Human ancestors, tree climbing, other hand use


This 25 August 2019 video says about itself:

Australopithecines were our earliest ancestors, and even though they existed millions of years ago, they shared numerous characteristics that would later be present in us and were truly remarkable animals. I hope you enjoy!

From the University of Kent in England:

Dual hand use in early human relative

May 18, 2020

Research by anthropologists at the University of Kent has identified hand use behaviour in fossil human relatives that is consistent with modern humans.

The human lineage can be defined by a transition in hand use. Early human ancestors used their hands to move around in the trees, like living primates do today, whereas modern human hands have evolved to primarily perform precision grips.

However, new research led by Dr Christopher Dunmore, Dr Matthew Skinner and Professor Tracy Kivell from Kent’s School of Anthropology and Conservation has revealed that the hand of an ancient human relative was used for both human-like manipulation as well as climbing.

Their discovery came from analysing and comparing the internal bony structures of fossil knuckle and thumb joints from the hands of several fossil species from South Africa, eastern Africa and Europe. These included: Australopithecus sediba, Australopithecus africanus, Australopithecus afarensis, Homo neanderthalensis and Homo sapiens dated between 12 thousand and three million years old.

The knuckles at the base of Australopithecus sediba’s fingers were found to have an internal trabecular structure consistent with branch grasping, but that of their thumb joints is consistent with human-like manipulation. This unique combination is different to that found in the other Australopithecus species studied and provides direct evidence that ape-like features of this species were actually used, probably during climbing. Furthermore, it supports the idea that the transition to walking on two legs was gradual in this late surviving member of the Australopithecus genus.

Dr Dunmore said: ‘Internal bone structures are shaped by frequent behaviours during life. Therefore, our findings can support further research into the internal structure of hands in relation to stone tool use and production. This approach may also be used to investigate how other fossil hominin species moved around and to what degree climbing might have remained an important part of their lifestyle.’

Professor Kivell said: ‘The internal bone structure can reveal hidden evidence that gives us insight into how our fossil human relatives behaved. We were really excited to see this particular hand-use pattern in Australopithecus sediba as it was so different from other australopiths. The fossil record is revealing more and more diversity in the ways our ancestors moved around, and interacted with, their environments — the human evolutionary story is even more complex and interesting than we previously thought.’

Extinct humans Homo naledi, video


This 21 May 2020 video from Britain says about itself:

Our incredible origins: The astonishing tale of Homo naledi

Lee Berger helped unearth stunning fossils of ancient human relatives in Africa. He explains why we need to rewrite our family tree.

All primates in the world, video


This 6 May 2020 video says about itself:

The First Person To See ALL 79 Major Groups Of Primates In The Wild | Primates | BBC Earth

It’s taken primatologist Russ Mittermeier 49 years to become the first person to see every major group of primate in the wild, but he’s hoping he won’t be the only one. This is the moment he spots the final one, number 79, the kipunji.

Aye-aye lemurs of Madagascar


This 2019 video says about itself:

Aye aye (Daubentonia madagascariensis) – the bizarre lemur, the demon of the night from Madagascar

Aye-aye is one of the most bizarre mammals. It is the largest nocturnal primate in the world. Local people on Madagascar greatly fear this animal and kill it if they can. They believe that aye-aye is a bad spirit and they will die if it appears in the village.

In fact, it is specialized in eating grubs, which it gets our of the holes in the wood by its long middle finger. It taps on the wood before and detects the grub with its huge ears. Aye-aye has always growing incisors which enable it to bite to the wood. Apart from insects, it eats also fruits and seeds and that is why it comes to the plantations. Nobody knows how many aye-ayes are left in the forest of Madagascar.

Madagascar ring-tail lemurs´ love life, new research


This 2018 video is called For Ring-Tailed Lemurs, the Ladies Rule | Wild Love.

From ScienceDaily:

Male ring-tail lemurs exude fruity-smelling perfume from their wrists to attract mates

April 16, 2020

Humans aren’t the only primates who like smelling nice for their dates. In the journal Current Biology on April 16, scientists report that male ring-tailed lemurs (Lemur catta) become more attractive to females by secreting a fruity and floral aroma from their wrists. Using detailed chemical analysis, the researchers identified three compounds responsible for this sweet scent, marking the first time that pheromones have been identified in a primate.

“During the yearly breeding season, male lemurs rub the glands on their wrists against their fluffy tails and then wave them at females in a behavior called ‘stink flirting'”, says senior author Kazushige Touhara, professor and biochemist at the University of Tokyo.

Ring-tailed lemurs have well-developed scent glands on their shoulders and wrists. These glands are typically used to designate social rank, territory, and reproductive status. However, behavioral observations show they also use their scent glands to catch the attention of females. “Since only ring-tailed lemurs have these wrist glands and exhibit ‘stink flirting’ behavior, we reasoned that specific odorants for sexual communication must be involved,” Touhara says.

