1. Western Black WidowLatrodectus hesperus

    Spiders of the genus Latrodectus are found worldwide, and in North America, black widows are among the few species harmful to people. Still, they’re web builders that stay in their retreats day and night. If you see one outside its web, it’s likely a male in search of a female. That trip can end badly. As their name suggests, female black widows sometimes eat males after mating.

    Check me out: If I have a red hourglass on my underside, I’m a widow spider.

    Species Range: From Canada to the warmer regions of the western U.S. and south to Mexico

    Habitat: Terrestrial; crevices, including those in and around houses

    Should you worry? Yes. I’m shy and my fangs are small, but my venom is potent. Black widow venom contains powerful chemicals called neurotoxins, including one specific to vertebrates like us. Once injected, the venom may flood nerve endings with chemical signals, causing paralysis. 

    Unlikely to Bite: Black widows are shy and tend not to bite humans unless disturbed. Most bites involve such a small amount of venom that the victim survives.

    See the Western Black Widow in Spiders Alive! open now. 

  2. As the global climate changes, wild animals are shifting where they live—even beyond the protected areas that are crucial to their survival. This visualization highlights predictions and solutions for range shifts by an iconic species of North American wilderness, the wolverine.

    More Science Bulletins

  3. Bighorn Sheep - September Morning, Alberta, Canada
Stalwart symbols of mountain wilderness, a “bachelor band” of bighorn sheep stands before Mount Athabasca in the Canadian Rockies. Male sheep older than two years leave their mothers to follow a leading ram. Horn and body size determine rank, so the leader of this band is certainly the ram on the right. 
Equally sized males may duel to secure their rank. Rivals will repeatedly face off, charge and then crash horns until one loses balance and concedes. During the mating season, when rams fight for ewes, battles are even more violent. The collisions will echo across the ravines of the Rockies, and some contenders will even be pushed off the edge.
This diorama is located in the Bernard Family Hall of North American Mammals. 

    Bighorn SheepSeptember Morning, Alberta, Canada

    Stalwart symbols of mountain wilderness, a “bachelor band” of bighorn sheep stands before Mount Athabasca in the Canadian Rockies. Male sheep older than two years leave their mothers to follow a leading ram. Horn and body size determine rank, so the leader of this band is certainly the ram on the right. 

    Equally sized males may duel to secure their rank. Rivals will repeatedly face off, charge and then crash horns until one loses balance and concedes. During the mating season, when rams fight for ewes, battles are even more violent. The collisions will echo across the ravines of the Rockies, and some contenders will even be pushed off the edge.

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

  4. Hey everyone, the weekend is here! Flap your wings all the way to the Museum to learn about birds, migrations, and another flying phenom: pterosaurs!
Here are some cool links from the past week: 
Fossils of new squirrel-like species support earlier origin of mammals.
New research has identified drivers of rich bird diversity in the Neotropics.
Making a last dash to the beach? Search for these shells. 
Jack Tseng on the friends and foes you find in the Gobi desert. 
This week saw the last Super Moon of 2014.
The Margaret Mead Film Festival Returns this October!
Have a great weekend! 

    Hey everyone, the weekend is here! Flap your wings all the way to the Museum to learn about birds, migrations, and another flying phenom: pterosaurs!

    Here are some cool links from the past week: 

    Have a great weekend! 

  5. @karim.mustafa got up close with an Allosaurus in the Hall of Saurischian Dinosaurs #InsideAMNH
Learn more about the #InsideAMNH Instagram collaboration and follow along @amnh to see much more.

    @karim.mustafa got up close with an Allosaurus in the Hall of Saurischian Dinosaurs #InsideAMNH

    Learn more about the #InsideAMNH Instagram collaboration and follow along @amnh to see much more.

  6. A tabletop view in the Ichthyology collections area. Each jar and vial is filled with fish specimens from the research collection. Snapped by @samthecobra for #InsideAMNH.
Learn more about the #InsideAMNH Instagram collaboration and follow along @amnh to see much more.

    A tabletop view in the Ichthyology collections area. Each jar and vial is filled with fish specimens from the research collection. Snapped by @samthecobra for #InsideAMNH.

    Learn more about the #InsideAMNH Instagram collaboration and follow along @amnh to see much more.

  7. New Research Identifies Drivers of Rich Bird Diversity in Neotropics
An international team of researchers is challenging a commonly held view that explains how so many species of birds came to inhabit the Neotropics, an area rich in rain forest that extends from Mexico to the southernmost tip of South America. The new research, published today in the journal Nature and co-led by Brian Smith, an assistant curator in the Museum’s Division of Vertebrate Zoology, suggests that tropical bird speciation is not directly linked to geological and climate changes, as traditionally thought. Instead, it is driven by movements of birds across physical barriers such as mountains and rivers that occur long after those landscapes’ geological origins.
"The Neotropic zone has more species of birds than any other region on Earth," said Smith, who started this work as a postdoctoral researcher at Louisiana State University. "The unanswered question has been—how did this extraordinary bird diversity originate?"
Read the full story.

    New Research Identifies Drivers of Rich Bird Diversity in Neotropics

    An international team of researchers is challenging a commonly held view that explains how so many species of birds came to inhabit the Neotropics, an area rich in rain forest that extends from Mexico to the southernmost tip of South America. The new research, published today in the journal Nature and co-led by Brian Smith, an assistant curator in the Museum’s Division of Vertebrate Zoology, suggests that tropical bird speciation is not directly linked to geological and climate changes, as traditionally thought. Instead, it is driven by movements of birds across physical barriers such as mountains and rivers that occur long after those landscapes’ geological origins.

