Male and female dinosaurs may have shared the responsibility of
incubating their offspring, but how to determine which parent was
involved remains a mystery, according to a new study that re-examines
the idea that the brooding behavior of modern birds may predict similar
behavior in their dinosaur ancestors.
Modern birds are thought to have evolved from theropods, a group of
carnivorous dinosaurs that include such recognizable predators as the Velociraptor and Tyrannosaurus rex.
In research published in the journal Science in 2009, scientists
examined the way existing birds incubate their eggs, claiming that only
male theropods took part in incubation. But the study, which compared
the size of male and female birds with the size and number of eggs that
were laid, omits some important factors, said Geoff Birchard, a
professor in the department of environmental science and policy at
George Mason University in Fairfax, Va., and co-author of the new study.
[Image Gallery: Dinosaur Daycare]
"They looked at the number of eggs and how big they were, and said they
could figure out whether mommy incubated, daddy incubated, or both
did," Birchard told LiveScience. "The problem is, the biology behind it
is a little bit off."
Birchard and his colleagues repeated the 2009 study using more data
from living bird species. They determined that comparing the size of the
birds with the clutch size — which is determined by multiplying the
number of eggs laid in a nest by the volume or mass of the eggs — could
not effectively determine whether it was the male or female guarding the
eggs.
"Our analysis of the relationship between female body mass and clutch
mass was interesting in its own right, but also showed that it was not
possible to conclude anything about incubation in extinct distant relatives of the birds," study co-author Charles Deeming, a researcher at the University of Lincoln in the United Kingdom, said in a statement.
Part of the problem is that birds do not all exhibit the same brooding behavior.
"There's a huge amount of variation with birds," Birchard said. "With
certain bird types, two parents are always involved, but with some
bigger birds, only the daddy is incubating the eggs. With dinosaurs,
overall, there's a huge amount of variety, too."
And whether the actions of modern birds can be used to predict the behavior of dinosaurs is also a source of debate.
"There are great differences of opinion about it," Birchard said.
"There's a long time gap between dinosaurs and the origin of birds, so
it's an awful long time for us to say what's being done with birds was
also being done with dinosaurs. We use this kind of inference sometimes,
but birds are also a very unique group."
The findings of the new study were published online Tuesday (May 14) in the journal Biology Letters.
Darla
Zelenitsky from the University of Calgary collaborated with David
Varricchio at Montana State University to closely examined the shells of
fossil eggs from a small meat-eating dinosaur called Troodon.
Published: Thursday, April 18, 2013
Jay Im (University of Calgary).
A small, bird-like North American dinosaur incubated its
eggs in a similar way to brooding birds -- bolstering the evolutionary
link between birds and dinosaurs, researchers at the University of
Calgary and Montana State University study
have found. Among the many mysteries paleontologists have tried to
uncover is how dinosaurs hatched their young. Was it in eggs completely
buried in nest materials, like crocodiles? Or was it in eggs in open or
non-covered nests, like brooding birds?
Using egg clutches found in Alberta and Montana, researchers Darla
Zelenitsky at the University of Calgary and David Varricchio at Montana State University closely examined the shells of fossil eggs from a small meat-eating dinosaur called Troodon.
In a finding published in the spring issue of Paleobiology,
they concluded that this specific dinosaur species, which was known to
lay its eggs almost vertically, would have only buried the egg bottoms
in mud. "Based on our calculations, the eggshells of Troodon were
very similar to those of brooding birds, which tells us that this
dinosaur did not completely bury its eggs in nesting materials like
crocodiles do," says study co-author Zelenitsky, assistant professor of
geoscience. "Both the eggs and the surrounding sediments indicate only partial
burial; thus an adult would have directly contacted the exposed parts of
the eggs during incubation," says lead author Varricchio, associate
professor of paleontology.
Varricchio says while the nesting style for Troodon is
unusual, "there are similarities with a peculiar nester among birds
called the Egyptian Plover that broods its eggs while they're partially
buried in sandy substrate of the nest."
Paleontologists have always struggled to answer the question of how
dinosaurs incubated their eggs, because of the scarcity of evidence for
incubation behaviours. As dinosaurs' closest living relatives, crocodiles and birds offer some insights. Scientists know that crocodiles and birds that completely bury their
eggs for hatching have eggs with many pores or holes in the eggshell, to
allow for respiration. This is unlike brooding birds which don't bury their eggs; consequently, their eggs have far fewer pores.
