0000-0001-9565-7985[Above image: Flying bumblebee. Mikkel Houmøller, wikimedia] As we ring in the New Year, we thought it would be fun to look back on the PLOS ONE articles that were the biggest hits in the news
For the month of March, a variety of papers caught the media’s attention, from distracting cell phone conversations, to the devastating decline in forest elephants. Here are some of the media highlights for this month:
Have you ever wondered where your hound originated from? In a paper featured this March, researchers have identified the fossil remains of the oldest domestic canine ancestor. In this study, researchers analyzed the DNA of a 33,000 year old tooth belonging to a Pleistocene dog from central Asia. In their evaluation of the fossil, they assessed its relationship to modern dogs and wolves’, concluding the tooth was more closely related to the domestic canine.
In another study, researchers at the Cleveland Clinic have found that football players might sustain long-term brain injuries without ever having a concussion. 67 players who had never suffered a concussion underwent testing over the course of a season. The testing, which included blood sampling, brain scans, cognitive and functional assessments, screened for potential brain damage among the participants. The researchers searched for S100B in the blood, an antibody linked to brain damage. This antibody was found in many of the participants, with the highest levels belonging to the players with the most hits.
Have you ever found yourself distracted when a co-worker is on a phone call? In an eye-catching paper published this month, PLOS ONE authors examined the effects on attention and memory when listening to cell phone conversations, versus two-sided conversations. The participants were assigned a task while two conversations were in progress, one on a cell phone, and another between two individuals. After the task was completed, the participants were assigned a recognition memory task and questionnaire measuring the distracting nature of the conversation. The participants who overhead the cell phone conversation measured it as much more distracting compared to the two-sided conversation.
And in a fourth study capturing the attention of many, researchers have examined the decline of forest elephants in Central Africa. The study concludes that forest elephants are being poached at increasing rates. Poaching, in addition to the human population rise and the absence of anti-poaching law enforcement, is contributing to the elephant’s population decline. The analysis revealed that 62 percent of the African forest elephants have been eliminated in the last decade due to poaching.
These four papers are just a taste of the variety of papers published this month. For more research headlines, visit our site here.
Druzhkova AS, Thalmann O, Trifonov VA, Leonard JA, Vorobieva NV, et al. (2013) Ancient DNA Analysis Affirms the Canid from Altai as a Primitive Dog. PLoS ONE 8(3): e57754. doi:10.1371/journal.pone.0057754
Marchi N, Bazarian JJ, Puvenna V, Janigro M, Ghosh C, et al. (2013) Consequences of Repeated Blood-Brain Barrier Disruption in Football Players. PLoS ONE 8(3): e56805. doi:10.1371/journal.pone.0056805
Galván VV, Vessal RS, Golley MT (2013) The Effects of Cell Phone Conversations on the Attention and Memory of Bystanders. PLoS ONE 8(3): e58579. doi:10.1371/journal.pone.0058579
Maisels F, Strindberg S, Blake S, Wittemyer G, Hart J, et al. (2013) Devastating Decline of Forest Elephants in Central Africa. PLoS ONE 8(3): e59469. doi:10.1371/journal.pone.0059469
Image: by digitalART2 on Flickr
Human activities and consumption pose constant threats to the environment and to wildlife but the scale of these threats can be hard to quantify. Accurate research to assess the status of threatened species is an essential first step to changing policies and human behavior that can ensure the survival of these species and habitats. The Convention on International Trade in Endangered Species or Wild Fauna and Flora (CITES) was organized to limit exploitation of international trade of wild animals and plants. Their latest meeting is currently underway in Bangkok, Thailand and two PLOS ONE papers provided evidence to support the enhanced protection of two threatened species – African forest elephants and oceanic whitetip sharks. These species were highlighted as facing intensified pressures that threaten their existence, calling for heightened regulations and better enforcement of these regulations to prevent their extinction.
One of these recently published papers provided data on declining populations of African forest elephants. By surveying the forests of five East African countries primarily by foot, researchers were able to estimate that African forest elephant populations have declined by a devastating 62% between 2002 and 2011. The drivers of this decline are complex but hinge on a renewed international demand for ivory, especially sought after among China’s growing middle class. The study was covered by NPR, the New York Times and TIME magazine.
