air. 

Read the full dispatch from the Explore21 team in Papua New Guinea

Happy #NationalFossilDay! Can you tell which of the above are dinosaur teeth? Below are the answers.
Clockwise from top:
Tyrannosaurus rex tooth (Late Cretaceous, western US) 
Tyrannosaur tooth (Late Cretaceous, Judith River, MT) 
Rugose coral (Middle Devonian, Falls of the Ohio, Clarksville, Indiana) 
Rugose coral (Paleozoic, locality unknown) 
Ornithomimid toe claw (Late Cretaceous, western US)
Rugose coral (Paleozoic, locality unknown)
Tyrannosaur tooth (Late Cretaceous, Judith River, MT) 
Rugose coral (Paleozoic, locality unknown)
Theropod tooth (Late Cretaceous, Ojo Alamo, NM) 
Tyrannosaur toe claw (Late Cretaceous, western US). 
All are fossils except, technically, the T. rex tooth at the top, which is actually a cast of a real tooth. The rugose corals (also known as solitary or horn corals) are very often mistaken for dinosaur teeth but are older than the oldest dinosaurs, having gone extinct around 250 million years ago (the oldest known dinosaurs are around 230 million years old).
Learn more on the Museum’s Division of Paleontology website. 

Happy #NationalFossilDay! Can you tell which of the above are dinosaur teeth? Below are the answers.

Clockwise from top:

  • Tyrannosaurus rex tooth (Late Cretaceous, western US)
  • Tyrannosaur tooth (Late Cretaceous, Judith River, MT)
  • Rugose coral (Middle Devonian, Falls of the Ohio, Clarksville, Indiana)
  • Rugose coral (Paleozoic, locality unknown)
  • Ornithomimid toe claw (Late Cretaceous, western US)
  • Rugose coral (Paleozoic, locality unknown)
  • Tyrannosaur tooth (Late Cretaceous, Judith River, MT)
  • Rugose coral (Paleozoic, locality unknown)
  • Theropod tooth (Late Cretaceous, Ojo Alamo, NM)
  • Tyrannosaur toe claw (Late Cretaceous, western US). 

All are fossils except, technically, the T. rex tooth at the top, which is actually a cast of a real tooth. The rugose corals (also known as solitary or horn corals) are very often mistaken for dinosaur teeth but are older than the oldest dinosaurs, having gone extinct around 250 million years ago (the oldest known dinosaurs are around 230 million years old).

Learn more on the Museum’s Division of Paleontology website

One of the tree frogs the team has spotted so far at camp is from the genus Litoria.
©AMNH/C.Raxworthy
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Eight days into survey work in Papua New Guinea, herpetologist Chris Raxworthy is finding great species diversity—and getting soaked to the bone.
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Along with 18 amphibians, the team has turned up three skinks, genus Sphenomorphus. 
©AMNH/C.Raxworthy
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Another tree frog is from the Nyctimystes genus, commonly known as  big-eyed tree frogs.
©AMNH/C.Raxworthy
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This frog, from the genus Barygenys, was among the 18 amphibian species the team has found at high elevation.
©AMNH/C.Raxworthy
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Day surveys focus on reptiles and have so far yielded one snake species, from the genus Tropidonophis.
©AMNH/C.Raxworthy
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This fall, a team of vertebrate specialists from the Museum is heading out to one of the most remote areas in the world in search of new species and specimens on the Explore21 Papua New Guinea expedition. In this dispatch, filed October 10, herpetologist Chris Raxworthy sends this report from the field:

We are now eight days into our biological survey of the high elevation camp at Malaumanda: eight days of rain every day, in a forest that feels like a super-saturated giant green sponge where thick moss grows on everything. 

Grab a clump of moss, and you can squeeze half a cup of water from it. Every footstep in the forest makes a sucking noise, as your boots sink in the peaty soil. The forest that surrounds us is also staggeringly beautiful: a sea of broccoli trees when viewed from above, that must now stretch unbroken like a giant sea for many, many miles in all directions. And this forest is now beginning to reveal its amazing wildlife to us. 

My survey work is focused on the amphibians and reptiles. Brett warned me about reduced species diversity at this camp, because we are already so high at 1,800 meters elevation, yet we have already found 22 species. These include one snake, three skinks, and 18 frogs, including beautiful tree frogs and strange narrow-mouthed toads.  Because this region has not been previously surveyed, some of these may represent new species. 

