A single monitoring network developed by McGill, Natural Resources Canada, Université du Québec à Montréal (UQAM) and Dalhousie University researchers can simultaneously track earthquakes, water behaviour, human activity and whales, providing a comprehensive picture of what’s happening in, under, and at far distances from the water.

A mouse that lives higher than any other mammal has evolved unexpected adaptations that allow it to thrive from sea level to Andean summits, researchers report in a new study. According to the findings, the Andean leaf-eared mouse uses a distinct combination of metabolic and genetic adaptations – including an unexpected ability to detoxify poisonous plants – to survive extreme environments. The Andean leaf-eared mouse (Phyllotis vaccarum) is the world’s highest-dwelling mammal and can be found living at elevations exceeding 6,700 meters above sea level. At these highest elevations, air temperatures remain almost permanently below freezing and oxygen levels are only about 44% of those at sea level, creating extreme physiological challenges for mammal survival. However, despite these conditions, leaf-eared mice thrive, occupying habitats spanning from sea level to high-elevation mountain summits. The adaptations that enable this species uniquely to live in such an incredible range of environments, including the thin, freezing air of the Andes, aren’t well understood. Here, Schuyler Liphardt and colleagues analyzed whole-genome sequence data for 167 leaf-eared mice collected from locations across the species’ elevational range. Specimens were collected during 5 extreme high-elevation expeditions in the central Andes and additional low- to mid-elevation surveys. Liphardt et al. compared animals from high elevations with mice from lower elevations and a closely related lowland species. Through laboratory experiments that simulated cold, low-oxygen conditions, they found that high-elevation mice generated significantly more body heat and showed greater activity in both their muscles and heat-producing brown fat, reflecting an enhanced ability to stay warm despite the lack of oxygen. Surprisingly, these mice did not rely on many of the oxygen-transport adaptations seen in other high-altitude mammals, such as changes in hemoglobin. Instead, they appear to depend on a different suite of physiological and genetic adaptations that improve energy production, regulate blood vessels, and help their bodies function under chronic oxygen deprivation. Population genomic analyses found that these adaptations in high-elevation mice are maintained despite substantial gene flow between highland and lowland populations. The authors also found that genomic structural variation does not appear to drive adaptation. Unexpectedly, genomic evidence revealed widespread selection on pathways involved in detoxifying plant-derived compounds, suggesting the species has also evolved the ability to metabolize toxic plants. This indicates that feeding ecology may play a much larger role in elevation-related adaptation than previously recognized.

A tiny mouse living nearly 7,000 metres above sea level in the Andes is helping scientists rethink the limits of life on Earth. 

The animal, a leaf-eared mouse, is the focus of a new international study co‑authored by McMaster University researchers, revealing how mammals can survive in conditions once thought uninhabitable. 

Despite domination of the cancer research world, mouse models fail to accurately mimic some human diseases, such as estrogen receptor-positive (ER+) breast cancer, which accounts for 70% of breast cancer cases. To address this problem, researchers used a genome editing method to generate rat models covering the most common ER+ breast cancer gene mutations. They found that the rat models closely mimic human disease biology, response to therapy and immune microenvironment.

The Sand Tiger Shark (Carcharias taurus) is a globally critically endangered shark that is one of the most popular sharks to display in aquariums. The Northwest Atlantic population is considered one of the least threatened populations of Sand Tiger Sharks, largely due to effective fisheries management in the U.S. However, there has never been a formal stock assessment for this population, nor has there been any recent assessment of its population trends, so its population status remains unknown. Despite these issues, there remains a strong financial incentive to collect wild sharks for display in aquariums around the world. The impact that these collecting activities have on the Northwest Atlantic population is unknown and therefore raises questions as to why private organizations are permitted to harvest a protected species for profit without understanding the impact this activity has on wild populations or without directly contributing to their conservation. In this paper, researchers describe this situation and highlight some of the biological, ethical, and financial concerns associated with harvesting a protected species for profit, thereby hindering the conservation and recovery of Sand Tiger Shark populations.