The researchers counted and measured the pores in the shells of Troodon
eggs to assess how water vapour would have been conducted through the
shell compared with eggs from contemporary crocodiles, mound-nesting
birds and brooding birds. They are optimistic their methods can be applied to other dinosaur
species' fossil eggs to show how they may have been incubated. "For now, this particular study helps substantiate that some
bird-like nesting behaviors evolved in meat-eating dinosaurs prior to
the origin of birds. It also adds to the growing body of evidence that
shows a close evolutionary relationship between birds and dinosaurs," Zelenitsky says.
Dinosaur embryos twitched in their eggs like those of modern birds
A collection of embryos fossilised at various ages in different nests reveals how dinosaurs developed in the egg
Alok Jha, science correspondent
The Guardian,
A Lufengosaurus dinosaur embryo inside its egg. Illustration: D. Mazierski
Dinosaur embryos moved around inside their eggs and grew in much
the same way as those of modern animals such as birds, say scientists
who have examined more than 200 fossilised bones from 190m-year-old
embryos found in China.
The bones came from the genus known as Lufengosaurus,
a long-necked dinosaur that could grow up to eight metres long, and
were found among fragments of egg shells at a site near the city of
Lufeng in Yunnan, south west China. They are the oldest dinosaur embryos
ever found and seem to have come from several nests and from eggs at
various stages of development. "Most of the time you get single
glimpses of embryonic life in a dinosaur because they are preserved as a
nest and all the eggs are in the same developmental stage," said Robert
Reisz, a palaeontologist at the University
of Toronto Mississauga, who led the team that analysed the bones. "Here
we have a growth series of embryos, which allowed us to track how these
animals grew."
The team's results are published in the journal Nature.
Reisz's team focused their analysis on the largest bone, the femur.
They found that, inside the eggs, these bones seemed to be growing very
quickly, implying that their incubation period might have been
relatively short.
Inside the bones is a honeycomb structure of
"primary spaces". The larger these are, said Reisz, the faster the
embryo would have grown. In addition, the scientists found that the
bones were shaped inside the eggs, as they grew, as attached muscles pulled on them. "This suggests that dinosaurs,
like modern birds, moved around inside their eggs," said Reisz. "It
represents the first evidence of such movement in a dinosaur.
Adélie penguin. The population size of an Adélie penguin colony on
Antarctica’s Beaufort Island increased 84 percent as the ice fields
retreated between 1958-2010, with the biggest change in the last three
decades. (Credit: University of Minnesota)
Apr. 3, 2013 — Adélie
penguins may actually benefit from warmer global temperatures, the
opposite of other polar species, according to a breakthrough study by an
international team led by University of Minnesota Polar Geospatial
Center researchers. The study provides key information affirming
hypothetical projections about the continuing impact of environmental
change.
Researchers from the United States and New Zealand used a mix of old
and new technology studying a combination of aerial photography
beginning in 1958 and modern satellite imagery from the 2000s. They
found that the population size of an Adélie penguin colony on
Antarctica's Beaufort Island near the southern Ross Sea increased 84
percent (from 35,000 breeding pairs to 64,000 breeding pairs) as the ice
fields retreated between 1958-2010, with the biggest change in the last
three decades. The average summer temperature in that area increased
about a half a degree Celsius per decade since the mid-1980s.
The first-of-its-kind study was published today in PLOS ONE,
a leading peer-reviewed scientific journal. The research affirms models
published in 2010 projecting how south polar penguins will respond to
changed habitat as Earth's atmosphere reaches 2 degrees Celsius above
pre-industrial levels, a point that is rapidly approaching.
The study showed that available habitat for Adélie penguins on the
main portion of the Beaufort colony, on the south coast, increased 71
percent since 1958, with a 20 percent increase from 1983-2010. The
extent of the snow and ice field to the north of the main colony did not
change from 1958-1983, but then retreated 543 meters from 1983-2010.
In addition to the overall population growth, researchers saw an
increase in population density within the colony as it filled in what
used to be unsuitable habitat covered in snow and ice. They also found
that the emigration rates of birds banded as chicks on Beaufort Island
to colonies on nearby Ross Island decreased after 2005 as available
habitat on Beaufort increased, leading to altered dynamics of the
population studied. "This research raises new questions about how Antarctic species are
impacted by a changing environment," said Michelle LaRue, the paper's
co-author and research fellow at the Polar Geospatial Center in the
University of Minnesota's College of Science and Engineering. "This
paper encourages all of us to take a second look at what we're seeing
and find out if this type of habitat expansion is happening elsewhere to
other populations of Adélie penguins or other species."
