A new study suggests that even the smallest non-bird dinosaurs were unusually large due to ecological pressures, such as competition with early mammals. The findings also reveal that powered flight played a crucial role in allowing birds to evolve into tiny species, which is not seen in their dinosaur ancestors.
Researchers found that North American mammals expanded their range southward much earlier than thought, with identical fossils discovered in Mexico dating back to 10 million years ago. This 'holding pen' era primed the pump for intermittent exchange between 7 and 3 million years ago.
Mexico served as a long-term evolutionary hub where North American species adapted and diversified for millions of years before migrating to South America during the Great American Biotic Interchange. The findings suggest that prolonged diversification in Mexico contributed to the eventual prevalence of North American mammals in South ...
North and South American mammals interacted before the Panamanian land bridge formed, with evidence of North American animals clustering in southern Mexico around 7 million years ago. This research provides valuable insights into past environmental changes and biodiversity patterns.
A remarkably preserved Cretaceous mammal fossil in Mongolia's Gobi Desert is rewriting the chapter on mammal evolution. The discovery, published in Nature, reveals that zhelestids were not close relatives of modern placental mammals, but rather a distinct group of early mammals.
A new study reveals two recurring dental designs in mammals, optimizing for either cutting or crushing performance. The tradeoff between these abilities has shaped the evolution of carnassial teeth, influencing dietary adaptability.
A new study reveals that caregiving behaviors in ants are regulated by neural mechanisms that change over the course of an ant's lifetime. The researchers found two brain signaling molecules, Neuropeptide F and Allatostatin A, that act as opposing regulators of behavior, depending on the ant's internal state.
Research reveals birds can harness lactate to rapidly resurrect blood function, outperforming mammals. Lactate enables bird RBCs to convert methaemoglobin back to haemoglobin three times faster than mammalian RBCs.
Researchers at UT San Antonio develop non-toxic biologic to prevent Lyme disease transmission. The treatment targets small mammals and birds, reducing bacterial loads in ticks, and may soon be available for residential use.
A new study reveals that species with larger brains produce fewer but larger offspring, leading to the evolution of larger eggs. The research analyzed data from mammals, birds, and reptiles, suggesting that brain evolution drove changes in reproduction across dinosaurs and birds.
Researchers have sequenced and analyzed the two-toed sloth genome, discovering unique 'jumping genes' that are likely linked to their slow metabolism. These genes, which have been conserved over millions of years, may hold clues to understanding human health conditions such as diabetes, aging-related disorders, and muscle wasting.
A new study reveals that human childbirth is not the only mammalian experience with birth difficulties. Research shows that many other mammals, from domestic livestock to wild species, face similar complications and mortality rates. This challenges long-held assumptions about human childbirth being uniquely difficult.
A research team at HKUMed developed a machine-learning classifier that accurately predicts the potential risk of sustained mammalian transmission based on the influenza virus genomic content. The study found that reduced GC-related content in IAV genomes is associated with higher risk for human-to-human transmission.
A new study reveals that the disappearance of large mammals led to significant changes in food webs across different continents. The researchers found that regions with more severe past extinctions had distinct differences in their current mammal populations, indicating a lasting impact on food webs.
A new species of hamster-sized mammal, Cimolodon desosai, has been discovered in the Upper Cretaceous El Gallo Formation of Baja California. The fossil, estimated to be 75 million years old, was found alongside dinosaur fossils and provides insights into the survival strategies of early mammals.
A team of researchers discovered that the way cells sense oxygen determines if regeneration can even begin in mammalian limbs. They found that regenerative-competent amphibians show reduced oxygen-sensing capacity, while mammals respond strongly to oxygen and switch off regenerative programs.
A new study found that turtles' brains can detect unexpected visual stimuli independently of their position on the retina, a property previously thought to exist only in mammals. The researchers believe this ability helped animals understand their spatial environment, learn, and survive complex terrestrial environments.
A recent study found that seals near glacier fronts have fuller stomachs, indicating intense feeding activity. This discovery has implications for Arctic marine ecosystems as glaciers retreat and habitats disappear.
Scientists have developed a new way to identify and monitor small mammals using their footprints, tested on two near-identical species of sengi with 94%-96% accuracy. This technology can help reveal ecosystem health and provide a reliable metric for ecosystem integrity.
Researchers assessed olfactory abilities in extinct mammals like early whales, sabre-toothed cats, and Tasmanian tigers using skull and genetic studies. The study provides a reliable method for reconstructing the sense of smell in extinct species.
