(Press-News.org) EAST LANSING, Mich. - High social status has its privileges -- when it comes to aging -- even in wild animals.
In a first-of-its-kind study involving a wild species, Michigan State University researchers have shown that social and ecological factors affect animal health. The results, published in the current issue of Biology Letters, focused on spotted hyenas in Kenya.
"High-ranking members in hyena clans reproduce more, they live longer and appear to be in better overall health," said Nora Lewin, MSU doctoral student of zoology and co-lead author. "If you want to see the hierarchy of spotted hyenas, throw down some fresh meat near them. It's quickly apparent who's dominant and who's not."
But Lewin wondered if long-accepted biological markers would support what she was seeing in the field. Thanks to working with fellow lead author Kay Holekamp, MSU zoologist, and her long-running hyena experiment, Lewin had access to more than 25 years of data and was able to spend a summer afield in Kenya, observing hyenas' social structure firsthand.
Lewin and her teammates focused on telomeres, caps at the end of each strand of DNA that protect chromosomes from deterioration. These biomarkers are regarded as important signs of aging and stress in many species, including humans. Shrinking telomeres are a signal that cells are sliding into defensive mode, stressful actions that could soon lead to cells' - and to the organism's - death.
High-ranking hyenas had longer telomeres than their subordinates. Group membership significantly predicted telomere length of those female hyenas that resided atop the social pyramid.
"This work shows, for the first time, the effects of social rank on telomere length in wild mammals," Lewin said. "This enhances our understanding of how social and ecological variables may contribute to age-related declines of hyenas, and in organisms in general."
Lewin also noted a couple of interesting twists. The alpha females of each clan had the longest telomeres. However, the length was relative to each individual clan. This means that if researchers found a lone hyena wandering the savanna, they couldn't simply identify it as an alpha female based solely on telomere length.
Also, the team was able to rule out a few factors that could possibly be influencing telomere length. Abundance of food, a seemingly obvious factor for overall health, did not influence the size of the biological marker.
"The fact that there is variation in telomere length when prey abundance is constant means that there are other factors we need to find," Lewin said. "We think it's less about genetics and more influenced by the environment, but we just need to keep searching for the right environmental factors."
INFORMATION:
Additional researchers from Bucknell University and Cornell University contributed to this study.
Holekamp's research is funded in part by the National Science Foundation and the National Institutes of Health. Holekamp and Lewin are participants in MSU's BEACON Center for the Study of Evolution in Action.
Michigan State University has been working to advance the common good in uncommon ways for more than 150 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world's most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.
For MSU news on the Web, go to MSUToday. Follow MSU News on Twitter at twitter.com/MSUnews.
WASHINGTON - Two patient groups created by the Affordable Care Act (ACA) - Medicare patients enrolled in federally designated patient-centered medical homes and people under age 26 who are allowed to remain on their parents' health insurance - had slightly fewer emergency department visits than they had before health care reform. However, there was no change in the rate of the most expensive types of emergency visits: those that lead to hospitalization.
One study examined the rate of emergency department visits and hospitalizations for Medicare patients treated by ...
Hurricanes require moisture, the rotation of the earth, and warm ocean temperatures to grow from a mere atmospheric disturbance into a tropical storm. But where do these storm cells originate, and exactly what makes an atmospheric disturbance amp up full throttle?
A new study published in Geophysical Research Letters by Tel Aviv University's Prof. Colin Price and his graduate student Naama Reicher of the Department of Geosciences at TAU's Faculty of Exact Sciences finds most hurricanes over the Atlantic that eventually make landfall in North America actually start as ...
WASHINGTON, March 12, 2015--Borrowing a trick from nature, engineers from the University of California at Berkeley have created an incredibly thin, chameleon-like material that can be made to change color -- on demand -- by simply applying a minute amount of force.
This new material-of-many-colors offers intriguing possibilities for an entirely new class of display technologies, color-shifting camouflage, and sensors that can detect otherwise imperceptible defects in buildings, bridges, and aircraft.
"This is the first time anybody has made a flexible chameleon-like ...
A QUT scientist has helped unravel the way in which plants regulate their levels of vitamin C, the vitamin essential for preventing iron deficiency anaemia and conditions such as scurvy.
Professor Roger Hellens, working with Dr William Laing from New Zealand's Plant and Food Research, has discovered the mechanism plants use to regulate the levels of Vitamin C in each of their cells in response to the environment.
"Understanding these mechanisms may help in plant breeding programmes to produce hardier plant crops and improve human health because iron deficiency anaemia ...
This news release is available in German. Simulations of impressive landscapes and alien creatures have become commonplace, especially in fantasy and science fiction films. But simulations are also appearing in ever more medical and engineering applications. However, the road to a perfect illusion is complex and time-intensive. Nils Thürey, professor at the Technische Universität München and his colleagues have developed a methodology that could accelerate these calculations.
The attack takes place at the climax of the blockbuster "Avatar": Rockets slam ...
"When I interviewed inspectors they are surprisingly open about this. They tell me that they get a box of fish or just some money from fishermen in exchange for being allowed to break the rules that apply to protected areas or catches," says Aksel Sundström.
Many of South Africa's marine fish stocks are overexploited. At the same time, the government actors that are meant to ensure that fishers abide to rules may be a part of the problem.
For example, one anonymous inspector is quoted to say: "A Chinese captain that was arrested last week called someone who arrived ...
CHICAGO (March 12, 2015): A surgical approach in which a surgeon removes less than a lobe of the liver in a patient undergoing an operation for liver cancer is associated with lower mortality and complication rates, according to new study results published online as an "article in press" in the Journal of the American College of Surgeons (JACS). The article will appear in print in the April issue of the Journal.
Historically, the most common surgical method of treatment for liver cancer was a major hepatectomy in which a lobe (hemi-liver) is removed in order to remove ...
Very low mammographic breast density worsens the prognosis of breast cancer, according to a recent study from the University of Eastern Finland. Disease free survivals as well as overall life expectancies were significantly shorter in women with very low-density breasts in comparison to women with high density breast tissue. The lower the breast tissue density, the less fibroglandular tissue there is compared to fat tissue.
In the future, these findings may prove significant for the assessment of breast cancer prognosis and treatment planning.
The study involved 270 ...
WASHINGTON, DC, March 12, 2015 -- Actresses need to be pickier than men about with whom they work if they want to survive in the movie industry, suggests a new study.
"My research indicates that women in the film industry suffer a lack of access to future career opportunities when they tend to work with people who have collaborated frequently in the past," said Mark Lutter, lead author of the study and head of the "Transnational Diffusion of Innovation" Research Group at the Max Planck Institute for the Study of Societies (MPIfG) in Germany.
Titled, "Do Women Suffer ...
WASHINGTON, D.C., March 12, 2015 - The American Educational Research Association has published a special edition of its peer-reviewed journal Educational Researcher (ER) devoted to examining value-added measures (VAM).
Since 2009, President Barack Obama's Race to the Top initiative has brought on a wave of value-added-based accountability measures, with value-added now embedded in policy in more than 30 states. AERA's journals have examined the validity and reliability of value-added measures over the past six years. This special issue of ER considers the key questions, ...
