Whales’ synchronised swimming when endangered


This video is called Long-Finned Pilot Whale (Globicephala melas).

From Phys.org:

Pilot whales use synchronised swimming when they sense danger

November 23, 2012

An international team of scientists have observed the behaviour of various groups of cetaceans in the Strait of Gibraltar and Cape Breton in Canada belonging to the Globicephala melas species, which are also known as long-finned pilot whales. These results show that these whales use synchronised swimming when they identify the presence of an external threat.

There are 300 pilot whales inhabiting the Straight of Gibraltar. Here these cetaceans remain throughout the entire year in the water of the Mediterranean and the Atlantic. But, little is known about their social structure. Headed by the University of Aberdeen (United Kingdom) in collaboration with the Doñana Biological Station (CSIC) and Conservation, Information and Study on Cetaceans (CIRCE) group, the study analysed the patterns of association between individuals within this whale community. The aim was to provide a long-term vision of their social system. “The important point is that we compared two different populations: one inhabiting the Strait of Gibraltar which is exposed to predators (boats in this case) and another with an ecotype where there are not so many boats (Cape Breton in Canada). The pilot whales are social species and we were interested in seeing how mothers teach their young, for example. We observed that they use synchronised swimming when in danger,” as explained to SINC Renaud de Stephanis, researcher of the Biological Station of Doñana and coauthor of the study published in the journal Behavioural Processes. Between 1999 and 2006 the scientists gathered samples in an area of 23,004 km in the Strait of Gibraltar and took 4,887 images of the dorsal fins of whales to compare them with those in Canada.

“They swim in complete synchrony both in the Strait of Gibraltar and Canada. When sea traffic or whale watching vessels are nearby, the whole group collectively reacts to such external stimuli. When we arrived at the watching area they were swimming at their normal rhythm but after 10 or 15 minutes near to them, the mothers and their young began to swim in a synchronised manner in alert position. This is a sign of affiliation to the group,” adds the expert. According to the researcher, these cetaceans also have a social structure formed by permanent partnerships. This means that they spend their life with the same whales and they do not interchange between different groups, as in the case of bottlenose dolphins. Thanks to the study we now know that the presence of vessels also disturbs diving behaviour. “As such, when we began observing the whales up close, they tended to spend quite some time on the surface. However, the longer we spent nearby, the longer they stayed under water. This behavioural change could affect their energy levels, since they then have to make more of an effort to protect themselves and their young. In turn this limits hunting time, which means that they cannot feed their young properly,” concludes the researcher.

More information: Valeria Senigaglia, Renaud de Stephanis, Phillippe Verborgh, David Lusseau. “The role of synchronized swimming as affiliative and anti-predatory behavior in long-finned pilot whalesBehavioural Processes 91 (2012) 8-14.

Neanderthals, raptors, and ravens


This video is called Evolution – from ape man to Neanderthal – BBC science.

From PLOS ONE:

Birds of a Feather: Neanderthal Exploitation of Raptors and Corvids

The hypothesis that Neanderthals exploited birds for the use of their feathers or claws as personal ornaments in symbolic behaviour is revolutionary as it assigns unprecedented cognitive abilities to these hominins. This inference, however, is based on modest faunal samples and thus may not represent a regular or systematic behaviour.

Here we address this issue by looking for evidence of such behaviour across a large temporal and geographical framework. Our analyses try to answer four main questions: 1) does a Neanderthal to raptor-corvid connection exist at a large scale, thus avoiding associations that might be regarded as local in space or time?; 2) did Middle (associated with Neanderthals) and Upper Palaeolithic (associated with modern humans) sites contain a greater range of these species than Late Pleistocene paleontological sites?; 3) is there a taphonomic association between Neanderthals and corvids-raptors at Middle Palaeolithic sites on Gibraltar, specifically Gorham’s, Vanguard and Ibex Caves? and; 4) was the extraction of wing feathers a local phenomenon exclusive to the Neanderthals at these sites or was it a geographically wider phenomenon?.

We compiled a database of 1699 Pleistocene Palearctic sites based on fossil bird sites. We also compiled a taphonomical database from the Middle Palaeolithic assemblages of Gibraltar. We establish a clear, previously unknown and widespread, association between Neanderthals, raptors and corvids. We show that the association involved the direct intervention of Neanderthals on the bones of these birds, which we interpret as evidence of extraction of large flight feathers.

The large number of bones, the variety of species processed and the different temporal periods when the behaviour is observed, indicate that this was a systematic, geographically and temporally broad, activity that the Neanderthals undertook. Our results, providing clear evidence that Neanderthal cognitive capacities were comparable to those of Modern Humans, constitute a major advance in the study of human evolution.

See also here.

“Anatomically modern humans” (AMH), or the first subspecies which bore the closest resemblance to modern humans, lived in Africa approximately 200,000 years ago (the exact time frame is a point of contention for most archaelogists, but we’ll stick with this one). AMH inhabited a relatively small region of Africa until somewhere between 60,000 and 80,000 years ago, when our ancestors suddenly became restless and began to venture out into surrounding areas, eventually reaching Europe and Asia 40,000 years ago. The rest, as they say, is history: here.

The melting pot of early human history has just been given a good stir. The largest study of genetic variance across present-day populations in southern Africa suggests that there is no single place in Africa from which all modern humans emerged. Instead, our species is the result of mixing between numerous early human populations across a vast area: here.

Are Neanderthals Human? Here.