    "The Neotropic zone has more species of birds than any other region on Earth," said Smith, who started this work as a postdoctoral researcher at Louisiana State University. "The unanswered question has been—how did this extraordinary bird diversity originate?"

    Read the full story.

  8. New Research: Fossils of New Squirrel-like Species Support Earlier Origin of Mammals

    A research team led by paleontologists at the American Museum of Natural History and the Chinese Academy of Sciences have described three new small squirrel-like species that place a poorly understood Mesozoic group of animals firmly in the mammal family tree. The study, published today in the journal Nature, supports the idea that mammals originated at least 208 million years ago in the late Triassic, much earlier than some previous research suggests.

    The three new species—Shenshou lui, Xianshou linglong, and Xianshou songae—are described from six nearly complete 160-million-year-old fossils found in China. The animals, which researchers have placed in a new group, or clade, called Euharamiyida, likely looked similar to small squirrels. They weighed between 1 and 10 ounces and had tails and feet that indicate that they were tree dwellers.

    Based on the age of the Euharamiyida species and their kin, the divergence of mammals from reptiles had to have happened much earlier than some research has estimated. Instead of originating in the middle Jurassic (between 176 and 161 million years ago), mammals likely first appeared in the late Triassic (between 235 and 201 million years ago).

    Read the full story. 

  9. A Woefully Warm Forecast for Coral Reefs

    Record-setting global temperatures are increasingly stressing corals, leading to weakness and even death for these sensitive species. While some corals may be able to adjust to some level of heat stress over time, our actions to reduce emissions will largely determine how reefs fare in a climate increasingly inhospitable to their survival.

    Learn more about this Science Bulletin.

  10. A model in the Museum’s cephalopod display, photographed #InsideAMNH by djkrugman.
Learn more about the #InsideAMNH Instagram collaboration and follow along @amnh to see much more.

    A model in the Museum’s cephalopod display, photographed #InsideAMNH by djkrugman.

    Learn more about the #InsideAMNH Instagram collaboration and follow along @amnh to see much more.

  11. Get ready! Tonight, September 8, is the final Super Moon of 2014! 
The term Super Moon was coined in 1979 by an astrologer, who defined it as an event when a Full or New Moon occurs within 90% of its closest possible approach to Earth—closer than a threshold of about 224,851 miles. 
Did you know? Each Full Moon of the year has a name, mostly traceable to an era of agricultural living. Tonight’s full moon is the 2014 Harvest Moon. Traditionally this title is given to the Full Moon seen nearest the date of autumn’s beginning.

    Get ready! Tonight, September 8, is the final Super Moon of 2014

    The term Super Moon was coined in 1979 by an astrologer, who defined it as an event when a Full or New Moon occurs within 90% of its closest possible approach to Earth—closer than a threshold of about 224,851 miles. 

    Did you know? Each Full Moon of the year has a name, mostly traceable to an era of agricultural living. Tonight’s full moon is the 2014 Harvest Moon. Traditionally this title is given to the Full Moon seen nearest the date of autumn’s beginning.

  12. Jack Tseng, a postdoctoral fellow in the Division of Paleontology at the American Museum of Natural History, has been blogging from the field during a fossil-finding expedition in Inner Mongolia. In his final Fieldwork Journal, Jack talks about the friends and foes one encounters while looking for fossils. 

    On fossil smugglers:

    "Gobi fossils have become attractive to smugglers, and there has recently been a rise in black-market trade in these scientifically valuable finds. During one of our own expeditions, we left a large plaster-covered block containing late Miocene mammal fossils at the site of discovery for a later time, because it was too large to move with our available equipment. When we returned several months later to retrieve the block, we found that it had been hacked into pieces, with large portions missing."

    Read the whole Fieldwork Journal on the Museum blog

  13. Grizzly Bear - September Morning, Yellowstone National Park, Wyoming
You’d be wise to avoid stumbling upon this scene in the wild. Grizzly bears are unpredictable and may become aggressive if interrupted while eating or tending cubs. This mother is doing both: she’s showing her six-month-olds how to tear open a rotted pine for ants and grubs to eat. 
Did you know? Grizzly bears can grow to very different sizes depending on where they live. The nickname “grizzly” comes from the grizzled, or silver-tipped, hairs on their backs and shoulders.
Find this diorama in the Bernard Family Hall of North American Mammals. 

    Grizzly Bear - September Morning, Yellowstone National Park, Wyoming

    You’d be wise to avoid stumbling upon this scene in the wild. Grizzly bears are unpredictable and may become aggressive if interrupted while eating or tending cubs. This mother is doing both: she’s showing her six-month-olds how to tear open a rotted pine for ants and grubs to eat.

    Did you know? Grizzly bears can grow to very different sizes depending on where they live. The nickname “grizzly” comes from the grizzled, or silver-tipped, hairs on their backs and shoulders.

    Find this diorama in the Bernard Family Hall of North American Mammals. 

  14. Search for this scallop shell at the beach this weekend, and learn about many more shells that you may see along the way, over on the Museum blog!

    Search for this scallop shell at the beach this weekend, and learn about many more shells that you may see along the way, over on the Museum blog!

  15. On this day in 1977, Voyager 1 was launched into space carrying a “Golden Record” with the sounds of planet Earth. In 2012, it reached interstellar space. Timothy Ferris, the writer of the Hayden Planetarium Space Show Dark Universe script, produced the “Golden Record” and talks about it in this video.