Researchers used engineering simulations to test the anatomy of a 250-million-year-old mammal and found that it likely had an eardrum large enough to hear airborne sound effectively. The study's findings challenge previous hypotheses on how early mammals heard, providing new insights into their evolution.
Dinosaurs operated with a 'latchkey kid' approach, with young offspring independent and foraging alone after just a few months. This led to an increased number of functional species in dinosaur fossil communities compared to modern mammals.
A recent study by Ocean Conservancy reveals that consuming as little as three sugar cubes' worth of plastics can be fatal to seabirds, while less than one-sixth of a soccer ball's worth can kill sea turtles. Marine mammals are also vulnerable, with nearly half dying from ingesting plastics, often of varying types.
A study of nine large mammal species in the Greater Yellowstone Ecosystem found that their behavioral responses to summer heat were influenced more by environmental structure than biological traits. Populations living in homogeneous environments altered their behavior more dramatically, seeking shade and cooler conditions.
A study by Max Planck Institute for Evolutionary Anthropology found that women generally outlive men, with females living 12% longer on average in most mammals. This gap is attributed to genetic differences, reproductive strategies, and parental investment, which provide a survival advantage to females.
Researchers tested a popular evolutionary theory by comparing maternal length and fetal sex in over 100,000 whales. They found that the fetal sex ratio skews female for longer body size, suggesting that female calves benefit more from heritable fitness than males do. The findings contradict the Trivers-Willard hypothesis.
Researchers propose a new concept, RNA immunity, which suggests small RNA molecules play a direct role in fighting viral infections in mammals. Endogenous and exogenous small RNAs can bind to viral RNA sequences and inhibit replication.
A new study found that mammals independently evolved specialized adaptations for exclusively feeding on ants and termites at least 12 times since the Cenozoic era began. This dietary strategy, called myrmecophagy, emerged following the K-Pg extinction and set the stage for ant and termite colonies to rapidly expand worldwide.
A microRNA discovered in male birds helps balance the activity of sex chromosomes, allowing for the survival of males despite genetic imbalance. This unique mechanism differs from mammals and highlights the diversity of evolutionary solutions to similar biological challenges.
Researchers have successfully enabled ear tissue regeneration in mice by flipping an evolutionarily disabled genetic switch involved in Vitamin A metabolism. By activating a key gene called Aldh1a2, the team restored regenerative ability in mice, which cannot regenerate complex tissues like the ear pinna.
A new study reveals smaller islands in Wallacea are critical refuges for endangered mammals, with lower genetic diversity but fewer harmful mutations. Habitat quality on these islands is higher than on larger ones, emphasizing the importance of protecting them for long-term survival.
Researchers analyzed fossil and living animal bones to reconstruct the path to upright posture, finding bursts of innovation and adaptive radiations. The study suggests that fully parasagittal postures evolved relatively late in mammalian history, contradicting previous theories.
Researchers analyzed over 200 species of tetrapods to understand mammalian posture evolution, finding that ancestral synapsids had a sprawling posture but distinct anatomy. The study suggests that parasagittal posture evolved late in synapsid evolution, around 100 million years ago.
A team of researchers from the University of Adelaide and other institutions has discovered a new sex-determination mechanism in monotremes, which include echidnas and platypuses. The AMHY gene plays a crucial role in determining sex in these animals, differing from the SRY gene found in all other mammals.
A new study found that mammals with bigger brains and more complex immune systems tend to live longer. The research suggests that the immune system plays a major role in driving the evolution of longer lifespans across mammals, removing aging and damaged cells, controlling infections, and preventing tumor formation.
A study by Swansea University reveals that native and invasive small mammals are sharing their gut microbes as habitats change, highlighting the importance of microbiome similarity in adaptation to new environments. This finding has implications for understanding the impact of urbanization on wildlife health and disease spread.
Researchers discovered a 'brinkmanship' game between rival genes in mammals that could explain why many fertilized eggs don't result in a new life. The study found that the stakes are raised, resulting in either the boldest gene triumphant or mutual self-destruction.
A global study using camera trap data from over 8.9 million images across 445 species in 38 countries found that many species do not stick to a single daily rhythm. Mammals' diel activity patterns are influenced by factors such as body size, location, and human presence, particularly in areas with higher human development.
A new study by UNC Greensboro researchers found that masked shrews reduce their body mass and braincase height by up to 13% during the colder months. The phenomenon, known as Dehnel's phenomenon, is a survival strategy used by some mammals to conserve energy in response to changing temperatures.
New research reveals mammals were shifting toward a more ground-based lifestyle several million years before the dinosaurs' mass extinction event. Analyzing small-fossilized bone fragments, scientists found signs of locomotory habit in end of limb bones from marsupial and placental mammals.
