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Categories: Biology: Zoology, Paleontology: Dinosaurs

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Tropical Heliconius butterflies are well known for the bright colour patterns on their wings. These striking colour patterns not only scare off predators -- the butterflies are poisonous and are distasteful to birds -- but are also important signals during mate selection. Evolutionary biologists have now exploited the diversity of warning patterns of various Heliconius species to investigate the genetic foundations of these preferences. In the process, the scientists identified a gene that is directly linked to evolutionary changes in a visually guided behavior.

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Forests and streams are separate but linked ecosystems, existing side by side, with energy and nutrients crossing their porous borders and flowing back and forth between them. For example, leaves fall from trees, enter streams, decay and feed aquatic insects. Those insects emerge from the waters and are eaten by birds and bats. An international team has now found that these ecosystems appear to keep the energy exchanges in balance -- a finding that the scientists called surprising.

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The largest living animal, the blue whale (Balaenoptera musculus) which averages about 27 meters in length, has slowly recovered from whaling only to face the rising challenges of global warming, pollution, disrupted food sources, shipping, and other human threats. In a major new study, biologists have taken a stock of the number, distribution and genetic characteristics of blue whale populations around the world and found the greatest differences among the eastern Pacific, Antarctic subspecies and pygmy subspecies of the eastern Indian and western Pacific.

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Killer whales foraging in deep submarine canyons off the coast of California represent a distinct subpopulation that uses specialized hunting techniques to catch marine mammals, researchers report.

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Scientists found that farmed salmon production leads to an overall loss of essential dietary nutrients. They say that eating more wild 'feed' species directly could benefit our health while reducing aquaculture demand for finite marine resources.

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Dinosaurs get all the glory. But aetosaurs, a heavily armored cousin of modern crocodiles, ruled the world before dinosaurs did. These tanks of the Triassic came in a variety of shapes and sizes before going extinct around 200 million years ago. Today, their fossils are found on every continent except Antarctica and Australia.

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Heparin, the world's most widely used blood thinner, is used during procedures ranging from kidney dialysis to open heart surgery. Currently, heparin is derived from pig intestines, but scientists have discovered how to make it in the lab. They have also developed a path to a biomanufacturing process that could potentially revolutionize how the world gets its supply of this crucial medicine.

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Researchers have used a series of artificial stream channels to mimic the behavior of headwater creeks under future climate change scenarios. They found that drier conditions shifted the life cycles of the algae and insects that form the base of the alpine food web. However, because species adjusted to the shifts in a variety of ways, the stream ecosystems were generally resilient to the changing conditions.

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A new study shows how heteroresistance, a transient resistance common in many bacteria, can act as a precursor to the development of antibiotic resistance.

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A new study has found a decline in the abundance of marine fish species that move rapidly toward the poles to escape rising sea temperatures. The researchers explain that many animal species are currently moving toward cooler regions as a result of global warming, but the velocity of such range shifts varies greatly for different species. Examining thousands of populations from almost 150 fish species, the researchers show that contrary to the prevailing view, rapid range shifts coincide with widescale population declines.

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Scientists have discovered how female Diadem butterflies have evolved to look like African Queen butterflies to repel predators.

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A new visitor was reported on the coast of Cyprus, thanks to the growing power of citizen science. Researchers collected information and specimens through personal communication with amateur naturalists, but also through the internet, in order to compose the mosaic of repeated appearances of a giant water bug on the eastern shoreline of the island.

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One of the largest studies on wildlife activity reveals that wild animals react differently to humans depending on where the animals live and what they eat. Bigger herbivores -- plant-eating animals like deer or moose -- tend to become more active when humans are around, while meat-eaters like wolves or wolverines tend to be less active, preferring to avoid risky encounters.

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Acoustic recordings of a colony of little auks reveal their nocturnal activities and offer valuable monitoring means for avian biology in the Arctic.

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Researchers believe a group of killer whales observed hunting marine mammals including sperm whales, as well as a sea turtle, in the open ocean off California and Oregon could be a new population. Based on available evidence, the researchers posit that the 49 orcas could belong to a subpopulation of transient killer whales or a unique oceanic population found in waters off the coast of California and Oregon.

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A new study provides groundbreaking findings that offer insights on the migration and foraging patterns of leatherback sea turtles along the Northwest Atlantic shelf.

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Restored salmon habitat should resemble financial portfolios, offering fish diverse options for feeding and survival so that they can weather various conditions as the climate changes, a new study shows.

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We expect tropical animals to handle a certain degree of heat, but not wild swings in temperature. That seems to be true for tropical ectotherms, or 'cold-blooded' animals such as amphibians, reptiles, and insects. However, in a new study of 'warm-blooded' endotherms, a research team found tropical birds can handle thermal variation just fine.

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Researchers have discovered that some fish -- unlike humans -- do not need orexin to stay awake. This molecule was thought to be necessary for normal wake and sleep rhythms in vertebrates. Humans without orexin suffer from narcolepsy.

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Dairy cows receive a huge amount of care during their lives on a farm, but procedures, especially restraining during procedures, can be stressful for some animals. Positive reinforcement training -- or training with a reward to achieve a desired behavior -- has shown promise to reduce this fear in other species.