Another study tracked the movements of the severely threatened oceanic whitetip shark. Protecting sharks from overfishing poses a complex challenge as demand for shark fin and other products rises. To shed some light on just how far this species travels, researchers tagged 11 oceanic whitetip sharks and tracked their movements over 1,563 days. The tagged sharks spent the majority of their time in the protected waters of the Bahamas Exclusive Economic Zone (EEZ), where longlining and commercial trade of sharks is illegal. But the sharks ventured up to 1200 miles outside of this protected zone the rest of the time(see Figure 2 on the right). The tendency of these sharks to roam far and wide into these unprotected waters demonstrates the need for international cooperation if the species are to be protected. The study was covered by the BBC, NBC and Scientific American.
Continued research to quantify the threat facing these species and others is necessary to bolster support for regulations to be enacted and enforced internationally by bodies like CITES. Be sure to check out PLOS ONE for more research on conservation efforts for sharks and the plight of elephants.
Citations: Maisels F, Strindberg S, Blake S, Wittemyer G, Hart J, et al. (2013) Devastating Decline of Forest Elephants in Central Africa. PLoS ONE 8(3): e59469. doi:10.1371/journal.pone.0059469
Howey-Jordan LA, Brooks EJ, Abercrombie DL, Jordan LKB, Brooks A, et al. (2013) Complex Movements, Philopatry and Expanded Depth Range of a Severely Threatened Pelagic Shark, the Oceanic Whitetip (Carcharhinus longimanus) in the Western North Atlantic. PLoS ONE 8(2): e56588. doi:10.1371/journal.pone.0056588
Images: Shark photo credit: Lance Jordan, Microwave Telemetry, Inc.
Elephant photo copyright: Fiona Maisels of Wildlife Conservation Society.
Ever wonder what purpose the sparse, coarse hairs covering an elephant’s skin serve? Authors from Princeton University wondered the same and recently published their findings in the paper “What Is the Use of Elephant Hair?” Body hair is typically thought of as an evolutionary advantage functioning mainly for insulation. Given that elephants typically inhabit warm climates and have a great need for heat loss due to their high body-volume to skin-surface ratio, insulation seems an unlikely explanation. We’ve all observed elephants using a variety of behavioral mechanisms to cool themselves down, (flapping their ears, bathing in dust, or spraying water and mud on themselves) but these alone are not sufficient in extreme heat conditions. It turns out that these little rough hairs are actually very important for keeping elephants cool.
From the Abstract:
The idea that low surface densities of hairs could be a heat loss mechanism is understood in engineering and has been postulated in some thermal studies of animals. However, its biological implications, both for thermoregulation as well as for the evolution of epidermal structures, have not yet been noted. Since early epidermal structures are poorly preserved in the fossil record, we study modern elephants to infer not only the heat transfer effect of present-day sparse hair, but also its potential evolutionary origins. Here we use a combination of theoretical and empirical approaches, and a range of hair densities determined from photographs, to test whether sparse hairs increase convective heat loss from elephant skin, thus serving an intentional evolutionary purpose. Our conclusion is that elephants are covered with hair that significantly enhances their thermoregulation ability by over 5% under all scenarios considered, and by up to 23% at low wind speeds where their thermoregulation needs are greatest. The broader biological significance of this finding suggests that maintaining a low-density hair cover can be evolutionary purposeful and beneficial, which is consistent with the fact that elephants have the greatest need for heat loss of any modern terrestrial animal because of their high body-volume to skin-surface ratio. Elephant hair is the first documented example in nature where increasing heat transfer due to a low hair density covering may be a desirable effect, and therefore raises the possibility of such a covering for similarly sized animals in the past. This elephant example dispels the widely-held assumption that in modern endotherms body hair functions exclusively as an insulator and could therefore be a first step to resolving the prior paradox of why hair was able to evolve in a world much warmer than our own.
And while on the topic of elephants, be sure to check out the videos accompanying the paper “Visualizing Sound Emission of Elephant Vocalizations: Evidence for Two Rumble Production Types” which capture the oral and nasal rumbles of elephants with an acoustic camera. The oral rumble of an elephant at 25 frames per second is below but you can watch the rest on our YouTube Channel here.
Citation: Myhrvold CL, Stone HA, Bou-Zeid E (2012) What Is the Use of Elephant Hair? PLoS ONE 7(10): e47018. doi:10.1371/journal.pone.0047018
Citation: Stoeger AS, Heilmann G, Zeppelzauer M, Ganswindt A, Hensman S, et al. (2012) Visualizing Sound Emission of Elephant Vocalizations: Evidence for Two Rumble Production Types. PLoS ONE 7(11): e48907. doi:10.1371/journal.pone.0048907