We talked a little bit last week about some truly strange animals, and I thought this week we’d continue our little sojourn into the animal kingdom. Our first animal is no longer with us, but he was a bizarre little thing.
DINOSAURS COME IN SMALL PACKAGES TOO
We’re all familiar with T-rex and Stegasaurus and Apatosaurus and all the other enormous dinosaurs but big isn’t the only size for dinosaurs. Canadian researchers have recently uncovered a chicken-sized dinosaur that ran on two legs and scoured the forest floor for termites. They are the smallest dinosaurs ever discovered in North America.
They have long, slender legs, stumpy arms with huge claws and jaws like tweezers. One of the paleontologists who discovered them says they look like an animal created by Dr. Seuss.
Scientists named them Albertonykus borealis because they were found in the northern province of Alberta. The small dinosaurs apparently were termite eaters and used their powerful forelimbs to tear into infested logs. Their fossils were dated at 70 million years old.
Albertonykus has relatives in Asia and the recently discovered fossils are evidence of the oldest and most complete dinosaur of its kind known from North America. The researchers say that the skeleton provides evidence that these dinosaurs migrated to Asia through North America.
Migrating chicken-sized dinos, eh? Our next story also examines animal migration but this one has some scary overtones.
CLIMBING THE MOUNTAIN
A study done in Yosemite National Park and recently published in the journal Science has discovered something troubling about the small mammal populations in the park. They’ve done surveys of shrews, mice and ground squirrels and compared their findings with data from 90 years ago and discovered that many of them are headed for higher ground. The apparent reason? Global warming.
The original purpose of the research was not to study climate change, but when they discovered that virtually every studied mammal was found at higher elevations than those reported in the last full scale survey in Yosemite in 1918.
The central Sierra Nevada mountains have seen a general warming, shown not only by a 3 degree Celsius increase in nighttime low temperatures (about 5 degrees F.), but also the receding of glaciers – Lyell Glacier is half the size it was 100 years ago – and the increase in precipitation as rain instead of snow.
While the population movements have not altered biodiversity in the park, UC Berkeley biologists say rapid changes in less than a century could be a problem. Although half the species shifted their ranges, the other half did not, which means communities have been altered and the species interacting with one another have changed.
Although changes in community composition are common, what makes this one different is that it has happened in our lifetimes. It’s the speed of change that has the scientists worried. If the movements are slow, the ecosystem has time to adapt to the changes, but we have no idea of the potential consequences of such rapid change.
The foundation for the current study is a landmark survey of Sierra Nevada birds, mammals, reptiles and amphibians initiated early last century by Joseph Grinnell, founding director of the museum and a zoology professor at UC Berkeley. With a large number of colleagues and students, Grinnell traipsed through the Sierra Nevada – from the Modoc Plateau in the north to the San Jacinto range in the south – collecting specimens and recording for posterity the variety of life then under threat from gold mining and overgrazing.
The current researchers proposed resurveying all the sites visited by Grinnell and his colleagues, starting with the Yosemite transect originally surveyed from 1914 to 1920, which stretched from the San Joaquin Valley through the park and over the Sierra crest to Mono Lake. With funding from the National Science Foundation, the Yosemite Foundation and the National Park Service, the Grinnell Resurvey Project commenced in 2003. This information is the first result of the survey and it appeared on the 100th anniversary of the founding of the museum in 1908.
The researchers found that, of the 28 small mammals observed in the transect, half had expanded their range upward by more than 500 meters, or 1,600 feet. While low-elevation species such as the California vole and the California pocket mouse increased their range by moving upslope, high-elevation species such as the bushy-tailed woodrat and Allen’s chipmunk generally decreased their ranges. Short-lived, fast-breeding species were more likely to expand their ranges than were their long-lived, less fecund relatives.
Upward movement has caused the range of the alpine chipmunk to shrink and possibly put the chipmunk, one of California’s few endemic mammals, at risk of extinction. Although 90 years ago the chipmunk was common on granite slabs in lodgepole pine forests below 7,800 feet, the researchers were unable to find any below 9,600 to 9,800 feet, an upward movement of 2,000 feet.
Similarly, on the eastern slopes of the Sierra, the one-ounce pinyon mouse has moved entirely out of the pinyon pine/juniper belt into a very different habitat, the mountain forest, which is dominated by whitebark pine.
While higher elevation shifts were driven primarily by climate, the researchers noted that lower-elevation changes probably had something to do with land use changes. A third mammal impacted significantly in the past 90 years is the Trowbridge shrew, which used to be the only shrew in Yosemite Valley. Today, with the departure of Indians who regularly burned the valley, the valley is wetter, and the Trowbridge shrew has been totally replaced by the montane shrew, which moved downslope to recolonize the valley.
Animals on the move because of climate change. And yet there are still people who say that global warming is a crock. I hope they can swim!! (or perhaps climb!)
A pika seen at Lembert Dome in Yosemite National Park. (Credit: Emily Rubidge photo)
The pika in the picture is an adorable little fellow, but there are animals out there that are well, Furbies. Do you remember Furbies? They were those adorable little stuffed robots that were all the rage a few years ago. Well, newly discovered primates in Indonesia look like Furbies come to life.
FURBY, WHERE ART THOU?
A team led by a Texas A&M University anthropologist has discovered a group of primates not seen alive in 85 years. The pygmy tarsiers, furry Furby-like creatures about the size of a small mouse and weighing less than two ounces, have not been observed since they were last collected for a museum in 1921. Several scientists believed they were extinct until two Indonesian scientists trapping rats in the highlands of Sulawesi accidentally trapped and killed a pygmy tarsier in 2000.
The researchers trapped three of the nocturnal creatures in Indonesia in late August last year. Pygmy tarsiers have fingers with claws instead of nails, which distinguishes them from nearly all other primates that have nails and not claws. The claws may be an adaptation to the mossy environment in which the tarsiers live.
Over a two-month period, two males and one female were trapped on Mt. Rore Katimbo in Lore Lindu National Park in Central Sulawesi, Indonesia. The scientists used almost 300 mist nets to capture the creatures, then fitted them with radio collars so their movements could be tracked.
The tarsiers live in mountainous terrain at
heights of 7,000 to 8,000 feet. This makes them difficult to get to and their habitat plus the fact that they’re nocturnal has probably saved them from the extinction that everyone believed had overtaken them. The researchers are hoping to convince the Indonesian government to lay on extra protection for these bizarre creatures.
A pygmy tarsier being held by a researcher. The primate weighs less than two ounces and is about the size of a mouse. (Credit: Image courtesy of Texas A&M University)
Chicken-sized dinosaurs, traveling mammals and a living Furby. Welcome to the wonderful world of Earth’s animals! Cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about living Furbies and many other topics. Enjoy!