Zebra stripes help against flies

This 20 February 2019 video says about itself:

How Do Zebra Stripes Stop Biting Flies?

Scientists learned in recent years why zebras have black and white stripes – to avoid biting flies. But, what is it about stripes that so disrupts a biting fly’s ability to land on a zebra and suck its blood? UC Davis Professor Tim Caro led a series of unique experiments for this study to better understand how stripes manipulate the behavior of biting flies as they attempt to come in for a landing on a zebra.

From PLOS:

Zebra stripes are not good landing strips

Stripes reduce controlled landing by biting flies, supporting the leading hypothesis of their utility

February 20, 2019

The stripes of a zebra deter horse flies from landing on them, according to a new study published February 20, 2019 in the open-access journal PLOS One by Tim Caro of the University of California Davis, Martin How of the University of Bristol, and colleagues.

Zebra stripes have been posited to provide camouflage, visually confuse predators, signal to other zebras, or help control heat gain, but none of these hypotheses have withstood rigorous experimentation. An alternative, that stripes somehow reduce the likelihood of being bitten by predatory flies, has gained adherents, but the mechanism has been unclear.

In the new study, the authors compared behavior of horse flies as they attempted to prey on zebras and uniformly colored horses held in similar enclosures. Flies circled and touched horses and zebras at similar rates, but actually landed on zebras less than one-quarter as often. When horses wore a striped, black or white coat, flies landed far less often on the striped coat, but just as often on the uncovered head. The authors found that while flies decelerated prior to landing on horses, they approached zebras at a faster clip and failed to slow down as they closed the distance, often bumping into the zebra before flying away again.

Additionally, zebras were at greater pains to keep flies off through tail swishing and running away.

Taken together, these results indicate that stripes do not deter flies from approaching zebras, but do prevent effective landing, and thus, reduce the number of flies successfully feeding. This finding provides further support for the hypothesis that the evolutionary benefit of zebra stripes is to reduce biting by predatory flies.

The authors add: “Zebra stripes are now believed to have evolved to thwart attack by biting flies. We observed and filmed the behaviour of horse flies near captive zebras and horses and found that flies failed to decelerate close to stripes preventing controlled landings. Combined with zebras’ anti-parasite behavior, few flies landed successfully or probed their hosts for blood.”


‘Belgian Africa Museum still neocolonialist’

This 9 December 2018 video says about itself:

Belgium’s Africa museum reopened its doors in the Tervuren Palace outside Brussels on Sunday, after five years of restoration works. The reopening has fueled a debate on whether African artefacts should be given back to their countries of origin, as President of the Democratic Republic of Congo Joseph Kabila called for the repatriation of the items. …

The museum was founded by King Leopold II to house items collected in the Congo Free State during Belgian rule, including beheaded skulls of tribal chiefs and stuffed animals slaughtered by hunters.

Translated from Dutch NOS TV today:

United Nations criticize ‘racist images’ in the reopened Belgian Africamuseum

An anti-racism working group of the United Nations has criticized the Africamuseum in Tervuren, near Brussels. The museum was recently reopened after a thorough renovation, which was decided after a public debate about the glorification of colonization in the museum.

The museum removed statues of King Leopold II and placed signs with additional explanations at controversial texts. However, the changes do not go far enough for the UN.

Belgian Congo was a colony of Belgium between 1908 and 1960. Since 1885, the country had already been a private colony of the Belgian king Leopold II. The country is now called Congo-Kinshasa.

The colonization period is a black page in Belgian history. Under the Belgian administration, millions of people died and the local population was exploited.

The Africa experts working group visited Belgium last week and presented its conclusions in a press release yesterday. According to the experts, the Africamuseum is the most visible post-colonial expression in Belgium. The museum must remove all “racist and offensive” images, they think.

“The Working Group is of the view that the reorganization of the museum has not gone far enough”, says the report. “The reorganization falls short of its goal of providing adequate context and critical analysis. The Working Group notes the importance of removing all colonial propaganda and accurately presenting the atrocities of Belgium’s colonial past.”

The working group also does not like the many statues of Leopold II and his colonial army in the Belgian street scene. The contributions of people with African roots to Belgian society must become more visible, according to the UN group. They also demand that the Belgian government apologize for this period in Belgian history.

The UN working group falls under the office of the High Commissioner for Human Rights (OHCHR). In 2013, the working group did research on Zwarte Piet [blackface Saint Nicholas holiday character] in the Netherlands. Two years later the UN advised the Dutch government to change the tradition.

In Belgian media, Minister of Development Cooperation Alexander De Croo responded surprisedly to the report.

In this 8 December 2018 Dutch language video, Kenyan Belgian Stella Nyanchama Okemwa visits the reopened museum. She notes there is a plaque in the museum commemorating Belgians who died in Congo, but that nothing there commemorates the very many more Congolese who died violent deaths because of colonialism. She also notes sculpture, depicting Africans as small children next to big Belgian Catholic missionaries.