Penguin expert and study co-author David Ainley, a lead author of an
earlier study, agreed that this study gives researchers important new
information. "We learned in previous research from 2001-2005 that it is a myth
that penguins never move to a new colony in large numbers. When
conditions are tough, they do," said Ainley, a senior marine wildlife
ecologist with H.T. Harvey and Associates, an environmental consulting
company in California. "This study at Beaufort and Ross Islands provides
empirical evidence about how this penguin attribute will contribute to
their response to climate change."
Adélie penguins are common along the southern Antarctic coast. They
are smaller than their Emperor penguin counterparts standing about 46 to
75 cm (18 to 30 inches) when upright and weighing about 4.5-5.4 kg
(10-12 pounds). The Adélie penguin lives only where there is sea ice but
needs the ice-free land to breed. Breeding pairs produce on average one
chick per year and return to the same area to breed if conditions
haven't changed.
To determine changes in available nesting habitat in this study,
researchers gathered aerial photos during the penguin incubation period
in 1958, 1983 and 1993 and high-resolution satellite images from 2005
and 2010. Researchers overlaid the images exactly, lining up rocks and
other geographical landmarks. They studied guano (penguin feces and
urine) stains to determine the available habitat.
In the future, researchers plan to use additional satellite imagery
to look at other Adélie penguin populations to help understand the
dynamics and environmental factors that influence regional populations. "This study brought together researchers from different academic
disciplines who all contributed their expertise," LaRue said. "We had
people who study climate change, spatial analysis, and wildlife
population dynamics. This is how good science leads to results."
In addition to LaRue and Ainley, other researchers involved in the
study included Matt Swanson, a graduate student researcher at the
University of Minnesota Polar Geospatial Center; Katie M. Dugger from
Oregon State University; Phil O'B. Lyver from Landcare Research in New
Zealand; Kerry Barton from Bartonk Solutions in New Zealand; and Grant
Ballard from PRBO Conservation Science in California.
The study was primarily funded by the National Science Foundation (NSF).
Story Source:
The above story is reprinted from materials provided by University of Minnesota. Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Michelle A. LaRue, David G. Ainley, Matt Swanson, Katie M. Dugger, Phil O′B. Lyver, Kerry Barton, Grant Ballard. Climate Change Winners: Receding Ice Fields Facilitate Colony Expansion and Altered Dynamics in an Adélie Penguin Metapopulation. PLoS ONE, 2013; 8 (4): e60568 DOI: 10.1371/journal.pone.0060568
Only one penguin species lives in Africa today -- the endangered
black-footed penguin, or Spheniscus demersus. But newly found fossils
confirm that as many as four penguin species coexisted on the continent
in the past. (Credit: Photo by Daniel Thomas)
Mar. 26, 2013 — Africa isn't
the kind of place you might expect to find penguins. But one species
lives along Africa's southern coast today, and newly found fossils
confirm that as many as four penguin species coexisted on the continent
in the past. Exactly why African penguin diversity plummeted to the one
species that lives there today is still a mystery, but changing sea
levels may be to blame, the researchers say.
The fossil findings, described in the March 26 issue of the Zoological Journal of the Linnean Society,
represent the oldest evidence of these iconic tuxedo-clad seabirds in
Africa, predating previously described fossils by 5 to 7 million years.
Co-authors Daniel Thomas of the National Museum of Natural History
and Dan Ksepka of the National Evolutionary Synthesis Center happened
upon the 10-12 million year old specimens in late 2010, while sifting
through rock and sediment excavated from an industrial steel plant near
Cape Town, South Africa.
Jumbled together with shark teeth and other fossils were 17 bone
fragments that the researchers recognized as pieces of backbones,
breastbones, wings and legs from several extinct species of penguins.
Based on their bones, these species spanned nearly the full size
spectrum for penguins living today, ranging from a runty pint-sized
penguin that stood just about a foot tall (0.3 m), to a towering species
closer to three feet (0.9 m).
