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There are more than 200 species of noctilionoid bats, mostly in the American tropics. And despite being close relatives, their jaws evolved in wildly divergent shapes and sizes to exploit different food sources. A paper published Aug. 22 in Nature Communications shows those adaptations include dramatic, but also consistent, modifications to tooth number, size, shape and position. For example, bats with short snouts lack certain teeth, presumably due to a lack of space. Species with longer jaws have room for more teeth — and, like humans, their total tooth complement is closer to what the ancestor of placental mammals had.

A pair of studies published April 14 in the journal Science paint a new picture about apes, ancient Africa and the origins of humans. Many scientists had once hypothesized that the first apes to evolve in Africa more than 20 million years ago ate primarily fruit and lived within the thick, closed canopy of a nearly continent-wide forest ecosystem. Instead, the new research indicates that early apes ate a leafy diet in a more arid ecosystem of varyingly open woodlands with abundant grasses.

1 in 5 adult female white-necked jacobin hummingbirds look like males. New research from the University of Washington shows that this is a rare case of “deceptive mimicry” within a species: Females with male-like plumage are trying to pass themselves off as males, and as a result receive a benefit in the form of reduced aggression from males.

Which group of mammals has the more “primitive” reproductive strategy — marsupials, with their short gestation periods, or humans and other placental mammals, which have long gestation periods? For decades, biologists viewed marsupial reproduction as “more primitive.” But University of Washington scientists have discovered that a third group of mammals, the long-extinct multituberculates, had a long gestation period like placental mammals. Since multituberculates split off from the rest of the mammalian lineage before placentals and marsupials had even evolved, these findings question the view that marsupials were “less advanced” than their placental cousins.

Many animals have tusks, from elephants to walruses to hyraxes. But one thing tusked animals have in common is that they’re all mammals — no known fish, reptiles or birds have them. But that was not always the case. In a study published Oct. 27 in the Proceedings of the Royal Society B, a team of paleontologists at Harvard University, the Field Museum, the University of Washington and Idaho State University traced the first tusks back to dicynodonts — ancient mammal relatives that lived before the dinosaurs.

A team of paleontologists from the University of Washington and its Burke Museum of Natural History and Culture excavated four dinosaurs in northeastern Montana this summer. The four dinosaur fossils are: the ilium — or hip bones — of an ostrich-sized theropod, the group of meat-eating, two-legged dinosaurs that includes Tyrannosaurus rex and raptors; the hips and legs of a duck-billed dinosaur; a pelvis, toe claw and limbs from another theropod that could be a rare ostrich-mimic Anzu, or possibly a new species; and a Triceratops specimen consisting of its skull and other fossilized bones.

A study published Aug. 11 in the Proceedings of the Royal Society B by researchers at the University of Washington and Stony Brook University reports on how bats and pepper plants in Central America have coevolved to help each other survive.

New research by scientists at the University of Washington and Duke University is shedding light on how the nasal passage of dolphins and whales shifts during embryonic development from emerging at the tip of the snout to emerging at the top of the head as a blowhole. The findings, published July 19 in the Journal of Anatomy, are an integrative model for this developmental transition for cetaceans.

A new study led by paleontologists at the University of Washington indicates that the earliest evidence of mammal social behavior goes back to the Age of Dinosaurs. A multituberculate that lived 75.5 million years ago, Filikomys primaevus engaged in multi-generational, group-nesting and burrowing behavior, and possibly lived in colonies.

University of Washington scientists report evidence of a hibernation-like state in Lystrosaurus, an animal that lived in Antarctica during the Early Triassic, some 250 million years ago. The fossils are the oldest evidence of a hibernation-like state in a vertebrate, and indicate that torpor — a general term for hibernation and similar states in which animals temporarily lower their metabolic rate to get through a tough season — arose in vertebrates even before mammals and dinosaurs evolved.

