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Royal Society Open Science Nov 2023The social complexity hypothesis for the evolution of communication posits that complex social environments require greater communication complexity for individuals to...
The social complexity hypothesis for the evolution of communication posits that complex social environments require greater communication complexity for individuals to effectively manage their relationships. We examined how different socially uncertain contexts, reflecting an increased level of social complexity, relate to variation in signalling within and between two species, which display varying levels of fission-fusion dynamics (sympatric-living chimpanzees and sooty mangabeys, Taï National Park, Ivory Coast). Combined signalling may improve message efficacy, notably when involving different perception channels, thus may increase in moments of high social uncertainty. We examined the probability of individuals to emit no signal, single or multisensory or combined (complex) signals, during social approaches which resulted in non-agonistic outcomes. In both species, individuals were more likely to use more combined and multisensory signals in post-conflict approaches with an opponent than in other contexts. The clearest impact of social uncertainty on signalling complexity was observed during chimpanzee fusions, where the likelihood of using complex signals tripled relative to other contexts. Overall, chimpanzees used more multisensory signals than mangabeys. Social uncertainty may shape detected species differences in variation in signalling complexity, thereby supporting the hypothesis that social complexity, particularly associated with high fission-fusion dynamics, promotes signalling complexity.
PubMed: 38034119
DOI: 10.1098/rsos.231073 -
Scientific Reports Nov 2023The utilization of mechanical ventilation is of utmost importance in the management of individuals afflicted with severe pulmonary conditions. During periods of a...
The utilization of mechanical ventilation is of utmost importance in the management of individuals afflicted with severe pulmonary conditions. During periods of a pandemic, it becomes imperative to build ventilators that possess the capability to autonomously adapt parameters over the course of treatment. In order to fulfil this requirement, a research investigation was undertaken with the aim of forecasting the magnitude of pressure applied on the patient by the ventilator. The aforementioned forecast was derived from a comprehensive analysis of many variables, including the ventilator's characteristics and the patient's medical state. This analysis was conducted utilizing a sophisticated computational model referred to as Long Short-Term Memory (LSTM). To enhance the predictive accuracy of the LSTM model, the researchers utilized the Chimp Optimization method (ChoA) method. The integration of LSTM and ChoA led to the development of the LSTM-ChoA model, which successfully tackled the issue of hyperparameter selection for the LSTM model. The experimental results revealed that the LSTM-ChoA model exhibited superior performance compared to alternative optimization algorithms, namely whale grey wolf optimizer (GWO), optimization algorithm (WOA), and particle swarm optimization (PSO). Additionally, the LSTM-ChoA model outperformed regression models, including K-nearest neighbor (KNN) Regressor, Random and Forest (RF) Regressor, and Support Vector Machine (SVM) Regressor, in accurately predicting ventilator pressure. The findings indicate that the suggested predictive model, LSTM-ChoA, demonstrates a reduced mean square error (MSE) value. Specifically, when comparing ChoA with GWO, the MSE fell by around 14.8%. Furthermore, when comparing ChoA with PSO and WOA, the MSE decreased by approximately 60%. Additionally, the analysis of variance (ANOVA) findings revealed that the p-value for the LSTM-ChoA model was 0.000, which is less than the predetermined significance level of 0.05. This indicates that the results of the LSTM-ChoA model are statistically significant.
Topics: Humans; Animals; Ventilators, Mechanical; Algorithms; Respiration, Artificial; Random Forest; Analysis of Variance; Cetacea; Pan troglodytes
PubMed: 38017008
DOI: 10.1038/s41598-023-47837-8 -
Scientific Reports Nov 2023The anatomy of the auditory region of fossil hominins may shed light on the emergence of human spoken language. Humans differ from other great apes in several features...
The anatomy of the auditory region of fossil hominins may shed light on the emergence of human spoken language. Humans differ from other great apes in several features of the external, middle and inner ear (e.g., short external ear canal, small tympanic membrane, large oval window). However, the functional implications of these differences remain poorly understood as comparative audiometric data from great apes are scarce and conflicting. Here, we measure the sound transfer function of the external and middle ears of humans, chimpanzees and bonobos, using laser-Doppler vibrometry and finite element analysis. This sound transfer function affects auditory thresholds, which relate to speech reception thresholds in humans. Unexpectedly we find that external and middle ears of chimpanzees and bonobos transfer sound better than human ones in the frequency range of spoken language. Our results suggest that auditory thresholds of the last common ancestor of Homo and Pan were already compatible with speech reception as observed in humans. Therefore, it seems unlikely that the morphological evolution observed in the bony auditory region of fossil hominins was driven by the emergence of spoken language. Instead, the peculiar human configuration may be a by-product of morpho-functional constraints linked to brain expansion.