Only one penguin species lives in Africa today -- the black-footed penguin, or Spheniscus demersus,
also known as the jackass penguin for its loud donkey-like braying
call. Exactly when penguin diversity in Africa started to plummet, and
why, is still unclear.
Gaps in the fossil record make it difficult to determine whether the
extinctions were sudden or gradual. "[Because we have fossils from only
two time periods,] it's like seeing two frames of a movie," said
co-author Daniel Ksepka. "We have a frame at five million years ago, and
a frame at 10-12 million years ago, but there's missing footage in
between."
Humans probably aren't to blame, the researchers say, because by the
time early modern humans arrived in South Africa, all but one of the
continent's penguins had already died out.
A more likely possibility is that rising and falling sea levels did them in by wiping out safe nesting sites.
Although penguins spend most of their lives swimming in the ocean,
they rely on offshore islands near the coast to build their nests and
raise their young. Land surface reconstructions suggest that five
million years ago -- when at least four penguin species still called
Africa home -- sea level on the South African coast was as much as 90
meters higher than it is today, swamping low-lying areas and turning the
region into a network of islands. More islands meant more beaches where
penguins could breed while staying safe from mainland predators.
But sea levels in the region are lower today. Once-isolated islands
have been reconnected to the continent by newly exposed land bridges,
which may have wiped out beach nesting sites and provided access to
predators.
Although humans didn't do previous penguins in Africa in, we'll play a
key role in shaping the fate of the one species that remains, the
researchers add.
Numbers of black-footed penguins have declined by 80% in the last 50
years, and in 2010 the species was classified as endangered. The drop is
largely due to oil spills and overfishing of sardines and anchovies --
the black-footed penguin's favorite food.
"There's only one species left today, and it's up to us to keep it safe," Thomas said.
Story Source:
The above story is reprinted from materials provided by National Evolutionary Synthesis Center (NESCent), via EurekAlert!, a service of AAAS. Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
Daniel B. Thomas, Daniel T. Ksepka. A history of shifting fortunes for African penguins. Zoological Journal of the Linnean Society, 2013; DOI: 10.1111/zoj.12024
Sunny side up. The follicles (close-up, inset) preserved in the fossilized ovary of this 125-million-year-old bird (main image), provide insights into the reproductive biology of these early birds and into bird evolution.
Credit: Aijuan Shi; Zhonghe Zhou (inset)
The dinosaurs most closely related to today's birds were super egg
producers. Known as maniraptorans, these bipedal creatures had two
functional ovaries
and produced a large number of eggs per clutch. Living species of
birds, on the other hand, have only one functional ovary, typically on
the left side of
the body, and most produce only a few eggs at a time. When and why
did today's flyers ditch a reproductive organ? Newly described fossils
of early birds
may hold the answer.
All the fossils in this study come from rocks laid down as sediments
about 125 million years ago in northeastern China. Despite the poor
bone preservation
in two of the fossils, all include the well-preserved remains of
ovaries and mature or nearly mature follicles, structures within the
ovaries that contain
developing eggs—the first such fossils of early birds known to do
so, says Zhonghe Zhou, a paleontologist with the Institute of Vertebrate
Paleontology
and Paleoanthropology in Beijing. One set of remains represents Jeholornis,
a long-tailed bird about the size of a pigeon.
Neither of the other
fossils is preserved well enough to identify its species, Zhou
notes, but each represents a bird somewhat larger than a sparrow. Each
of the fossils
included only one ovary—which, as in modern birds, appears to be
located on the left side of the body.
Analyses by Zhou and his colleagues showed that the structures
assumed to be follicles weren't seeds, because they weren't located in
parts of the body
where stomach contents would typically be found. The structures also
weren't gastroliths, or stomach stones, because such stones typically
retain their
three-dimensional shape, whereas these structures appeared to have
been soft tissue because they had been somewhat flattened before they
were preserved.
"These are really incredible fossils," says Stephen Brusatte, a
vertebrate paleontologist at the University of Edinburgh in the United
Kingdom who wasn't
involved in the study. Preservation of soft tissues is exceedingly
rare, he notes, but "to have ovarian follicles preserved is just
amazing."
The fossils furnish information about the reproductive habits of
these animals. In one of the birds, some of the bones in the creature's
wing weren't fully
fused, Zhou says. That suggests that the creature wasn't an adult,
hinting that females of its species became sexually mature before they were fully grown, he and his colleagues
report online today in Nature.