At the Japanese Monkey Center (JMC) in Aichi and The Research Institute of Evolutionary Biology in Tokyo, Japan, Touhara and his team tracked the behavior of a conspiracy of ring-tailed lemurs. They observed that female lemurs sniffed the scent markings left by males more often and for longer periods of time during the breeding season — when females are sexually receptive. Furthermore, when researchers isolated the primate perfume from four males and presented it to females individually, they found that females sniffed the fruity-smelling odor for roughly twice as long as the bitter-smelling gland secretions produced off-season.

“Females sniff the floral and fruity scent for a few more seconds than the controls and occasionally even lick it. Although this sounds like a very short time, it’s enough to recognize or evoke curiosities in the male,” says Touhara.

Using gas chromatography-mass spectrometry analysis on the of the wrist-gland secretions produced during breeding and non-breeding seasons, Touhara determined the major chemical components making up the male scents. Three aldehyde compounds — dodecanal, 12-methyltridecanal, and tetradecanal — were present in both odors but showed substantially higher concentrations during the breeding season. Moreover, when the compounds were individually presented to females in the JMC enclosure, researchers found that only the mixture of all three had a significant ability to hold a female’s attention.

“All three compounds have been suggested to be involved in the recognition of newborn sheep by their mothers, and tetradecanal is known as a sex pheromone in some insect species. Although this is the first time 12-methyltridecanal has been identified in primate species, all three aldehydes appear to be used as communication tools widely throughout the animal kingdom,” says Touhara.

Young, sexually mature males naturally produce more of these compounds than their senior male counterparts — most likely because aged males produce less testosterone. Furthermore, scientists have observed that females past their reproductive prime are altogether unimpressed by the fruity-smelling odors males exude. These findings suggest that the three compounds are, indeed, pheromones, but more work is required to determine whether they directly influence sexual behavior. “While we have not examined behavioral changes after the sniff in detail, this is an area for future work to determine whether these pheromones impact mating success.”

Apes’ ears and human evolution


This 2014 video says about itself:

Our ears are much more sensitive than most reptiles’, due to the tiniest bones in the human body. But where did these bones come from? Evolutionary biologists Karen Sears and Neil Shubin show us evidence of their connection to the bones of ancient reptilian jaws.

From eLife:

Apes’ inner ears could hide clues to evolutionary history of hominoids

New findings highlight the potential of the inner ear for reconstructing the early branches of our family tree

March 3, 2020

Studying the inner ear of apes and humans could uncover new information on our species’ evolutionary relationships, suggests a new study published today in eLife.

Humans, gorillas, chimpanzees, orangutans and gibbons all belong to a group known as the hominoids. This ‘superfamily’ also includes the immediate ancestors and close relatives of these species, but in many instances, the evolutionary relationships between these extinct ape species remain controversial. The new findings suggest that looking at the structure (or morphology) of the inner ears across hominoids as a whole could go some way to resolving this.

“Reconstructing the evolutionary history of apes and humans and determining the morphology of the last common ancestor from which they evolved are challenging tasks,” explains lead author Alessandro Urciuoli, a researcher at the Institut Català de Paleontologia Miquel Crusafont (ICP) in Barcelona, Spain. “While DNA can help evolutionary biologists work out how living species are related to one another, fossils are typically the principal source of information for extinct species, although they must be used with caution.”

The bony cavity that houses the inner ear, which is involved in balance and hearing and is fairly common in the fossil record, has proven useful for tracing the evolution of certain groups of mammals. But until now, no studies have explored whether this structure could provide insights into the evolutionary relatedness among living and extinct hominoids.

To address this, Urciuoli and his team used a 3D imaging technique to capture the complex shapes of the inner ear cavities of 27 species of monkeys and apes, including humans and the extinct ape Oreopithecus and fossil hominin Australopithecus. Their results confirmed that the shape of these structures most closely reflected the evolutionary relationships between the species and not, for example, how the animals moved.

The team next identified features of these bony chambers that were shared among several hominoid groups, and estimated how the inner ears of these groups’ ancestors might have looked. Their findings for Australopithecus were consistent with this species being the most closely related to modern humans than other apes, while those for Oreopithecus supported the view that this was a much older species of ape related in some respects with other apes still alive today.

“Our work provides a testable hypothesis about inner ear evolution in apes and humans that should be subjected to further scrutiny based on the analysis of additional fossils, particularly for great apes that existed during the Miocene,” says senior author David Alba, Director of the ICP. The Miocene period, which extends from about 23 to five million years ago, is when the evolutionary path to hominoids became distinct.

Urciuoli adds that, in years to come, disentangling the kinship relationships between Miocene apes will be essential for improving our understanding of the evolution of hominoids, including humans and our closest living relatives, the chimpanzee and bonobo.

Kenyan primate seen again after twenty years


This 18 February 2020 video from Kenya is called Elusive African primate captured on camera for the first time in 20 YEARS.

From the University of Helsinki in Finland, 18 February 2020:

Good news from the Kenyan Taita Hills: the Taita mountain dwarf galago still survives. This was confirmed by researchers working at the University of Helsinki Taita Research Station.

The tiny nocturnal prosimian, weighing only 100-180 grams, was first reported in 2002, but no sightings had been made since.