13 posts · 2,482 views
About Animals / Wildlife is a blog that explores a wide range of research topics about animals of all sizes, shapes, and demeanors, from mites to blue whales.
Laura Klappenbach
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- December 14, 2009
- 11:15 AM
- 135 views
Bird Calls: Scolding Predators or Warning Fellow Birds?
by Laura Klappenbach in About Animals / Wildlife
When approached by a predator, birds often cry out—they produce what is known as a 'call'. But why would a bird do such a thing? A call draws attention to the caller and might reveal it's location, making it more vulnerable to attack. What is the purpose of such a risky vocal outburst? And when a bird calls out, to whom is the bird communicating? Predators or fellow birds?
A team of scientists from the University of California Davis conducted a series of experiments to find out more about the motives behind bird calls. They caught an assortment of wild birds—dark-eyed juncos, yellow-rumped warblers, house finches. They placed the birds in a birdcage around which they set up a ring of microphones. The researchers then tricked the caged birds into thinking a predator was in their midst by showing showed them a stuffed owl. The calls the birds made in response to the owl's appearance were recorded and analyzed.
Read more...Bird Calls: Scolding Predators or Warning Fellow Birds? originally appeared on About.com Animals / Wildlife on Monday, December 14th, 2009 at 16:15:41.Permalink | Comment | Email this... Read more »
Yorzinski, J., & Patricelli, G. (2009) Birds adjust acoustic directionality to beam their antipredator calls to predators and conspecifics. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2009.1519
- December 3, 2009
- 09:04 PM
- 139 views
The Decline of the Megafuana
by Laura Klappenbach in About Animals / Wildlife
Something dramatic happened to a lot of very big animals between 20,000 and 10,000 years ago. During this time period, 34 major groups of large animals died-out. Among those that disappeared, were ten species that weighted more than a ton. Giant sloths, mammoths, mastodons, giant kangaroos, and moa were just a few of the fast-vanishing fauna.
It has long been clear that these large animals, also known as "megafauna", perished in a short period of time. But scientists disagree about what caused their rapid decline. One explanation was that the humans that moved into the area about 13,000 years ago hunted the large animals to extinction. Another eplanation attributes the decline of large animals to an extraterrestrial object hitting the earth about that same time.
To better understand what brought about the demise of large land animals, a team of scientists set out to reconstruct the ecosystems of the past. The team, led by Jacquelyn Gill of the University of Wisconsin, Madison, went to Appleman Lake in Indiana. There they sampled the sediments that lined the lake looking for clues about the animals and ecology that once thrived in that region.
Gill and her colleagues sought three basic artifacts: fungal spores, pollen, and charcoal. Each of these clues held different bits of information. The fungal spores, distributed in the dung of large herbivores, provided a way of estimating how many "mega" animals were present in the region (more spores meant more dung and more dung meant more animals). Pollen grains provided scientists with to reconstruct the type of vegetation that existed in the region. The third clue, charcoal, held information about the fires that raged (or didn't rage) through the region in prehistoric times. More charcoal meant more fires.
The data Gill and her team collected indicated that large animals started to disappear from the region 14,800 years ago. This finding was surprising, archeologists previously thought that humans did not arrive to the region until 13,300 years ago. Gill and her team also showed that the dominant habitat, open savanna, gradually gave way to mixed woodlands. Fires became increasingly more common, a measure of how dramatically the landscape was changing as the megafuana vanished.
Refs:
Gill, J., Williams, J., Jackson, S., Lininger, K., & Robinson, G. (2009). Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America Science, 326 (5956), 1100-1103 DOI: 10.1126/science.1179504
Johnson, C. (2009). Megafaunal Decline and Fall Science, 326 (5956), 1072-1073 DOI: 10.1126/science.1182770
Image courtesy of Barry Roal Carlsen / University of Wisconsin-Madison.