One of the fossilized ovaries includes at least 20 mature or
near-mature follicles. That's a sign that unlike modern birds, early
birds probably laid a
large number of relatively small eggs in a single clutch, Brusatte
says. "We don't have any fossil nests of early birds, but this tells us
that the
reproductive biology of early birds was quite different than modern
birds."
Some scientists have assumed that the evolutionary loss of one
functional ovary—a weight-saving change that might have proved
beneficial to flying birds—took place early in avian evolution. Until
the new study, paleontologists hadn't unearthed any evidence for the
notion that early birds, like their
modern-day kin, had only one ovary.
The findings even provide hints about how early birds cared for
their young, says Richard Prum, an evolutionary ornithologist at Yale
University. Previous
analyses of fossil dinosaur nests have suggested that in birds'
closest dinosaur relatives, which laid large clutches of eggs, males sat
on the nests and
presumably cared for the hatchlings. That's also true of some of
today's birds—including ratites, a group that includes ostriches and
emus—which
typically lay eggs in several nests and then leave the childcare to
males. "So, large clutch size in early birds is strong evidence for male
care," Prum
contends.
The new findings "are very exciting," says Frankie Jackson, a
vertebrate paleontologist at Montana State University, Bozeman. Besides
revealing that even
early birds had reproductive biology significantly different from
that of their closest dinosaur kin, they provide a new approach to
estimate the brood
size and the onset of sexual maturity in adults. These reproductive
traits—including the loss of one of the ovaries, which probably would
have rendered
egg-laden females significantly lighter—likely had a substantial
impact on the evolution of flight, she notes. That development may even
have helped
some bird lineages survive the mass extinctions in the wake of an
asteroid impact that claimed the dinosaurs 66 million years ago.
Sapeornis fossils, with long leg feathers. From Zheng et al, 2013. Science/AAAS
Not Exactly Rocket Science:
2 days ago
by Ed Yong
Look at the leg of almost any bird and you’ll see feathers
covering the thigh but scales covering everything from the ‘knee’
downwards. There are a couple of exceptions—some birds of prey look like
they’re wearing baggy trousers and golden eagles have fluffy foot
feathers for insulation. But for the most part, living birds have naked
lower legs.
It wasn’t always this way. We know that birds evolved from small
two-legged, meat-eating dinosaurs that were covered in simple fuzzy
feathers. Those on their arms eventually became longer and flatter,
evolving from hollow tubes into flat asymmetrical vanes. They transformed from “dino-fuzz” into flight feathers, and their arms transformed into wings.
Meanwhile, it’s tempting to think that the feathers on their hind
legs gradually became smaller and gave way to scales. But that’s not how
it happened. For a start, we know that some small dinosaurs had long feathers on their legs
as well as their arms. And now, 11 newly analysed fossils tell us that
some early birds shared the same feature. These specimens suggest that
some of our feathered friends had four wings.
It was an ornithologist called William Beebe
who first suggested that early birds might have passed through a
four-winged gliding stage on their way to evolving true flapping flight.
That was in 1915 and though Beebe’s idea was fanciful, there wasn’t
much strong evidence behind it.
Then, in 2003, the prolific Chinese dinosaur-hunter Xing Xu found an actual four-winged dinosaur. He called it Microraptor gui.
Xu saw the outlines of feathers clearly splaying from the creature’s
legs as well as its arms. These were clearly traces of long, flat and
asymmetric plumes, much like those that keep today’s flying birds aloft.
While it lived, Microraptor probably looked like a starling wearing flares. Xu suggested that itmay have used its leg wings to help it glide, while others later suggested that it could have flown like a biplane.
Xu went on to find other dinosaurs with long leg feathers, such as Anchiornis, Pedopenna and Xiaotingia.
For a time, it looked like these feathers disappeared before true birds
arrived on the scene, but Xu is now back with 11 new fossils that
discount that idea.
Confuciusornis. From Zheng et al, 2013. Science/AAAS
The specimens include species like Sapeornis, Confuciusornis, Cathayornis, and Yanornis.
All of them are early birds, perched on primitive branches of the
group’s family tree. All of them lived in China during the Cretaceous
period. And all of them had four wings, with long feathers on their
legs.
You can see them in the images throughout this post—dark shadows
protruding from the bones of the lower leg. In some of the specimens,
the leg feathers show a stiff, curved central rod (or “rachis”) with
symmetrical vanes sticking out from either side. They protrude from the
bones at right angles and seem to form a large flat surface.
