Results 41 to 50 of about 3,555 (176)

The “costly son” hypothesis: Sons exacerbate obstetrical dilemmas in humans and other mammals

The Anatomical Record, EarlyView.
Abstract Human childbirth has often been considered uniquely difficult among mammals, yet recent evidence suggests that obstructed labor and fetopelvic disproportion are widespread across placental mammals. Here, we propose the “costly son” hypothesis: because male offspring are typically larger at birth, they impose greater obstetric risk on mothers ...
Nicole D. S. Grunstra, Jonathan C. K. Wells   +1 more
wiley   +1 more source

Plastic pollution is killing marine megafauna, but how do we prioritize policies to reduce mortality?

Conservation Letters, 2021
Pollution by plastic and other debris is a problem affecting the world's oceans and is increasing through time. The problem is so large that prioritizing solutions to effect meaningful change may seem overwhelming to the public and policy makers.
Lauren Roman, Qamar Schuyler, Chris Wilcox, Britta Denise Hardesty   +3 more
doaj   +1 more source

Zooarchaeology of Houses and Middens: Investigating Patterns of Assemblage Composition at Early Inuit Sites Across the North American Arctic

International Journal of Osteoarchaeology, EarlyView.
ABSTRACT This study examines faunal assemblages from paired semisubterranean houses and middens at 10 Early Inuit sites spanning the North American Arctic (ca. 1200–1500 ce) to evaluate whether local resource bases or other factors primarily structure zooarchaeological variability.
Lauren E. Y. Norman, T. Max Friesen, Sean P. A. Desjardins   +2 more
wiley   +1 more source

Heavy metal contamination in pristine environments: lessons from the Juan Fernandez fur seal (Arctocephalus philippii philippii)

Royal Society Open Science, 2023
Heavy metals, including mercury (Hg) and cadmium (Cd), occur naturally or anthropogenically and are considered toxic to the environment and human health. However, studies on heavy metal contamination focus on locations close to industrialized settlements,
Constanza Toro-Valdivieso, Ravin Jugdaohsingh, Jonathan J. Powell, Joseph I. Hoffman, Jaume Forcada, Charles Moore, Barbara Blacklaws   +6 more
doaj   +1 more source

Blubber Thickening Driven by UCP1 Inactivation: Insights from a Cetacean‐Like Transgenic Mouse Model

Integrative Zoology, EarlyView.
UCP1 inactivation of cetaceans in mice drives BAT whitening and iWAT hyperplasia, promoting fat accumulation for aquatic adaptation. Abstract Cetaceans possess thick blubber, a specialized adipose tissue essential for thermal insulation, a streamlined body form, energy storage, and buoyancy. However, the mechanisms that underpin this adaptation are not
Qian Zhang, Yuehua Wang, Hang Zhang, Guiping Xu, Shixia Xu, Guang Yang   +5 more
wiley   +1 more source

Large‐scale molecular barcoding of prey DNA reveals predictors of intrapopulation feeding diversity in a marine predator

Ecology and Evolution, 2020
Predator–prey interactions are critical in understanding how communities function. However, we need to describe intraspecific variation in diet to accurately depict those interactions.
Madelyn R. Voelker, Dietmar Schwarz, Austen Thomas, Benjamin W. Nelson, Alejandro Acevedo‐Gutiérrez   +4 more
doaj   +1 more source

Variation in body size of ringed seals (Pusa hispida hispida) across the circumpolar Arctic: evidence of morphs, ecotypes or simply extreme plasticity?

Polar Research, 2021
The ringed seal is a small phocid seal that has a northern circumpolar distribution. It has long been recognized that body size is variable in ringed seals, and it has been suggested that ecotypes that differ in size exist.
Kit M. Kovacs, John Citta, Tanya Brown, Rune Dietz, Steve Ferguson, Lois Harwood, Magali Houde, Ellen V. Lea, Lori Quakenbush, Frank Riget, Aqqalu Rosing-Asvid, Tom G. Smith, Vladimir Svetochev, Olga Svetocheva, Christian Lydersen   +14 more
doaj   +1 more source

Sensory Biology of the Franciscana (Pontoporia blainvillei, Pontoporiidae, Cetartiodactyla): Ontogenetic Modifications of Vibrissae and Vibrissal Crypts

Integrative Zoology, EarlyView.
The transition of cetaceans from a terrestrial to an aquatic environment involved a crucial sensory adaptation to environments with limited visibility. Vibrissae, important mechanoreceptors, undergo an ontogenetic transformation in odontocetes. This research describes the histomorphology of vibrissae and crypts at different developmental stages ...
Cecilia Mariana Krmpotic, Cleopatra Mara Loza, Alejo Carlos Scarano, Pedro Fernando Andrés‐Laube, Francisco Acuña, Juan Pablo Loureiro, Carolina Natalia Zanuzzi, Nicolás Nahuel Castro, María Teresa Pombo, Lorenzo von Fersen, Claudio Gustavo Barbeito   +10 more
wiley   +1 more source

Elevated antioxidant defence in the brain of deep-diving pinnipeds

Frontiers in Physiology, 2022
While foraging, marine mammals undertake repetitive diving bouts. When the animal surfaces, reperfusion makes oxygen readily available for the electron transport chain, which leads to increased production of reactive oxygen species and risk of oxidative ...
Gerrit A. Martens, Lars P. Folkow, Thorsten Burmester, Cornelia Geßner   +3 more
doaj   +1 more source

Comparative Genomics and Functional Evidence for Convergent Adaptation to Hypoxia in Mammals

Integrative Zoology, EarlyView.
This study reveals convergent selection in mammals adapted to hypoxia. Functional assays demonstrate that amino acid mutations reduce oxidative stress, attenuate hypoxia‐induced injury, and modulate the hypoxia‐inducible transcription factor (HIF)‐driven hypoxic response.
Hao Dong, Chunxu Wang, Enqing Pei, Liang Zhao, Simin Chai, Ran Tian   +5 more
wiley   +1 more source