Primates
milhayser | May 24, 2012
On the Weizmann Wave, researchers have made a discovery surrounding exons—"bits of genetic code that are snipped out of the sequence and spliced together to make the protein instruction list." When a cell needs to make a protein, it pulls exons out of pre-messenger RNA and stitches them together to form messenger RNA. Alternating sequences called introns are left out. By tracking the unused introns, researchers observed that "in some cases, pre-mRNA production shot straight up - to ten times or more than that of the mRNA that followed." They call this "production overshoot," for when "the…
laelaps | July 5, 2010
A collared brown lemur (Eulemur collaris) baby, photographed at the Bronx Zoo.
laelaps | June 23, 2010
The skeletons of Lucy (left) and Kadanuumuu (right). Both belong to the early human species Australopithecus afarensis. (Images not to scale.)
I never fully appreciated how small Lucy was until I saw her bones for myself. Photographs and restorations of her and her kin within the species Australopithecus afarensis had never really given me a proper sense of scale, and when I looked over her incomplete skeleton - formally known as specimen A.L. 288-1 - I was struck by her diminutive proportions. In life she would have only been about three and a half feet tall. Her physical stature seemed…
laelaps | June 22, 2010
Three-dimensional models of hominoid skulls used in the study - (a) Hylobates lar; (b) Pongo pygmaeus; (c) Pan troglodytes; (d) Gorilla gorilla; (e) Australopithecus africanus; (f ) Paranthropus boisei; (g) Homo sapiens. They have been scaled to the same surface area, and the colors denote areas of stress (blue = minimal stress, pink = high stress). From Wroe et al, 2010.
It is all too easy to think of human evolution in linear terms. From our 21st century vantage point we can look back through Deep Time for the first glimmerings of the traits we see in ourselves, and despite what we have…
laelaps | June 10, 2010
"Dinah", a young female gorilla kept at the Bronx Zoo in 1914. From the Zoological Society Bulletin.
Frustrated by the failure of gorillas to thrive in captivity, in 1914 the Bronx Zoo's director William Hornaday lamented "There is not the slightest reason to hope that an adult gorilla, either male or female, ever will be seen living in a zoological park or garden." Whereas wild adult gorillas were "savage" and "implacable" beasts which could not be captured (a photo of a sculpture included in Hornaday's article depicts a gorilla strangling one man, brandishing another about with its other…
laelaps | June 7, 2010In the part of suburban New Jersey I grew up in, almost every other school took the cougar for its sports team mascot. There were the Carl H. Kumpf Middle School Cougars, the Cranford High School Cougars, and the Kean University Cougars, among others. Nevermind that cougars were extirpated from the state long ago - they were a top choice as symbols of the agility, cunning, and ferocity sports teams like to believe they channel. The use of such totems extends beyond sports. Exxon tells us we can "put a tiger in the tank" by using their fuel, and many people adorn themselves with clothing or…
laelaps | May 31, 2010
The skull of Paranthropus boisei ("Zinj," "Dear Boy," "Nutcracker Man," etc.).
Louis Leakey had a problem.
During the summer of 1959 he and his wife Mary recovered the skull fragments of an early human scattered about the fossil deposits of Olduvai Gorge in Tanzania. The skull had been deposited among the shattered bones of fossil mammals and a collection stone tools, and this led Louis to conclude that it was one of our early ancestors. Only an ancestor of Homo sapiens could be a toolmaker, Louis thought, but the skull looked nothing like that of our species.
When Mary fit all the pieces…
laelaps | May 15, 2010
A baby Coquerel's sifaka (Propithecus coquereli), photographed at the Bronx Zoo.
laelaps | May 12, 2010
In the Fayum desert of northern Egypt, not too far from the banks of the Nile, the vestiges of ancient forests are preserved in the sand-covered strata. The fossils are ghosts of a vanished oasis in which prehistoric cousins of modern elephants wallowed in lush wetlands and a host of ancient primates scrambled through the trees, and despite being known as one of the world's best fossil sites for over a century paleontologists are continuing to discovery new species from the desert rock. The trouble is that not all these new species are easily classified.
Approximately 37 million years ago,…
laelaps | April 29, 2010
Utah may seem like an odd place to search for primates, but you can find them if you know where to look. Although scrubby and arid today, between 46-42 million years ago what is now the northeastern part of the state was a lush forest which was home to a variety of peculiar fossil primates. Called omomyids, these relatives of living tarsiers are primarily known from teeth and associated bits and pieces of bone, but newly discovered postcranial remains may provide paleontologists with a better idea of how some of these ancient primates moved.
For most of their early evolution omomyids were…
laelaps | April 8, 2010
A diagram of how the skeletons of Australopithecus sediba came to be preserved in the Malapa cave deposit. From Dirks et al, 2010.
A little less than two million years ago, in what is now South Africa, a torrential downpour washed the bodies of two humans into the deep recesses of a cave. Just how their remains came to be in the cave in the first place is a mystery. Perhaps they fell in through the gaping hole in the cave roof just as hyenas, saber-toothed cats, horses, and other animals had, but, however the humans entered the cave, their bones ultimately came to rest in a natural bowl…
laelaps | April 7, 2010
A leopard (Panthera pardus). Image from Wikipedia.
When a leopard eats a baboon, what is left behind? This question is not only relevant to primatologists and zoologists. Even though instances of predation on humans is relatively rare, big cats still kill and consume people, and when they do they can virtually obliterate a body. Yet, just like a human criminal, the dining habits of big cats leave tell-tale clues, and in 2004 researchers Travis Pickering and Kristian Carlson fed two captive leopards eight complete baboon carcasses each in order catalog the most useful ways to identify the…