Fasting for Lent Forces Hyenas to Change Diet

Many Christians give up certain foods for Lent, however ecologists have discovered these changes in human diet have a dramatic impact on the diet of wild animals. In Ethiopia, members of the Orthodox Tewahedo Church stop eating meat and dairy products during a 55-day fast before Easter. As a result, spotted hyenas too change their eating habits -- from scavenging waste from butchers and households to hunting -- new research in the British Ecological Society's Journal of Animal Ecology has found.
 
Spotted hyenas are supremely adaptable mammals, capable both of adapting to habitats with dense human populations and to eating whatever food is available. While they are efficient hunters, they are also opportunistic scavengers, eating everything from birds, mammals, fish and reptiles to garbage, cooked porridge and dung. And they have digestive systems to match, says Gidey Yirga from Mekelle University.
"Hyenas can eat almost any organic matter, even putrid carrion and anthrax-infected carcasses. They are capable of eating and digesting all parts of their prey except hair and hooves. Bones are digested so completely that only the inorganic components are excreted in the hyena's droppings," he explains.
Working at three sites around Mekelle in northern Ethiopia, Yirga collected all hyena droppings from each 1 hectare site on three occasions on the first and last days of the 55-day Abye Tsome (Lent) fast, and then again 55 days after the fast ended -- a total of 553 droppings.
To find out what the hyenas had been eating before, during and after Lent, he compared hairs found in the hyenas' droppings with a reference collection of hair from other animals found in the region.
The results showed that when humans stop buying, eating and discarding animal products the hyenas' eating habits change significantly: before Lent, 14.8% of hyena droppings contained donkey hairs, during Lent this increased to 33.1%, falling again to 22.2% once the fast was over.
According to Yirga: "Our study shows a remarkable change in the hyenas' diet -- we found that hyenas around Mekelle mainly scavenge waste from butchers and households but during fasting donkeys provided an alternative food source."
By providing this unique insight into the effect of changes in human diet on local hyenas, the results illustrate that hyenas are highly adaptable and opportunistic scavengers and hunters. They also have implications for those managing the conflict that can arise when large carnivores use anthropogenic food sources.
"Understanding details of the foraging behaviour of carnivores in an anthropogenic environment can help reveal specific causes of conflict, leading to better strategies for reducing availability of anthropogenic food and preventing conflict," Yirga concludes.

Feeding babies on demand may improve IQ

Ba­bies who are fed when­ev­er they want may lat­er per­form bet­ter in school than those who were fed on a sched­ule, new re­search sug­gests.

The find­ing is based on the re­sults of in­tel­li­gence tests and school-based stand­ard­ized tests car­ried out be­tween the ages of five and 14. The IQ scores of eight-year-old chil­dren who had been demand-fed as ba­bies were four to five points high­er than the scores of sched­ule-fed chil­dren, the stu­dy found. IQ tests are a meas­ure of in­tel­li­gence de­signed to ex­press the dif­fer­ence be­tween a per­son’s in­tel­li­gence and the av­er­age in­tel­li­gence for their age group, roughly as a per­cent­age.

The find­ings are pub­lished in the Eu­ro­pe­an Jour­nal of Pub­lic Health.

The study was car­ried out by re­search­ers at the In­sti­tute for So­cial and Eco­nom­ic Re­search at the Uni­vers­ity of Es­sex, U.K., and at the Uni­vers­ity of Ox­ford. But the re­search­ers urged cau­tion in in­ter­pret­ing the find­ings.

“We must be very cau­tious about claim­ing a caus­al link be­tween feed­ing pat­terns and IQ. We can­not de­fin­i­tively say why these dif­fer­ences oc­cur, al­though we do have a range of hy­pothe­ses. This is the first study to ex­plore this ar­ea and more re­search is needed to un­der­stand the pro­cesses in­volved,” said Ma­ria Ia­covou, who led the re­search from the Uni­vers­ity of Es­sex.

Tak­ing in­to ac­count a wide range of back­ground fac­tors that in­clude par­ents’ educa­t­ional lev­el, family in­come, the child’s sex and age, ma­ter­nal health and par­ent­ing styles, the re­search found that demand-feed­ing is as­so­ci­at­ed with high­er IQ scores at age eight, and this dif­fer­ence is al­so ev­i­dent in the re­sults of stand­ard­ized tests at ages five, sev­en, 11 and 14. The study found that sched­uled feed­ing times did have ben­e­fits for the moth­ers, how­ev­er, who re­ported feel­ings of con­fi­dence and high lev­els of well-be­ing.

“The dif­fer­ence be­tween sched­ule and demand-fed chil­dren is found both in breast­fed and in bottle-fed ba­bies,” said Ia­covou.