Xu thinks that these feathers might have helped the owners to fly.
They could have produced extra lift or maybe helped the birds to turn
more easily. But other scientists who work on the evolution of flight
are not convinced. “[Xu] has basically just taken a punt that because
the feathers were stiff, they were probably aerodynamic in function,”
says Michael Habib from the University of Southern California. “It is a bit of a weak argument.”
Habib thinks that the long asymmetric leg feathers of Microraptor probably did play
some role in gliding or flying, but the smaller plumes of other
baggy-legged species “might have merely been there because of a
developmental quirk”. If some genes are producing large feathers on the
front limbs, “it might not take much to tweak a set onto the hind limbs
too,” he says.
Kevin Padian
from the University of California, Berkeley agrees. He points out that
no one has actually done any proper tests to show if the leg feathers
were involved in flight. They would certainly have created drag, but
they could only have provided lift if they sat in a flat sheet like the
wings of modern birds. Xu claims that they were, but Padian says that
the feathers could just have been flattened into a plane as they became
fossilised. “It hasn’t been shown that this is really an
aerodynamically competent wing,” he says.
Nonetheless, both Habib and Padian praise Xu’s work. “It’s a great
study because it establishes that leg feathers were widely distributed,”
says Padian. From beginnings as small outgrowths, leg feathers became
dramatically bigger in some of the dinosaur groups on the evolutionary
line leading to birds. They eventually shrank away again before
disappearing entirely and being replaced by scales.
Scenario for the evolution of leg feathers. From Zheng et al, 2013. Science/AAAS
Of course, like any evolutionary story, this one could be falsified
or complicated by the next cool discovery. Xu says that if he discovered
early birds or feathered dinosaurs with extensive scales on their feet,
that would spell trouble for his hypothesis. “But personally, I am
quite confident with our scenario,” he says.
Why did the leg feathers, having first become large, eventually
disappear? Xu thinks that it was because the birds set their two pairs
of limbs towards different ends—the front pair for flying and the hind
pair for walking or running. At the same time, they might have moved
from life in the trees to life on the ground, or near water. Under all
these scenarios, long leg feathers would have just got in the way, and
were soon lost.
Something similar may have happened in other flying animals. For
example, the earliest flying insects tend to have four wings, while some
of the most competent flyers like, well, flies, only have two. The
second pair has evolved into a pair of gyroscopes called halteres. “In
the early evolution of flight, different animal groups always try to use
as much surface as possible,” says Xu. “Once the major flight organ is
well developed, the animal just fires the other organs.”
Xu’s 11 specimens all came from private collectors and had been
housed at the Shandong Tianyu Museum of Nature for roughly a decade. The
museum contains over 2,000 specimens of early birds, many of which
preserve beautiful traces of feathers, skin and more. In fact, the
museum’s treasure trove of riches is so huge that it has turned into a
backlog. There’s simply too much good stuff there to go through. “It
took a while for me to realize how important these specimens are,” says
Xu. “These days, we are working hard to extract new information from
these wonderful specimens and hopefully can produce more interesting
results in future.”
Reference: Zheng, Zhou, Wang, Zhang, Zhang, Wang, Wei, Wang
& Xu. 2013. Hind Wings in Basal Birds and the Evolution of Leg
Feathers. Science http://dx.doi.org/10.1126/science.1228753
Very important information has recently come to my attention. Some penguins are prostitutes.
We all know humans do it. Some people will even show their boobs to a prison guard for a chocolate chip cookie,
but penguins?! Those adorable animals dressed like banquet waiters who
engage in Morgan Freeman-narrated lifelong monogomy? Yes. They're
prostitutes.
It's not exactly new news but an alert reader Jake H.
pointed me towards a 1998 study that somehow didn't make it to my daily
reading habits because it's too amazing. Apparently when the small rocks
they use to make nests get scarce, some penguins will exchange sexual
favors for them. Not only do they prostitute themselves, they do it for
pebbles!
According to this excellent Wikipedia article,
prostitution has also been observed in chimpanzees, Capuchin monkeys,
and the crab-eating macaque. That's not super surprising: chimpanzees
and Capuchins are gross. And of course something called a "crab-eating
macaque" would sell its body (am I right ladies?). But penguins?
PENGUINS? I feel let down.
