mammalogy

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”)

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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!

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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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

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Red and White Giant Flying Squirrel | ©Dan Doucette

Petaurista alborufus (Sciuridae) is the largest species of giant squirrel (over 1m from head to tail) and has piercing blue eyes. This species inhabits dense montane forest, limestone cliffs and conifer forests, and it is only found in China.

The specimen shown was photographed in the Foping Nature Reserve, situated in the Qinling Mountains, in Shaanxi Province, China.

Want to see the incredible flight of this squirrel? watch this video. Worth it!

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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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See how she is pregnant.” <– my favorite translated quote

These were the two species caught up in the mist nets the evening Tom and I went out with mammalogist Mario Escobeda to survey for bats during the Tapiche-Blanco Rapid Inventory expedition in Peru. As I mentioned in an earlier post about camera traps, mammalogists have a somewhat tricky time getting an idea of the diversity of an area simply because mammals can be difficult to track. Where a tree leaves (leafs?) clues in the form of fruits and flowers, it can be more of a challenge to get a positive identification for the furry critters in an area. 

Knowing the typical diets of these two bat species - the lesser spear-nosed bat (Phyllostomus elongatus)an insectivore, and Seba’s short-tailed bat (Carollia perspicillata), a fruit-eating seed disperser - can begin to create valuable connections between the animals and their environment, adding more pieces into the puzzle of an ecosystem.

For more on the Rapid Inventory, check out their website
Click here to see all RI tagged posts from The Brain Scoop - and check out the latest episode to see these bats in action!

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Red And White Giant Flying Squirrel - Petaurista alborufus lena 

It is clear that I can not hide my love for flying squirrels. This is the Taiwanese subspecies Petaurista alborufus lena (Rodentia - Sciuridae), which appears to be genetically different from mainland forms in China.

This species has low fecundity, with litter sizes of 1-2. They feed on acorns, other nuts, fruits and leafy vegetation, as well as insects, larvae and perhaps bird eggs.

References: [1] - [2]

Photo credit: ©Georgia Ding | [Top: Da Syue Shan National Forest Recreation Area, Taiwan, 2010] - [Bottom: Snowy Mountains, Yunlin, Taiwan, 2011]

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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

New Research: Analysis of Oldest-known Plant-visiting Bat Suggests It Was Omnivorous

A team of evolutionary biologists from the American Museum of Natural History, Stony Brook University, and the City College of New York has discovered that the oldest known nectar-drinking bat, Palynephyllum antimaster, was probably omnivorous.

Their findings, published in the journal Biology Letters, are based on a new method that allows scientists to estimate skull length, and thus body size, bite force, and diet, from a single fossil molar. The study is the first to provide fossil data showing that the evolution of highly specialized nectar feeding in bats required an omnivorous transition.

“Oftentimes, all we have to work with in the fossil record are one or two teeth, which can severely limit our knowledge about the behavior of an animal,” said paper author Nancy Simmons, curator in the Museum’s Department of Mammalogy. “But the models presented in this paper show how a single tooth can give us enough information to infer many aspects of what an extinct species was like, including what it ate when it was alive.”

Palynephyllum is represented by two molars, dating from the Miocene epoch and found in La Venta, Colombia, which was home to the most diverse vertebrate fossil fauna known from the mid-Miocene. Twelve million years ago, when Palynephyllum lived, this area of South America was teeming with biodiversity, including several types of bats.

Feeding exclusively on nectar, which is basically sugar water, is very physiologically demanding and requires special metabolic adaptations.The molars analyzed in the paper are narrow, and their cusps are reduced and flattened, as they are in nectar-drinking relatives of the fossil living today.

“A longstanding hypothesis holds that species shift to nectar feeding gradually, by first eating a mix of insects and nectar, but this has not been tested with fossils,” said Liliana Dávalos, a professor in the Department of Ecology and Evolution at Stony Brook University and corresponding investigator on the new paper. “Our analyses show that Palynephyllum could not have fed exclusively on nectar, and it likely supplemented its diet with protein-rich insects, which supports this hypothesis.”

Based on their model, which was built by measuring the teeth and skulls of living nectar-feeding bats, the researchers estimated the skull length of the extinct species. They then used the skull length, which relates to key biological traits such as bite force and body size, to infer the diet of the bat.

This post was originally published on the Museum blog

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The Brain Scoop:
Into the Bat Caves of Kenya: Part II 

As we start diving into our footage from Peru, we’ve got the second part of our Kenya bat footage up for your viewing pleasure! This is where it starts to get really grimy. I’ll never forget the sensation of approaching the mouth of a cave that smells heavily of guano, and such promise. 

Watch Part I here! 

Red Ruffed Lemur - Varecia rubra

This is a Red Ruffed Lemur, Varecia rubra (Primates - Lemuridae), a Critically Endangered species with a range restricted to the remaining primary forests of the Masoala Peninsula and the region immediately north of the Bay of Antongil in northeastern Madagascar.

Varecia rubra gets its common name from a ruff of rust red hair that flanks its black face like sideburns. The black face matches the black hands, feet, belly, and tail. Most of the body is covered by a soft, thick, rust red coat, except for a patch of white fur at the back of the head.

In just six years this species went from Endangered (1990) to Critically Endangered (1996).

References: [1] - [2]

Photo credit: ©Alan Shapiro | Locality: not indicated (2015)

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Photos of the fabulous prehistoric horse diorama at The Horse exhibit, currently at The Natural History Museum of Utah.  The travelling exhibit was created by the American Museum of Natural History.