mammalogy

Quickish painting of a Hyracodon, ancient relative of modern rhinos built for running. Done for a contest which I got mixed up on and submitted too late anyway. Used a mix of watercolor, gouache, and colored pencil. Paper shouldn’t be able to call itself watercolor paper if it clearly can’t handle water…

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A few of our favorite moments from the camera traps in Peru - the first captures the incredibly rare and elusive short-eared dog (Atelocynus microtis) making off with a massive fruit in its jaws (and it’s the first time this animal has been documented in this particular area!), and the second series shows a curious ocelot (Leopardus pardalis) in the middle of an early-morning prowl. 

Camera traps such as these provide untold insights on the biodiversity of an area. It may take a person years to report any solid evidence of these types of animals in a studied environment due to the difficulties of tracking creatures that have senses finely attuned to our presence in their territories. One of my favorite parts of being in Peru was simply knowing I was in a place inhabited by these magnificent species, despite the fact I would probably never get the chance to see them. 

To learn more about how mammalogists conduct surveys of these areas, check out our latest video checking out the bats of this region

.gifs by Tom McNamara!

Word of the day triple play: PLANTIGRADE, DIGITIGRADE, UNGULIGRADE

Three forms of terrestrial mammal locomotion:

PLANTIGRADE: “sole walking”–animals walk by “planting” the full soles of their feet on the ground

DIGITIGRADE: “finger/toe walking”–animals walk with all or most of the length of their toes (“digits”), but not the full soles of their feet

UNGULIGRADE: “hoof walking”–animals walk on only their nails, usually hooves (as in “ungulates”)

Just when I think birds are definitely the strangest group of vertebrates, mammals come back in with baleen.

Baleen whales (or Mysticeti whales) use a system of filter feeding, where they open their mouths to bring in ocean water filled with krill. A whale will then close its mouth partially, and let the water filter through these special baleen plates, catching all of the tasty krill before they can escape! Yes, this is what’s happening in Finding Nemo, and yes, I would love to see what it looks like from inside a whale’s mouth.

This baleen plate is from a fairly small species of whale, as the plate can be taller than a human adult on the bigger species.

Photo credit: Kaitie Janecke Soltesz

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SIZING ALASKA’S MASKED SHREWS - Lathrop High School Senior Kelly May is headed to the National Junior Science & Humanities Symposium in Ohio this month with a research project refuting an earlier study on the effects of climate change on Alaska’s shrews. For this year’s Alaska Statewide High School Science Symposium (ASHSSS), May repeated a study published in 2005 using masked shrew specimens housed at the University of Alaska Museum of the North.

The original study, which concluded that shrews in Alaska are getting larger, was based entirely on data downloaded from the museum’s online database. The authors were not able to inspect each specimen. May believed that not accounting for age in the original research may have biased the results, so he tracked down each of the 650 specimens used in the original study.

Each shrew species has a unique tooth pattern. Since Alaska’s shrews can be difficult to identify, May first confirmed the specimens were the correct species (Sorex cinereus). Determining the age involved looking at the degree of wear on their teeth. Shrews do not hibernate and are active year round but they rarely live more than 15 months. Adults that survive a winter show significant tooth wear, while shrews born in the spring do not.

May learned that young shrews are significantly smaller than overwintered adults and that overwintered females are bigger than overwintered males. In contrast to previously published claims, this means that age and sex both need to be accounted for in studies of body size in shrews, according to the museum’s curator of mammals, Link Olson.

By analyzing juvenile and adult specimens separately and accounting for sex, May found that individual shrews are actually getting smaller but that more are surviving the winter, meaning that the proportion of (larger-bodied) adults in a given population is increasing. So although the two studies reached seemingly similar conclusions, May’s results shed new light on the underlying mechanism:  shrews aren’t growing to a larger body size, they’re just surviving winters better.

In June, May will travel to Philadelphia to present his research at the annual meeting of the American Society of Mammalogists. May plans to attend UAF in the fall.

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Scales, Feathers and Hair Have a Common Ancestor

by NICHOLAS ST. FLEUR

Reptiles have scales. Birds have feathers. Mammals have hair.
How did we get them?

For a long time scientists thought the spikes, plumage and fur characteristic of these groups originated independently of each other. But a study published Friday suggests that they all evolved from a common ancestor some 320 million years ago.

