New research indicates that grey wolves are adapting their diets to consume harder foods, including bones, during warmer climate periods. The study, which analyzed wolf teeth from both historical and modern periods, suggests that warming temperatures and reduced snow cover are compelling wolves to adopt more energetically demanding feeding strategies, impacting their hunting success and nutrition acquisition. These findings emphasize the need to integrate climate considerations into long-term conservation strategies for large carnivores.
Study Highlights Dietary Shifts Across Time
A collaborative study led by the University of Bristol, in conjunction with the Natural History Museum, examined dietary changes in grey wolves across different climatic conditions. Published in Ecology Letters, the research utilized Dental Microwear Texture Analysis (DMTA) to analyze microscopic scratches and pits on wolf molars, which record an animal's diet in the final weeks or months of its life.
Researchers compared wolf teeth from three distinct periods:
- Approximately 200,000 years ago, a period characterized by summers similar to present day but colder winters.
- Approximately 125,000 years ago, an interglacial period with warmer summers and milder winters compared to current conditions.
- Modern-day wolves from Poland, an area experiencing warmer winters and decreasing snow cover.
The analysis revealed consistent patterns: wolves living in warmer climates consumed harder foods, a behavior known as durophagy, implying a more complete consumption of carcasses, including skeletal components.
Fossil wolves from the younger, warmer interglacial period exhibited consumption of harder foods compared to those from the older, colder interglacial period. Modern wolves in Poland displayed similar tooth wear patterns to their ancestors from the warmer interglacial period, suggesting they are also experiencing ecological stress due to ongoing climate warming.
Impact of Warming Winters on Wolf Ecology
Grey wolves typically thrive in cold, snowy winters. Deep snow can increase the vulnerability of herbivore prey by limiting their access to food and hindering their escape, while also aiding wolves in hunting due to their agility on snow and ice. Colder winters have historically correlated with heavier wolves and higher pup survival rates.
Warmer winters with reduced snow cover disrupt this dynamic, making hunting more challenging for wolves. This necessitates riskier or more energetically demanding feeding strategies, such as more extensive scavenging or consuming parts of prey typically avoided.
Lead author Dr. Amanda Burtt stated that the findings suggest wolves were exerting more effort to obtain nutrition during warmer climate periods.
In regions like Poland, wolves currently mitigate some climate-related stress by hunting deer and wild boar near agricultural areas and by scavenging roadkill. However, the study suggests that wolf populations inhabiting landscapes less affected by human activity may face greater challenges in the future due to limited access to these alternative food sources.
Implications for Conservation
The research highlights the importance of considering warming temperatures in wolf conservation planning.
Study co-author Dr. Neil Adams, Curator of Fossil Mammals, noted that while climate change is not globally listed as a primary threat to wolves, these investigations indicate it may be, particularly for remote populations.
The researchers conclude that climate change should be integrated into long-term conservation strategies for large carnivores, with future wolf conservation and reintroduction efforts incorporating considerations of snow cover and climate to ensure effectiveness.
The grey wolf, which evolved approximately 450,000 years ago, has experienced significant climatic changes throughout its history, including Ice Age cycles. These historical adaptations offer insights into how modern wolves may be affected by current and future climate change. Dr. Adams emphasized the value of leveraging fossil specimens in museum collections, some held for over 175 years, for conservation palaeobiology—an emerging field that applies insights from the fossil record to contemporary conservation issues.
The study received funding from the Natural Environment Research Council (NERC) and involved collaborators including the University of Warsaw, University of Leicester, and the British Geological Survey.