The Decline of the Megafuana originally appeared on About.com Animals / Wildlife on Friday, December 4th, 2009 at 02:04:02.Permalink | Comment | Email this... Read more »
Gill, J., Williams, J., Jackson, S., Lininger, K., & Robinson, G. (2009) Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America. Science, 326(5956), 1100-1103. DOI: 10.1126/science.1179504
Johnson, C. (2009) Megafaunal Decline and Fall. Science, 326(5956), 1072-1073. DOI: 10.1126/science.1182770
- November 29, 2009
- 12:28 PM
- 129 views
Leaf-cutting Ants Tend Vast Fungal Gardens
by Laura Klappenbach in About Animals / Wildlife
Leaf-cutting ants have the power to slice, dice, and pilfer the foliage of an entire grove of trees in a matter of days. With impressive efficiency, swarms of leaf-cutters clip and carry leafy material in vast quantities back to their subterrainean colony. There they process the clippings into compost piles, atop which the ants cultivate crops of fungi. The ants tend these fungal gardens and in return the fungi provide a constant source of food for the ant colony.
Leaf-cutter ants and their fungal crops are among the most impressive symbiotic pairings known in the animal kingdom. This ant-fungus relationship is estimated to be between 8 and 12 million years old. But leaf-cutting ants are not the only type of ants to rely on fungus as a food source. There are, in fact, over 230 species of fungus-farming ants, a group referred to as the "attine ants".
The first ants to cultivate fungal gardens lived over 50 million years ago. These ants practiced what is referred to as "lower agriculture", operating small-scale fungi gardens consisting of parasol mushrooms or coral fungi.
The symbiotic relationships in the lower agriculture systems are characterized by a looser symbiotic relationship than later evolving systems. Fungi in lower agricultural systems rely less on their ant hosts and can grow outside of the ant colony. Additionally, the ants are not as particular about the type compost they collect for their fungal garden. They don't harvest leave cuttings but instead settle for decaying material and insect feces.
The agriculture of later-evolving attine ants is more specialized though and their symbiosis with their cultivar is more intimately intertwined. These fungal species in these "higher agriculture" systems, including the fungi grown by leaf-cutting ants, must be tended by ants to ensure their survival. Additionally, the fungi pay the ants back well for their work by sprouting nutritious nodules called "gongylidia" that serve as a food source for the ants.
Refs:
Schultz, T., & Brady, S. (2008). From the Cover: Major evolutionary transitions in ant agriculture Proceedings of the National Academy of Sciences, 105 (14), 5435-5440 DOI: 10.1073/pnas.0711024105
Photos © Bandwagonman / Wikipedia.
Leaf-cutting Ants Tend Vast Fungal Gardens originally appeared on About.com Animals / Wildlife on Sunday, November 29th, 2009 at 17:28:03.Permalink | Comment | Email this... Read more »
Schultz, T., & Brady, S. (2008) From the Cover: Major evolutionary transitions in ant agriculture. Proceedings of the National Academy of Sciences, 105(14), 5435-5440. DOI: 10.1073/pnas.0711024105
- November 23, 2009
- 05:00 AM
- 2 views
Introducing the Magombera Chameleon
by Laura Klappenbach in About Animals / Wildlife
Attention all chameleon fans! It's official: there is now one more species of chameleon known to science. Meet the Magombera chameleon, aka Kinyongia magomberae, a small chameleon with a long tail and a delicate spattering of colors. Although most of its body scales are a soft grey-brown hue, this little lizard is far from dull.