This ancient reptilian creature — which gave rise to dinosaurs, birds and mammals — is thought to have been covered in scale-like structures. What that creature looked like is not exactly known, but the scales on its skin developed from structures called placodes — tiny bumps of thick tissue found on the surface of developing embryos.

Scientists had previously found placodes on the embryos of birds and mammals, where they develop into feathers and hairs, but had never found the spots on a reptilian embryo before. The apparent lack of placodes in present-day reptiles fueled controversy about how these features first formed…

(read more: NY Times)

photographs by Nicolas Di-Poï & Michel C. Milinkovitch

Yesterday was an historic day for the bison.  President Obama signed a law making the bison the country’s first national mammal. Read a story from the New York Times.

Bison once numbered in the tens of millions in North America but, slaughtered for their meat and hides, the population was down to about 1,000 animals by the 1880s. Today, these animals thrive in part due to President Theodore Roosevelt’s efforts. As president, Roosevelt, who had witnessed the bison decline firsthand while living as a rancher in what is now North Dakota, created two big game preserves to save the buffalo from extinction: Montana’s National Bison Range and Oklahoma’s Wichita Game Preserve, where, in 1907, 15 bison bred at New York’s Bronx Zoo were released with a view to eventually repopulating the prairie. This and subsequent efforts brought the bison back from the brink of extinction.

Learn more about bison in this video:

Image: Bison diorama, AMNH/D.Finnin

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Tigers at play (thejunglenook, 6.21.14, Smithsonian National Zoo)
Damai (Mom) and cubs, Bandar and Sukacita, play with their heavy duty safari ball in the moat at the National Zoo. 

Unlike most cats, Sumatran Tigers (Panthera tigris sumatrae) have partially webbed feet and are pretty adept swimmers!

I’m not sure which is the more remarkable specimen in this drawer. On the one hand, you have a very lightly-colored bear pelt that appears to be some sort of unusual Brown Bear (Ursus arctos). This light-tan face coloration mixed with medium brown body and limb fur is not very common, so we are lucky to have such a rare specimen. On the other hand, this drawer also contains Pangolins (family Manidae), every species of which currently faces serous threats due to hunting, trafficking, and habitat loss. This drawer truly holds mammal division treasures!

Photo credit: Ash Boudrie

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Hibernation helps animals like bears, bats, and even frogs survive during lean times. But resting for months at a time also leaves them vulnerable.

For famous hibernators like black bears, predators such as mountain lions can present a threat during their winter rests. A more common one, though, is humans—not because they will attack a bear, but because they can wake it up.

Whether it’s a neighbor’s car alarm or the family dog needing an early walk, no one likes being pulled out of bed earlier than planned. For hibernating animals, an early wake-up call isn’t just an inconvenience—it can be downright lethal. Waking up from hibernation requires a lot of energy, depleting reserves that are key to surviving the winter.

It’s not just bears that are in danger if they wake up from hibernation at the wrong time. In colder areas of North America, many bats species sleep through winters in caves, mines, and other large roosts, known as hibernacula.

In recent years, these populations have been devastated by a disease known as white-nose syndrome, which is caused by the fungus Pseudogymnoascus destructans. The fungus itself isn’t deadly to bats, though.

“What kills the bat is that the fungus makes them wake up, which is very costly,” says Nancy Simmons, curator-in-charge in the Museum’s Department of Mammalogy whose research specialty is bats. “If they wake up too many times, it burns up all the fat they had stored for the winter.”

A version of this story originally appeared in the winter 2017 issue of Rotunda, the Member magazine.

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Neil deGrasse Tyson and panelists discuss de-extinction in the 2017 Isaac Asimov Memorial Debate at the American Museum of Natural History. Biologists today have the knowledge, the tools, and the ability to influence the evolution of life on Earth. Do we have an obligation to bring back species that human activities may have rendered extinct? Does the technology exist to do so? Join Tyson and the panel for a lively debate about the merits and shortcomings of this provocative idea.

2017 Asimov Debate panelists are:

George Church
Professor of Health Sciences and Technology, Harvard University and MIT

Hank Greely
Director of the Center for Law and the Biosciences, Stanford University

Gregory Kaebnick
Scholar, The Hastings Center; Editor, Hastings Center Report

Ross MacPhee
Curator, Department of Mammalogy, Division of Vertebrate Zoology; Professor, Richard Gilder Graduate School

Beth Shapiro
Professor of Ecology and Evolutionary Biology, University of California, Santa Cruz