Read the full post on the Museum blog

This specimen at the Museum is the only real fossil Deinonychus, a non-avian maniraptor, on display in the world.
With its sickle claws and sharp teeth, Deinonychus was likely a formidable predator. Its extremely advanced wrists and shoulders provide strong additional evidence for the hypothesis that birds are a kind of dinosaurs.
jnsilva photographed this fossil in the Hall of Saurischian Dinosaurs.

This specimen at the Museum is the only real fossil Deinonychus, a non-avian maniraptor, on display in the world.

With its sickle claws and sharp teeth, Deinonychus was likely a formidable predator. Its extremely advanced wrists and shoulders provide strong additional evidence for the hypothesis that birds are a kind of dinosaurs.

jnsilva photographed this fossil in the Hall of Saurischian Dinosaurs.

Eastern Cottontails - October, Ithaca, New York
Eastern cottontails thrive in brambles bordering open fields, and they are fond of farms, gardens and other green areas tended by people. While browsing in a pumpkin patch, these two rabbits are using their large eyes and pivoting ears to scan their surroundings for danger.
Startled cottontails will bolt for cover, showing the puffy white fur on the underside of their tails. The white flash seems to advertise that the speedy rabbits are off and running. For predators, it’s too late for a surprise attack. Some may give the cottontails up for lost and hunt for other prey.
Cottontails feed at dawn and dusk, resting during the day and night in simple hollows in the grass called forms. Females build separate nests for their young by digging shallow holes and lining them with grass, leaves and tufts of their own soft fur. Female cottontails bear up to 35 young each year!
This diorama is located in the Museum’s Hall of North American Mammals. 

Eastern Cottontails - October, Ithaca, New York

Eastern cottontails thrive in brambles bordering open fields, and they are fond of farms, gardens and other green areas tended by people. While browsing in a pumpkin patch, these two rabbits are using their large eyes and pivoting ears to scan their surroundings for danger.

Startled cottontails will bolt for cover, showing the puffy white fur on the underside of their tails. The white flash seems to advertise that the speedy rabbits are off and running. For predators, it’s too late for a surprise attack. Some may give the cottontails up for lost and hunt for other prey.

Cottontails feed at dawn and dusk, resting during the day and night in simple hollows in the grass called forms. Females build separate nests for their young by digging shallow holes and lining them with grass, leaves and tufts of their own soft fur. Female cottontails bear up to 35 young each year!

This diorama is located in the Museum’s Hall of North American Mammals

Meet Dr. Melanie Hopkins, an assistant curator in the Division of Paleontology at the Museum.

Dr. Hopkins is working to unlock the history of the evolution of animals over vast stretches of geologic time. For her, the key is trilobites—extinct arthropods that lived for almost 300 million years until 250 million years ago, when Earth experienced the largest mass extinction in its history. Her research takes her out into the field but also into the Museum’s collections, which include an estimated 400,000 specimens and where new discoveries wait to be made.

Meet more Museum curators in this video series

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Lonesome George, the Galapagos tortoise who was the last of his kind, is on view at the Museum through January 4, 2015. Below is a quick rundown of everything you need to know about Lonesome George.

Species: Last documented member of Chelonoidis abingdoni, native to Pinta Island

Age: Thought to be more than 100 years old

Diet: Cactus, shrubs, grasses, and broad-leaved plants

Turtle vs. tortoise? Tortoises are turtles that live exclusively on land.

Did you know? Lonesome George—the lone tortoise of his species for at least 40 years—was named after a famous 1950s American TV comedian, George Gobel, who called himself “Lonesome George.”

Notable traits: An extremely long neck and a “saddle-backed” shell that rises slightly in front, like a saddle

Weight: About 165 lbs (75 kg); males of various species of Galapagos tortoises can exceed 660 lbs (300 kg) and are the largest living tortoises

Discovery: In 1971, a Hungarian scientist spotted Lonesome George on Pinta Island. The discovery surprised researchers who thought Pinta Island tortoises were already extinct. A year later, George was taken to the Tortoise Breeding and Rearing Center on Santa Cruz Island, where he lived for the next 40 years. 

Saving Lonesome George: Staff at the Galapagos National Park and Charles Darwin Research Station tried repeatedly to mate Lonesome George with females from closely related species. Those efforts failed, but a new strategy to revive the species is underway. The discovery of hybrid tortoises partially descended from Pinta Island tortoises on Isabela Island, where whalers or pirates likely moved them long ago, provides the opportunity for establishing a breeding colony whose young will initiate the recovery of a reproductive population on Pinta.

Can’t get enough Lonesome George info? Head to the Museum’s website for more.

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