Read some more about the behavior (and make sure to hear Morgan Freeman's voice in your head):
The female penguins observed under the study were coupled
with males. The females will go outside alone to collect pebbles, but
the males did not suspect their female partners. According to the
observations and analysis made by Hunter, the prostitute penguins
targeted single males, because if instead they picked a male penguin
with a partner, the male penguin's current partner will come in conflict
with the prostitute female.
All that stuff about sitting on the egg waiting for their partners to
come back is less romantic when you know they're being cuckolded.
You're not a faithful husband penguin, you're a fool. While you're
making dinner for your unborn chick, your woman is out Roxanning it up
for building materials, perhaps sucking a macaque or two.
Today is a sad, sad day. Well, some day in 1998 was a sad day, but I've fallen behind on my penguin sex Wikipedia reading.
Thermal image of penguin. Credit:
Université de Strasbourg and Centre National de la Recherche
Scientifique (CNRS), Strasbourg, France
(Phys.org) —A research team made up of members from France
and the U.K. has discovered that when in cold temperatures, the outer
feathers of the emperor penguin are actually colder than the surrounding
air. As the team describes in their paper published in the journal Biology Letters,
they discovered the unusual thermal properties of the penguin's
feathers while studying the birds in their natural environment using
infrared imaging.
To gain a better understanding of how emperor penguins
are able to withstand extremely low temperatures for months at a time,
the research team ventured down to Terre Adélie, Antarctica, during June
2008. There they took hundreds of infrared thermal images
of penguins that had moved slightly apart from the others—that allowed
for full body images to be taken and minimized the collective warming
that occurs as the animals huddle together.
Upon examining the multicolored images, the researchers were
surprised to discover that the outer feathers that cover most of the
penguins' body, were actually four to six degrees Celsius colder than
the surrounding air. With most other birds, and animals, the air around
their bodies is warmer. The researchers explain that the apparent
anomaly appears to be due to what they describe as "extreme radiative
cooling." It's similar to frost building up on surfaces on a cold
morning. It happens with the penguins when their protective coat
radiates more heat into the colder sky than is absorbed from the
surrounding air—this causes the temperature at the surface of their
feathers to fall below that of the surrounding air. The end result, the
researchers report, is that the penguins are able to draw very tiny
amounts of heat back to their feathers from the surrounding air, helping
them to conserve energy. It's not much, the researchers conclude, but
when trying to survive in a very cold climate for very long periods of time, every little bit helps.
In looking at the thermal images, the researchers also noted that the
birds do have a few "hot" spots—eyes, beak and feet, where heat
escapes. The eyes in particular, bright red in the photos, suggest that
penguins must take care to protect such vulnerable areas from bitter
wind. They note that earlier studies have found that the more at-risk
areas of the penguins' body have special blood vessels that help to
conserve heat.
More information: Emperor penguin body surfaces cool below air temperature, Published online Biology Letters, March 6, 2013. doi: 10.1098/rsbl.2012.1192
Abstract
Emperor penguins Aptenodytes forsteri are able to survive the harsh
Antarctic climate because of specialized anatomical, physiological and
behavioural adaptations for minimizing heat loss. Heat transfer theory
predicts that metabolic heat loss in this species will mostly depend on
radiative and convective cooling. To examine this, thermal imaging of
emperor penguins was undertaken at the breeding colony of Pointe
Géologie in Terre Adélie (66°40′ S 140° 01′ E), Antarctica in June 2008.
During clear sky conditions, most outer surfaces of the body were
colder than surrounding sub-zero air owing to radiative cooling. In
these conditions, the feather surface will paradoxically gain heat by
convection from surrounding air. However, owing to the low thermal
conductivity of plumage any heat transfer to the skin surface will be
negligible. Future thermal imaging studies are likely to yield further
insights into the adaptations of this species to the Antarctic climate.
Those goodbye hugs at the train station or quick kisses in the park may
have deep evolutionary roots. Such public displays of affection may
help pair-bonded couples invest more in their children, boosting the
offspring's survival odds, new research suggests.
The study, published today (Feb. 19) in the journal Proceedings of the
Royal Society B, finds that when monogamous animals such as birds
continue their displays after mating, they put more energy into
parenting and can have more children than when they drop the displays.
Lifelong mates
Birds and other animals use showy feathers or elaborate courtship behaviors such as mating dances to lure potential partners.