... Read more »
MICHELE MENEGON, KRYSTAL A. TOLLEY, TREVOR JONES,, FRANCES COROVERO, ANDREW R. MARSHALL, & . (2009) A new species of chameleon (Sauria: Chamaeleonidae: Kinyongia) from the Magombera forest and the Udzungwa Mountains National Park, Tanzania. African Journal of Herpetology, 58(2), 59-70. info:/
- November 19, 2009
- 10:00 PM
- 147 views
Scorpionflies: The Oldest Known Animal Pollinators
by Laura Klappenbach in About Animals / Wildlife
A new study suggests that scorpionflies that lived during the Jurassic Period fed on the nectar-like juices of seed ferns, conifers, and other primitive plants. As the scorpionflies feasted on the sweet liquid from these plants, they may have also acted as animal pollinators—couriers of pollen grains that are vitally necessary to the reproductive cycle of their host plants. If this scenario is true, scorpionflies represent the earliest known animal pollinators.... Read more »
Ren, D., Labandeira, C., Santiago-Blay, J., Rasnitsyn, A., Shih, C., Bashkuev, A., Logan, M., Hotton, C., & Dilcher, D. (2009) A Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies. Science, 326(5954), 840-847. DOI: 10.1126/science.1178338
Ollerton J, & Coulthard E. (2009) Paleontology. Evolution of animal pollination. Science (New York, N.Y.), 326(5954), 808-9. PMID: 19892970
- September 22, 2009
- 05:30 AM
- 288 views
Photo Monitoring Ningaloo's Whale Sharks
by Laura Klappenbach in About Animals / Wildlife
Whale sharks are anything but camera shy. Between 1995 and 2006, scientists, tourists, divers, and tour guides snapped more than 5100 underwater photographs of these gentle giants at Ningaloo Marine Park, off the coast of Western Australia. The photographs weren't random portraits of fish. They were all captured as part of a long-term survey of the region's whale sharks.... Read more »
Holmberg J, Norman B, & Arzoumanian Z. (2008) Robust, comparable population metrics through collaborative photo-monitoring of whale sharks Rhincodon typus. Ecological applications : a publication of the Ecological Society of America, 18(1), 222-33. PMID: 18372568
- September 17, 2009
- 12:45 AM
- 280 views
Scanning DNA Barcodes in Sea Turtles
by Laura Klappenbach in About Animals / Wildlife
Little chunks of DNA can act as unique barcodes that enable scientists to identify an organism. This fact, which underpins a scientific technique known as DNA barcoding, is now helping conservationists who want to better understand sea turtles, a threatened group of marine reptiles. Since sea turtles are pelagic (they roam the open ocean and migrate vast distances), they are notoriously challenging study subjects. DNA barcoding of sea turtles offers clues about their diversity and in turn reveals the effects trends such as climate change, habitat destruction, and bycatching are having on them.... Read more »
NARO-MACIEL, E., REID, B., FITZSIMMONS, N., LE, M., DESALLE, R., & AMATO, G. (2009) DNA barcodes for globally threatened marine turtles: a registry approach to documenting biodiversity. Molecular Ecology Resources. DOI: 10.1111/j.1755-0998.2009.02747.x
- September 8, 2009
- 02:33 PM
- 235 views
Rare Freshwater Fish Hold Clues to Conservation
by Laura Klappenbach in About Animals / Wildlife
As the saying goes, there are lots of fish in the sea. But that's only a half-truth. Scientifically speaking, there are also lots of fish in rivers, lakes, streams and ponds as well. Of the more than 32,500 species of fish, 43 percent inhabit freshwater habitats. Taking into account the fact that the water held in rivers, lakes, streams and ponds accounts for only a tiny fraction of the Earth's water—a mere 0.01 percent—freshwater fish are exceptionally diverse.... Read more »
Magurran, A. (2009) Threats to Freshwater Fish. Science, 325(5945), 1215-1216. DOI: 10.1126/science.1177215
- September 8, 2009
- 02:45 AM
- 252 views
Young Lemon Sharks Stay Close to Home
by Laura Klappenbach in About Animals / Wildlife