Gray seals possess the cognitive ability to perceive oxygen levels, regulating dive duration accordingly. Elevated CO2 levels do not impact dive duration, suggesting a separate mechanism for oxygen perception.
Early mammals that lived alongside dinosaurs were likely covered in dark and dusky greyish-brown fur, hinting at their ecological niche as nocturnal animals. Their pelage coloration played an important role in communication, camouflage, thermoregulation, and protection.
Two studies led by Dr. García-Moreno reveal birds' unique brain evolution, showing convergent evolution of neural circuits without homologous ancestors. Birds retained inhibitory neurons for hundreds of millions of years, while excitatory neurons evolved in new ways, highlighting the evolutionary flexibility of brain development.
Researchers have reconstructed the evolutionary origin of the complex configuration of multiple sex chromosomes in echidnas using their nearly gapless genome sequence. The high-quality data helped trace genetic events that led to this remarkable chromosomal arrangement, including chromosome fusion and fission events.
A nearly complete leg and well-preserved fossils from a small to medium-sized carnivorous animal were found in Mallorca. The discovery, dating back 270 million years, sheds light on the evolution of mammals.
A fossil therapsid was found in Mallorca with a skull hole for the jaw muscle and structures that evolved into mammals' middle ear bones. The discovery changes scientists' understanding of when therapsids evolved and tells us about where we come from.
A new study directly measures the hearing range of minke whales, revealing they can detect high-frequency sounds as high as 90 kHz. This discovery suggests baleen whales may be more impacted by ocean noise than previously thought and highlights the need for clearer thresholds to measure their sensitivity.
A new study published in Science Advances provides insights into the complex and nonlinear transition of mammal evolution from sprawled to upright posture. Researchers used cutting-edge methods to analyze fossil data and biomechanical modeling, revealing that locomotor performance peaked and dipped over millions of years.
Researchers discovered that bottlenose dolphins use the open mouth facial expression to signal playfulness and that they mirror each other's expressions 33% of the time. This finding suggests that visual communication plays a crucial role in shaping complex social interactions in marine mammals.
The study uncovers a 'mammalian-style' contact between the skull and lower jaw in a cynodont species, indicating that the defining mammalian jaw feature evolved multiple times in different lineages. This complex evolutionary history suggests that early mammals experimented with various jaw functions, leading to the evolution of 'mammal...
A review highlights gaps in data collection and testing mechanisms for H5N1 influenza transmission between cows and humans, posing risks of silent spread through farm worker barracks or developing countries. The authors emphasize the need for new control strategies, including vaccination, to mitigate the potential for a human pandemic
A new study reveals that a group of highly divergent mammals, including Afrotheria and distantly related, ecologically very similar mammals, independently evolved similar inner ear shapes. This suggests that neutral (non-adaptive) evolution may be more important in shaping inner ear morphology than previously thought.
Researchers found that cetaceans' backbones are highly regionalized, with a shift in vertebral column driving locomotion in aquatic environments. The team developed a computational software, MorphoRegions, to analyze the backbone of each specimen individually.
A new study from the Cusack group sheds light on how avian influenza virus can mutate to replicate in mammalian cells. The key enzyme polymerase must adapt to overcome two main barriers: entering and replicating within host cells, as well as acquiring human transmission capabilities.
Researchers analyzed fossilized tooth roots of ancient mammals, finding growth rings that revealed lifespans of eight to fourteen years. These early mammals grew more slowly but lived substantially longer than their modern descendants.
Researchers used synchrotron X-ray tomography to image growth rings in fossilized tooth roots, estimating lifespans and growth rates of early mammals. The study found that the modern mammal growth pattern emerged around 130 million years ago, with earlier animals growing more slowly and living longer.
Researchers found 16 native species of mammals using timber plantations as corridors and refuges in Central Panama. However, teak monocultures showed the lowest records of species, highlighting the importance of restoring natural habitats for comprehensive wildlife conservation.
A new study by North Carolina State University researchers found that climate was the most important factor in determining where mammals can thrive. Climate change will affect wildlife populations, and understanding these factors is crucial for making sustainable decisions about mammal population management.
A recent study published in Nature Communications found that mammals with more developed brains tend to exhibit smaller sexual size dimorphism (SSD), meaning there is less difference in size between males and females. This suggests that complex brain development may be linked to other traits such as social behavior and mate selection.
Researchers from the University of Washington have made significant advancements in understanding the evolutionary origins of flight in bats. The study, published in PeerJ Life & Environment, explores the transition from gliding to powered flight using phylogenetic comparative methods.