Welcome back to science news! This week we’ve got stealthy dinosaurs, good news about manatee numbers, the Mississippi River flowing backwards, and a pitcher plant with a totally batshit food source.
A small species of dinosaur called Sinocalliopteryx may have hunted like modern cats. Two fossil specimens were found with the remains of their last meal still in their stomachs; one had just eaten a feathered flying dinosaur called Sinornithosaurus and the other had eaten two Confusciusorni, primitive birds about the size of a crow. Researchers speculate that they were able to catch flying dinosaurs and early birds by stalking their prey and leaping to catch them in flight, though others say there isn’t enough evidence to say for sure and that they may have been scavengers.
New DNA evidence shows that ancient humans mated not only with Neanderthals, but also with a small group of now-extinct hominids known as Denisovans. Not much is known about the Denisovans, as the only evidence of their existence is a tiny finger bone and two teeth found in a Siberian cave. Scientists didn’t even know the bones weren’t human or Neanderthal until they looked at a small section of their DNA in 2010 and realized it didn’t match either species. New sequencing techniques have allowed them to recreate the full genome of the individual whose bones were found; she appears to have had dark skin, brown hair, and brown eyes, but little else of her physical features can be known unless more fossils are found. Traces of Denisovan DNA can be found in the genomes of modern Melanesians, Papuans, Australian aborigines, and other South-East Asian islanders, but not in the peoples native to mainland Asia where the bones were found, leading to questions about the migration patterns of ancient humans. It appears that the group that interbred with Denisovans moved south and that the region was repopulated by later migrants.
Why are human babies so helpless when they’re born? Scientists have long contended that our enlarged brains are to blame; that in order for infants to gestate long enough for their brains to mature to a comparable level to other primates at birth, women’s pelvises would be so wide as to make it impossible to walk upright. However, new studies show that average pelvis widths would only need to be 3cm larger to accommodate the increased growth of a child born at 18 to 21 months gestation, and that such a small difference has no adverse effect on walking or energy expenditure. It’s actually the mother’s metabolism that couldn’t handle such a long pregnancy, as the energy expenditure to sustain the fetus’s growth for up to an extra year would be enormous. There may also be cognitive benefits, since babies learn a lot by socializing and observing their environment in the first year of life. Whatever the reason, I’m very glad that I didn’t have to be pregnant for 18-21 months!
Human diseases are jeopardizing the reintroduction of rescued apes back into the wild. Since we’re so closely related, many infectious diseases can be passed from zookeepers and sanctuary workers to the apes in their care. Releasing infected apes runs the risk of spreading illnesses to wild populations, where the populations could be decimated. 58% of the chimps at two sanctuaries in Africa tested positive for carrying MRSA, a drug-resistant strain of staph bacteria that can be highly lethal. New protocols may be needed to ensure that sick apes aren’t allowed to spread disease, and workers may need to be more carefully screened for communicable diseases.
Gray wolves are being dropped from the endangered species list in Wyoming. It’s great that their numbers have rebounded in recent years, but removing this protection means that they can be hunted again, which could quickly drop their numbers. Wyoming has an estimated 270 gray wolves living outside of Yellowstone; the new rules mean they only need to maintain 100 animals including at least 10 breeding pairs. Environmentalists may sue to reinstate protections, but hunters want to be able to shoot any wolves they find killing cattle. At least the wolves will still be protected within some of Wyoming’s parks and Native American reservations.
Up to one fifth of invertebrate species may be in danger of extinction. Invertebrates, which are animals without a backbone and include all insects, mollusks, shellfish, and many other species, make up about 80% of all known animal species. Freshwater species are most at risk, largely due to pollution and habitat disruption, but little is known about most marine species so it’s hard to know how they’re faring overall.
An eyeless cave fish is making scientists rethink our vision of ancient geography. Gobies in Madagascar and Australia share a common ancestor and are more closely related to each other than any of the other goby species found around the Indian Ocean. The species most likely started to diverge when Gondwanaland broke apart millions of years ago. Our current understanding of the makeup of that landmass puts the Indian subcontinent between Australia and Madagascar, but no closely related gobies can be found there today. It’s possible that the ancestor spread across the portion of the supercontinent that became Antarctica and died off there as it moved south, or maybe Gondwanaland was organized in a different fashion than we think.
A rare species of anglerfish was filmed for the first time off the coast of California by scientists from the Monterey Bay Aquarium Research Institute (MBARI) using a remote controlled submersible. Very little was known about the species, which was first discovered in 1891 when it was collected off the coast of Panama and had mostly been seen since then when captured accidentally by fishing trawlers. It wasn’t seen alive until 2002. The video below was shot in 2010 but just released last week; six different anglerfish were spotted, with the younger ones being an unexpected blue color and the more mature fish being the bright red scientists had seen before. They get bonus points for being cute; most deep-sea fish are kinda terrifying.