It seems young lemon sharks that live in the waters around the Bahamas are homebodies. Recent research has revealed that these "teenage" sharks stay close to their birthplace as they mature. Previously, little was known about the wanderings of the sharks after they reached 3 years of age. Scientists were uncertain whether they dispersed into new territory as they gained experience or if they lingered close to their nursery sites. These new findings reveal that more than half of teenage lemon sharks hang-out in the waters near their former nurseries.... Read more »
CHAPMAN, D., BABCOCK, E., GRUBER, S., DIBATTISTA, J., FRANKS, B., KESSEL, S., GUTTRIDGE, T., PIKITCH, E., & FELDHEIM, K. (2009) Long-term natal site-fidelity by immature lemon sharks ( ) at a subtropical island . Molecular Ecology, 18(16), 3500-3507. DOI: 10.1111/j.1365-294X.2009.04289.x
- August 26, 2009
- 12:52 AM
- 228 views
Big Fish, Global Fish
by Laura Klappenbach in About Animals / Wildlife
Scientists have discovered that whale sharks, the largest fish in the sea, all belong to one big school. Instead of breaking down into lots of little social groups scattered throughout their range, whale sharks around the world intermix in a single, widespread breeding population. This is pretty impressive, considering the range of whale sharks stretches in a broad band around the planet's belly that includes the tropical and warm temperate seas between 30°N and 35°S.... Read more »
Schmidt JV, Schmidt CL, Ozer F, Ernst RE, Feldheim KA, Ashley MV, & Levine M. (2009) Low genetic differentiation across three major ocean populations of the whale shark, Rhincodon typus. PloS one, 4(4). PMID: 19352489
- August 3, 2009
- 12:30 PM
- 209 views
Rats! Are Rodents Getting Bigger?
by Laura Klappenbach in About Animals / Wildlife
It's the stuff of low-budget sci-fi movies: rodents around the globe are growing ever larger at astonishing rates. But B movie it's not—as UIC ecologist Oliver Pergams has demonstrated, the trend is real. In a recently published report Pergams details how rodents are showing signs of rapid, worldwide changes in size and shape. Of course, the timescale and magnitude of this size change is not alarming enough to cause movie-goers to flee the cinema (we're talking about decades and millimeters here—and in some cases size decreases were observed). But it is significant enough to capture the attention of scientists and to merit further investigation into its causes.... Read more »
Pergams, O., & Lawler, J. (2009) Recent and Widespread Rapid Morphological Change in Rodents. PLoS ONE, 4(7). DOI: 10.1371/journal.pone.0006452
- August 1, 2009
- 10:51 PM
- 216 views
Are Jellyfish Mixing Up the Oceans?
by Laura Klappenbach in About Animals / Wildlife
In the world's oceans, water circulates in currents that stretch between the continents and glide along coastlines. Water from the deep mixes with shallower water through vertical movements called upwellings and downwellings. This complex ebb, flow, rise, and fall of seawater—also known as ocean mixing—transports energy, churns nutrients, and stirs dissolved gasses. To understand the driving forces behind ocean mixing is to understand a key element of marine environments.... Read more »
Katija K, & Dabiri JO. (2009) A viscosity-enhanced mechanism for biogenic ocean mixing. Nature, 460(7255), 624-6. PMID: 19641595
- July 25, 2009
- 12:55 AM
- 222 views
Heating Bills Help Keep Toucans Cool
by Laura Klappenbach in About Animals / Wildlife
Relative to its body size, the toco toucan dons the largest bill of any bird. This magnificent hood ornament serves the toucan well. It functions as a refined feeding tool that enables the toucan to skin fruit and snare prey. It can be wielded as a warning flag to discourage rivals and ward off predators. And, as Charles Darwin noted, the enormity of the toucan's beak may serve as a bright beacon of virility to potential mates.... Read more »
Tattersall, G., Andrade, D., & Abe, A. (2009) Heat Exchange from the Toucan Bill Reveals a Controllable Vascular Thermal Radiator. Science, 325(5939), 468-470. DOI: 10.1126/science.1175553
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