But in the early 1900s, biologist Julian Huxley noticed that birds known as Great Crested grebes
rise up out of the water like synchronized swimmers with weeds in their
beaks. They continued this elaborate mating ritual, which Huxley
likened to humans holding hands or kissing, even after mating.
That begged the question: Why would monogamous animals have evolved to continue these display once they'd paired up?
"It's very obvious why you'd want a display to attract a mate, but once
you've already secured a mate, why should you bother to keep
displaying?" said study author Maria Servedio, an evolutionary biologist
at the University of North Carolina, Chapel Hill.
After all, bright colors and public displays of affection are
energetically costly and make animals more visible to predators. The
evolutionary benefits have to outweigh the costs for animals or they
wouldn't bother.
Helping the kids
To find out, Servedio and her colleagues looked at existing studies
from the animal kingdom. They noted that in monogamous species,
paired-up animals are better at raising more offspring. In other words,
two individual birds may be able to raise one chick at a time, but a
couple can raise more than two chicks together.
The researchers also found that, in other studies, when researchers
covered up mating displays like a bright red spot on a bird's bill, the
animals' partners invested less in offspring, Servedio told LiveScience.
Emphasizing an animal's display also seemed to increase its investment
in offspring.
Researchers then used a mathematical model to see if those two effects
could make displays that continue through a pair-bonded relationship
evolutionarily beneficial. The scientists found that this was in fact
true, because the displays made couples more likely to invest in their
offspring, increasing their reproductive fitness.
Human effect?
The findings suggest that monogamous animals
like humans snuggle, sport flashy feathers or canoodle on the subway
because it increases parents' investment in young, and thus, increases
the odds of these children surviving.
"This study points out a fascinating potential for these mutual
displays to be adaptive in terms of gains in parental investment by both
sexes," Rebecca Safran, an evolutionary biologist at the University of
Colorado, Boulder, who was not involved in the study, wrote in an email.
While its implications are most obvious for birds, "it is not such a
long stretch to imagine this process at work in human populations. The
trick is that the signals used by humans to stimulate additional
parental care would likely differ by culture and social context," Safran
said.
JOHN KIRK-ANDERSON/Fairfax NZ
Amateur fossil hunter Al Mannering, who discovered the skull
of the world's oldest penguin, left, which is shown compared with a
modern penguin.
The skull of a 65-million-year-old penguin which spent the last
decade wrapped in newspaper in a Christchurch garage could unlock the
secrets of the bird's evolution. Canterbury Museum scientists are analysing the new fossil of Waimanu manneringi, named after the Christchurch amateur fossil hunter who was the first to find bones from the world's oldest penguin.
Al Mannering, who first found fossils of the bird at the Waipara
River in 1997, made the new find in 2003 but did not realise its
significance until preparing it late last year. 'I wrapped it in newspaper and left it in my garage for 10 years, then last year I thought, 'I'd better have a go at that. Once I realised what it was, I emailed [the museum] straight away.''
Canterbury Museum senior curator Paul Scofield said the fossil, from the Paleocene era, was in ''exceptional'' condition. ''On a worldwide basis, it would be as good as fossils of this age get.'' Scofield said the skull was one of the most important parts of the
body for paleontologists, providing valuable hints about the bird's
history and its connection to other penguins.
Museum scientists would compare the skull with those of thousands of
other penguins to develop a ''family tree'' and determine how the bird
related to both modern penguins and the dinosaurs. The researchers would also do a CT scan of the skull at Christchurch
Hospital, allowing them to reconstruct its brain and outline its
abilities and lifestyle. ''As birds become specialists in flight or diving, it changes the
way their brain works: now we can start to make guesses at how these
animals actually lived,'' Scofield said.
The museum would work with American scientists from the University
of Texas who had found similar fossils in South America, which had
recently separated from New Zealand at the age the fossils dated back
to. ''It's a really sexy field in paleontology, because penguins were one of the earliest bird groups to evolve.''
Scofield said the Paleocene era was ''absolutely crucial'' to
scientific understanding of modern birds and mammals, due to dramatic
change which occurred during the period. ''As soon as we became free of dinosaurs, evolution went crazy,'' he said.
About 15 feet tall and 40 feet long, Tyrannosaurus rex,
whose name means “king of the tyrant lizards,” is one of the largest
known land predators to ever roam the Earth.