Researchers at the University of Washington and the University of Idaho report that, for a bacterial pathogen already resistant to an antibiotic, prolonged exposure to that antibiotic not only boosted its ability to retain its resistance gene, but also made the pathogen more readily pick up and maintain resistance to a second antibiotic and become a dangerous, multidrug-resistant strain.

Scientists have discovered that the building blocks of proteins can stabilize cell membranes. This finding may explain how the first cells emerged from the primordial soup billions of years ago: The protein building blocks could have stabilized cell membranes against salt and ions that were present in ancient oceans. In addition, membranes may have been a site for these precursor molecules to co-localize, a potential mechanism to explain what brought together the ingredients for life.

A new study released July 1 in Nature Climate Change gives hope for coral reefs. Launched by the nonprofit Coral Reef Alliance, with lead and senior authors at the University of Washington, the study is one of the first to demonstrate that management that takes evolution and adaptation into account can help rescue coral reefs from the effects of climate change.

Old myths state that, during the time of the dinosaurs, mammals and their relatives were small and primitive. But new research shows that, during the time of the dinosaurs, mammals and their relatives actually underwent two large ecological radiations, diversifying into climbing, gliding and burrowing forms with a variety of diets.

A new study published April 30 in the Proceedings of the National Academy of Sciences identified three factors critical in the rise of mammal communities since they first emerged during the Age of Dinosaurs: the rise of flowering plants; the evolution of tribosphenic molars in mammals; and the extinction of non-avian dinosaurs, which reduced competition between mammals and other vertebrates in terrestrial ecosystems.

Here in what is called the Anthropocene era, humans and our urban environments appear to be driving accelerated evolutionary change in plants, animals, fungi, viruses and more — changes that could affect key ecosystem functions and thus human well-being. These interactions between evolution and ecology are called “eco-evolutionary feedback.” The National Science Foundation has awarded a five-year, $500,000 grant to a multi-institution research network team headed by Marina Alberti, University of Washington professor of urban design and planning, to advance…

Paleontologists picking through a bounty of fossils from Montana have discovered something unexpected — a new species of lizard from the late dinosaur era, whose closest relatives roamed in faraway Asia.

A new study by paleontologists at the Burke Museum of Natural History & Culture and the University of Washington describes an early marsupial relative called Didelphodon vorax that lived alongside dinosaurs and had, pound-for-pound, the strongest bite force of any mammal ever recorded.

University of Washington paleontologists have discovered a benign tumor made up of miniature, tooth-like structures embedded in the jaw of an extinct ‘mammal-like’ gorgonopsian. Known as a compound odontoma, this type of tumor is common to mammals today. But this animal lived 255 million years ago, before mammals even existed.

University of Washington biologist Dee Boersma and her colleagues combed through 28 years’ worth of data on Magellanic penguins to search for signs that natural selection — one of the main drivers of evolution — may be acting on certain penguin traits. As they report in a paper published Sept. 21 in The Auk: Ornithological Advances, selection is indeed at work on the penguins at the Punta Tombo breeding site in Argentina.

Faculty members from several departments at the University of Washington will share $2.25 million in research funds from the National Science Foundation to study and apply the principles of evolution “in real time.” Their studies are a part of the BEACON Center for the Study of Evolution in Action. Founded in 2010, this NSF science and technology center is a partnership among five universities to better understand evolutionary processes and apply concepts such as adaptation and selection to new and…

We’ve long known that humans and our cities affect the ecosystem and even drive some evolutionary change. What’s new is that these evolutionary changes are happening more quickly than previously thought, and have potential impacts not in the distant future — but now.

New work in Argentina where scientists had previously thought Earth’s first grasslands emerged 38 million years ago, shows the area at the time covered with tropical forests rich with palms, bamboos and gingers. Grit and volcanic ash in those forests could have caused the evolution of teeth in horse-like animals that scientists mistakenly thought were adaptations in response to emerging grasslands.