Warthogs, mongooses and insects

This 5 February 2019 video, recorded in Africa, says about itself:

The Smart Way Warthogs Keep Insects at Bay

Warthogs love a good roll in the mud – known as ‘wallowing’ – which keeps them cool. But to protect themselves from insects, warthogs turn to another creature to help out: the mongoose.

Hippos in Africa, video

This 4 January 2019 video from Africa says about itself:

Getting Close To Hippos with A Spy Cam | Earth’s Great Rivers | Earth Unplugged

In this exclusive Behind The Scenes, the film crew manages to get some amazing hippo shots thanks to some unusual filming techniques.

Africa cradle of humankind, where in Africa?

This 15 November 2016 video says about itself:

Ain El Hanech (North Eastern Algeria)

The Algerian famous archeological site. Although there is uncertainty about some factors, Aïn el-Hanech (in Algeria) is the site of one of the earliest traces of hominid occupation.

From the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) in Spain:

The whole of Africa was the cradle of humankind

Oldest stone artifacts and cutmarked bones in North Africa contemporary with archaeological materials in East Africa

November 29, 2018

A team of scientists led by Mohamed Sahnouni, archaeologist at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), has just published a paper in the journal Science which breaks with the paradigm that the cradle of humankind lies in East Africa, based on the archaeological remains found at sites in the region of Ain Hanech (Algeria), the oldest currently known in the north of Africa.

For a long time, East Africa has been considered the place of origin of the earliest hominins and lithic technology, because up to now, very little was known about the first hominin occupation and activities in the north of the continent. Two decades of field and laboratory research directed by Dr. Sahnouni have shown that ancestral hominins actually made stone tools in North Africa that are near contemporary with the earliest known stone tools in East Africa dated to 2.6 million years.

These are stone artifacts and animal bones bearing marks of cutting by stone tools, with an estimated chronology of 2.4 and 1.9 million years, respectively, found at two levels at the sites of Ain Boucherit (within the Ain Hanech study area), which were dated using Paleomagnetism, Electron Spin Resonance (ESR), and the Biochronology of large mammals excavated together with the archaeological materials.

Fossils of animals such as pigs, horses and elephants, from very ancient sites, have been used by the paleontologist Jan van der Made, of the Museo Nacional de Ciencias Naturales in Madrid, to corroborate the ages yielded by Paleomagnetism, obtained by the CENIEH geochronologist Josep Parés, and ESR, found by Mathieu Duval, of Griffith University.

Oldowan technology

The artifacts of Ain Boucherit were manufactured of locally available limestone and flint and include faces worked into choppers, polyhedra and subspheroids, as well as sharp-edged cutting tools used to process animal carcasses. These artifacts are typical of the Oldowan stone technology known from 2.6-1.9 million-year-old sites in East Africa, although those from Ain Boucherit show subtle variations.

“The lithic industry of Ain Boucherit, which is technologically similar to that of Gona and Olduvai, shows that our ancestors ventured into all corners of Africa, not just East Africa. The evidence from Algeria changes the earlier view that East Africa was the cradle of Humankind. Actually, the whole of Africa was the cradle of humankind,” states Sahnouni, leader of the Ain Hanech project.

Not mere scavengers

Ain Boucherit is one of the few archaeological sites in Africa which has provided evidence of bones with associated marks of cutting and percussion in situ with stone tools, which shows unmistakably that these ancestral hominins exploited meat and marrow from animals of all sizes and skeletal parts, which implied skinning, evisceration and defleshing of upper and intermediate extremities.

Isabel Cáceres, taphonomist at the IPHES, has commented that “the effective use of sharp-edged tools at Ain Boucherit suggests that our ancestors were not mere scavengers. It is not clear at this moment whether they hunted, but the evidence clearly shows that they were successfully competing with carnivores and enjoyed first access to animal carcasses.”

The tool-makers

At this moment, the most important question is who made the stone tools discovered in Algeria. Hominin remains have still not been found in North Africa which are contemporary with the earliest stone artifacts. As a matter of fact, nor have any hominins yet been documented in direct association with the first stone tools known from East Africa.

Nevertheless, a recent discovery in Ethiopia has shown the presence of early Homo dated to 2.8 million years, most likely the best candidate also for the materials from East and North Africa.

Scientists thought for a long time that the hominins and their material culture originated in the Great Rift Valley in East Africa. Surprisingly, the earliest known hominin, dated to 7.0 million years, and the 3.3 million years Australopithecus bahrelghazali, have been discovered in Chad, in the Sahara, 3000 km from the rift valleys in the east of Africa.

As Sileshi Semaw, scientist at the CENIEH and a co-author of this paper, explains that the hominins contemporary with Lucy (3.2 million years), were probably roamed over the Sahara, and their descendants might have been responsible for leaving these archaeological puzzles now discovered in Algeria, that are near contemporaries of those of East Africa.

“Future research will focus on searching for human fossils in the nearby Miocene and Plio-Pleistocene deposits, looking for the tool-makers and even older stone tools,” concludes Sahnouni.