What mom doesn't get stressed out every now and then? Stress is usually considered a bad thing, but new research suggests that mom's stress can actually give her future offspring certain physical advantages, at least in the case of one bird species.
A few years ago, experiments on barn swallows demonstrated that when ovulating females were exposed to models of predators, their eggs had higher levels of the stress hormone corticosterone, which resulted in reduced hatchability and smaller fledglings. A study published this month in linkurl:Functional Ecology;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2011.01834.x/abstract shows that nesting great tits exposed to stuffed models and audio calls of their predators also have smaller offspring, but the chicks' wings actually grow faster and longer, resulting in wings about 1.8 millimetres longer than the offspring of less stressed mothers -- a difference that might make the birds better at avoiding predators in flight, linkurl:according to Nature.;http://www.nature.com/news/2011/110325/full/news.2011.187.html
Monkeys bathe in urine to attract mates
Scientists may have finally found an explanation for the strange tendency of tufted capuchin monkeys to rub their own urine all over themselves -- it's all about the ladies. New research, published last month in the linkurl:American Journal of Primatology,;http://onlinelibrary.wiley.com/doi/10.1002/ajp.20931/abstract shows that female brains are excited by the smell of sexually mature males' urine, suggesting males perform "urine washes" to signal their availability to females.
Tufted capuchins aren't the only monkeys to partake in such bizarre behavior -- mantled howler monkeys, squirrel monkeys and other capuchins species have all been observed urinating into their hands and rubbing it into their fur. Scientists previously guess that the behavior was meant to help regulated body temperature or to mark themselves for individual identification by their comrades. But the new study found that "female capuchin monkey brains react differently to the urine of adult males than to urine of juvenile males," study author Kimberley Phillips, a primatologist at Trinity University in San Antonio, Texas, linkurl:told the BBC.;http://news.bbc.co.uk/earth/hi/earth_news/newsid_9404000/9404757.stm linkurl:(Hat tip to Huffington Post);http://www.huffingtonpost.com/2011/03/01/why-monkeys-wash-in-urine_n_829388.html
Elephants, smart and cooperative
Elephant herds would do right to follow their elders. According to a recent study published in linkurl:Proceedings of the Royal Society of London B,;http://rspb.royalsocietypublishing.org/content/early/2011/03/10/rspb.2011.0168 older elephant matriarchs are better at assessing threats than younger animals. Specifically, female elephants over the age of 60 appeared to better determine the level of danger posed by recordings of lions, reacting more defensively to the roars of male cats, which can be more deadly than lionesses, linkurl:according to Wired Science.;http://www.wired.com/wiredscience/2011/03/elephant-memory-leadership/ Although they rarely hunt, just one male lion can bring down an elephant calf.
Elephants were also recently shown to be impressively cooperative, helping each other obtain food by pulling on two ends of the same rope. The study, published earlier this month in the linkurl:Proceedings of the National Academy of Sciences,;http://www.pnas.org/content/early/2011/03/02/1101765108.abstract demonstrates that elephants also timed their pulls, waiting for their partners to get a hold of the rope before tugging together.
Finding the shark spa
Thresher sharks in waters off the the Philippines keep fresh by routinely visiting a sea mount home to cleaner fish that rid them of parasites and dead skin. "They pose, lowering their tails to make themselves more attractive to the cleaners," Simon Oliver from Bangor University in the UK, who filmed the sharks and published his findings in linkurl:PLoS ONE,;http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014755 told the linkurl:BBC.;http://news.bbc.co.uk/earth/hi/earth_news/newsid_9427000/9427886.stm "And they systematically circle for about 45 minutes at speeds lower than one metre per second."
To find their way to the cleaning site, the sharks may use a mental map. A new study published in the linkurl:Journal of Animal Ecology;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2011.01815.x/full that analyzed tracking data from three species of sharks suggests that tiger and thresher sharks, but not blacktip reef sharks, are capable of navigating directly to specific locations.
Here's one for the record books -- a sexual act, performed by ancient mites, preserved in a drop of tree resin for 40 million years. The discovery, reported in the March issue of the linkurl:Biological Journal of the Linnean Society,;http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8312.2010.01595.x/abstract is more than just a peek into the bedroom of an extinct insect species. It's also a glimpse at an ancient example of sex role reversal, where the female, who is clinging to her mate with her back legs, appears to be in control of the action, linkurl:according to Discovery News.;http://news.discovery.com/animals/40-million-year-old-sex-act-captured-in-amber.html
**__Related stories:__*** linkurl:Manipulative mosquito semen;http://www.the-scientist.com/news/display/58052/ [15th March 2011]*linkurl:Behavior brief;http://www.the-scientist.com/news/display/57966/ [28th January 2011]*linkurl:Behavior brief;http://www.the-scientist.com/news/display/57909/ [6th January 2011]
**__Related F1000 Evaluations:__***linkurl:Scales of orientation, directed walks and movement path structure in sharks;http://f1000.com/9002957?key=t7qwfd0qg53tb6c Y.P. Papastamatiou et al., J Anim Ecol, ePub, 2011. Evaluated by Kent Berridge, University of Michigan.*linkurl:Leadership in elephants: the adaptive value of age;http://f1000.com/9180957?key=wc30wyp1w6j6t5d K. McComb et al., Proc Biol Sci, ePub, 2011. Evaluated by Daniel Promislow, University of Georgia.