“The dif­fer­ence in IQ lev­els of around four to five points, though sta­tis­tic­ally highly sig­nif­i­cant, would not make a child at the bot­tom of the class move to the top, but it would be no­tice­a­ble. To give a sense of the kind of dif­fer­ence that four or five high­er IQ points might make, in a class of 30 chil­dren, for ex­am­ple, a child who is right in the mid­dle of the class, ranked at 15th, might be, with an im­prove­ment of four or five IQ points, ranked higher, at about 11th or 12th in the class.”

The chil­dren of moth­ers who had tried but failed to feed to a sched­ule were found to have si­m­i­lar test scores as demand-fed ba­bies, Ia­covou said, which is no­ta­ble be­cause they would be ex­pected to do worse based on their moth­ers’ typ­i­cal de­mograph­ics. “It seems that it is ac­tu­ally hav­ing been fed to a sched­ule, rath­er than hav­ing the type of moth­er who at­tempted to feed to a sched­ule (suc­cess­fully or not) which makes the dif­fer­ence,” she said.

Link between fast food, depression “confirmed”

A new study sup­ports past re­search ty­ing fast food con­sump­tion to a great­er risk of de­pres­sion.
 Pub­lished in the re­search jour­nal Pub­lic Health Nu­tri­tion, the re­sults in­di­cate that fre­quent con­sumers of fast food are 51 per­cent more likely to de­vel­op de­pres­sion than those who eat lit­tle or none of it. And “the more fast food you con­sume, the great­er the risk of de­pres­sion,” said Al­mu­dena Sán­chez-Villegas of the Uni­vers­ity of Las Pal­mas de Gran Ca­naria in Spain, the stu­dy’s lead au­thor.

A new study sup­ports past re­search show­ing that eat­ing fast food is linked to a great­er risk of de­pres­sion. (Image © Joey)

The study in­clud­ed 8,964 par­ti­ci­pants that had nev­er been di­ag­nosed with de­pres­sion or tak­en an­ti­de­pres­sants. They were as­sessed for an av­er­age of six months; dur­ing that time, 493 were di­ag­nosed with de­pres­sion or started to take an­ti­de­pres­sants.

The re­search al­so found that par­ti­ci­pants who ate the most fast food and com­mer­cially baked goods were more likely to be sin­gle, less ac­tive and have poor di­e­tary habits, which in­clud­ed eat­ing less fruit, nuts, fish, veg­eta­bles and ol­ive oil. Smok­ing and work­ing more than 45 hours per week were oth­er prev­a­lent char­ac­ter­is­tics.

The da­ta was found to sup­port re­search pub­lished last year in the jour­nal PLoS One, which recorded 657 new cases of de­pres­sion out of 12,059 peo­ple an­a­lyzed over more than six months. A 42 per­cent in­crease in de­pres­sion risk as­so­ci­at­ed with fast food was found.

“Although more stud­ies are nec­es­sary, the in­take of this type of food should be con­trolled,” Sánchez-Villegas pro­posed. He cit­ed its ef­fects for both men­tal and phys­i­cal health, in­clud­ing its es­tab­lished ten­den­cy to pro­mote obes­ity and car­di­o­vas­cu­lar dis­ease.

De­pres­sion af­fects an es­ti­mat­ed 121 mil­lion peo­ple world­wide. Pre­vi­ous stud­ies sug­gest that cer­tain nu­tri­ents may help pre­vent de­pres­sion. These in­clude group B vi­ta­mins, omega-3 fat­ty acids and ol­ive oil, as well as a healthy “Mediterranean”-type di­et more gen­er­al­ly.

Carbon Nanotubes Can Double Growth of Cell Cultures

A dose of carbon nanotubes more than doubles the growth rate of plant cell cultures -- workhorses in the production of everything from lifesaving medications to sweeteners to dyes and perfumes -- researchers are reporting.
  
Their study, the first to show that carbon nanotubes boost plant cell division and growth, appears in the journal ACS Nano.
Mariya V. Khodakovskaya and colleagues explain that their previous research demonstrated that so-called multiwalled carbon nanotubes (MWCNTs) can penetrate through the thick coatings on seeds, stimulate germination of the seeds and stimulate the growth of certain plants. MWCNTs are wisps of pure carbon so small that thousands would fit on the period at the end of this sentence. Those discoveries "have the potential to transform agricultural practices in the near future and to provide solutions to some of the most serious problems related to plant growth and development," the scientists said.
Their new research focused on how MWCNTs affect the growth of model tobacco plant cell cultures. Plant cells of many plant species, grown in large industrial vats, find extensive use in producing medical and commercial products and plants for agriculture. The scientists found that tiny amounts of MWCNTs ramped up the activity of genes involved in cell growth. MWCNTs also seem to work by activation of channels that transport water into cells, helping cells divide and grow faster.
The authors acknowledge funding from the EPSCoR Center for Plant-Powered Production and the Arkansas Science & Technology Authority.