Now for one of the weirdest symbiotic relationships I’ve ever heard of. In Brunei on the island of Borneo, Hardwicke’s woolly bats roost inside carnivorous Nepenthes hemsleyana, pitcher plants which use digestive fluids to “eat” small insects to be able to survive in nutrient-poor soils. A team from Germany’s University of WÃ¼rzburg decided to figure out why these two species pair up. It turns out that the bats fit perfectly inside the pitchers and can barely be seen from outside, protecting them from predators while they sleep, while the plants benefit from the nutrients the bats, ahem, “deposit” inside the pitchers. (I don’t know how I manage to track down so much poop news for you people. It’s a gift.)
A record number of manatees have been spotted off the coast of Belize, with aerial surveys counting 507 individuals, 10% of which were calves. The Antillean manatees who mostly live in the waters off Belize are endangered, so it’s encouraging to see so many. The aerial survey also gives researchers valuable information about where they tend to congregate, which is important to ensure their future protection from boat strikes and habitat pollution or destruction. Click the link for more pics!
Hurricanes appear to actually increase the birth rate of dolphins. Surveys in the Gulf of Mexico before and after Hurricane Katrina struck in 2005 show a huge increase in the number of babies spotted about two years after the storm. Many dolphins, especially juveniles, are killed during hurricanes, so it seems odd that in the long term they would be beneficial. Researchers think the increased birth rate is due to a number of factors: mothers whose babies are killed in the hurricane are able to breed again sooner than they would if they were still caring for a young one, and decreased commercial fishing in the Gulf after the storm led to more food being available for mothers and babies as well as safer conditions for dolphins, which no longer had to spend as much time avoiding boats.
Oil and gas drilling may soon be under way in the Arctic Ocean, as the Interior Department has given Shell permission to start the initial stages of setting up their first well off the coast of Alaska. While they aren’t allowed to actually drill for oil or gas yet, this step lets them start the preliminary steps to set up the well and install safety features, including a blowout preventer. Environmentalists are upset with the decision since a response plan for possible spills has not yet been approved.
The release of methane stored in arctic permafrost has been discussed as a potential future source of global warming, but it looks like Antarctica may hold up to ten times as much methane. Organic matter trapped under the ice may have been converted to methane by microbes, and since it’s relatively shallow, the melting of the ice sheet could release high quantities of the gas, warming the air even further.
As Hurricane Isaac came onshore last Tuesday, the combined force of its winds and the waves created by the storm caused the Mississippi River to flow backwards for 24 hours. On average, the river was 10′ higher than usual. This isn’t the first time the river has run inland; Hurricane Katrina pushed waters even higher in 2005 and in 1812 part of the river farther upstream reversed course for several hours after the New Madrid earthquake in Missouri.
NASA’s Wide-Field Infrared Survey Explorer (Wise) space telescope has found millions of previously unknown supermassive black holes and has given us new information about hot dust-obscured galaxies (hot-Dogs). These black holes and galaxies are hidden behind clouds of dust that block visible wavelengths, but by using heat wavelengths invisible to the naked eye, Wise was able to look through the dust. The hot-Dogs are especially interesting, as they are extremely rare, up to 100 trillion times brighter than our sun, and seem to have formed around black holes (whereas most galaxies develop supermassive black holes at their centers only after they’re formed).
A new kind of supernova has been discovered. White dwarf stars can explode into supernovae after absorbing material from other stars, but until now astronomers didn’t know what kind of stars they needed to be partnered with. Some guessed that a pair of white dwarves merging was the cause of the explosions, but evidence from a supernova first spotted in January 2011 shows that it may have orbited a red giant and that it was the absorption of gas from the giant that caused the star to explode.
Astronomers have discovered the first known binary star system with two orbiting planets. The Kepler-47 system consists of a star similar to our sun paired with a smaller partner. One small planet orbits very close to the pair, with a year lasting only 49.5 days, while the larger planet is in the habitable zone where temperatures are right for liquid water to form and orbits the suns in 303 days. It was only last year that a binary system was discovered with a single planet; until then it was thought that the gravitational forces around paired stars would be too strong for planets to form since it would be difficult for the dust cloud to form into a disc.
Finally, if you want to wake up really early tomorrow morning (Wednesday, September 5), NASA TV will broadcast a live spacewalk from the International Space Station. Coverage will start at 6:00 a.m. Eastern time, with the astronauts starting the spacewalk at 7:15. Flight Engineers Sunita Williams of NASA and Akihiko Hoshide of the Japan Aerospace Exploration Agency will be making a second attempt to replace a faulty Main Bus Switching Unit (MBSU), one of four main electrical power routing devices for the station. Good luck!