Topics: Animals; Humans; Pan troglodytes; Auditory Threshold; Pan paniscus; Speech; Hominidae
PubMed: 38007561
DOI: 10.1038/s41598-023-47778-2 -
Genome Biology and Evolution Nov 2023Y chromosomal ampliconic genes (YAGs) are important for male fertility, as they encode proteins functioning in spermatogenesis. The variation in copy number and...
Y chromosomal ampliconic genes (YAGs) are important for male fertility, as they encode proteins functioning in spermatogenesis. The variation in copy number and expression levels of these multicopy gene families has been studied in great apes; however, the diversity of splicing variants remains unexplored. Here, we deciphered the sequences of polyadenylated transcripts of all nine YAG families (BPY2, CDY, DAZ, HSFY, PRY, RBMY, TSPY, VCY, and XKRY) from testis samples of six great ape species (human, chimpanzee, bonobo, gorilla, Bornean orangutan, and Sumatran orangutan). To achieve this, we enriched YAG transcripts with capture probe hybridization and sequenced them with long (Pacific Biosciences) reads. Our analysis of this data set resulted in several findings. First, we observed evolutionarily conserved alternative splicing patterns for most YAG families except for BPY2 and PRY. Second, our results suggest that BPY2 transcripts and proteins originate from separate genomic regions in bonobo versus human, which is possibly facilitated by acquiring new promoters. Third, our analysis indicates that the PRY gene family, having the highest representation of noncoding transcripts, has been undergoing pseudogenization. Fourth, we have not detected signatures of selection in the five YAG families shared among great apes, even though we identified many species-specific protein-coding transcripts. Fifth, we predicted consensus disorder regions across most gene families and species, which could be used for future investigations of male infertility. Overall, our work illuminates the YAG isoform landscape and provides a genomic resource for future functional studies focusing on infertility phenotypes in humans and critically endangered great apes.
Topics: Animals; Male; Humans; Pan paniscus; Hominidae; Y Chromosome; Pan troglodytes; Protein Isoforms
PubMed: 37967251
DOI: 10.1093/gbe/evad205 -
Human Nature (Hawthorne, N.Y.) Dec 2023Honest signalling theory suggests that humans and chimpanzees can extract socially relevant information relating to personality from the faces of their conspecifics....
Honest signalling theory suggests that humans and chimpanzees can extract socially relevant information relating to personality from the faces of their conspecifics. Humans are also able to extract information from chimpanzees' faces. Here, we examine whether personality characteristics of chimpanzees, including measures of psychopathy, can be discerned based purely on facial morphology in photographs. Twenty-one chimpanzees were given naïve and expert personality ratings on the Ten Item Personality Inventory (TIPI) and the Chimpanzee Triarchic Model of Psychopathy (CHMP-Tri) before and following behavioural observations. Characteristics relating to openness, conscientiousness, extraversion, and disinhibition could be distinguished from the faces of chimpanzees. Individuals higher on disinhibition have lower scores on conscientiousness and emotional stability and higher scores on extraversion, while those higher on meanness have lower conscientiousness and agreeableness. Facial expressions are linked to personality traits present in the TIPI and CHMP-Tri models: the Relaxed Face and the Grooming Face were displayed more by chimpanzees higher on agreeableness, whereas the Compressed Lips Face was observed more in those individuals higher on boldness, and the Full Open Grin was displayed more by chimpanzees higher on extraversion but lower on emotional stability and conscientiousness. Facial expressions were also found to be associated with particular behavioural contexts, namely the Grooming Face in affiliative contexts and the Relaxed and Relaxed Open Mouth Faces in neutral contexts. Dominant chimpanzees display higher levels of boldness and more Compressed Lips Faces, Relaxed Open Mouth Faces, and Grooming Faces than subordinate individuals. These findings support and extend evidence for an honest signalling system and a personality structure shared between humans and chimpanzees. Future research could further explore how personality is conveyed through the face, perhaps through more than just singular aspects of character, and maybe reflecting what chimpanzees themselves are able to do.
Topics: Animals; Humans; Pan troglodytes; Facial Expression; Personality; Personality Inventory
PubMed: 37934332
DOI: 10.1007/s12110-023-09462-2 -
PLoS Biology Nov 2023Tactical warfare is considered a driver of the evolution of human cognition. One such tactic, considered unique to humans, is collective use of high elevation in...
Tactical warfare is considered a driver of the evolution of human cognition. One such tactic, considered unique to humans, is collective use of high elevation in territorial conflicts. This enables early detection of rivals and low-risk maneuvers, based on information gathered. Whether other animals use such tactics is unknown. With a unique dataset of 3 years of simultaneous behavioral and ranging data on 2 neighboring groups of western chimpanzees, from the Taï National Park, Côte d'Ivoire, we tested whether chimpanzees make decisions consistent with tactical use of topography to gain an advantage over rivals. We show that chimpanzees are more likely to use high hills when traveling to, rather than away from, the border where conflict typically takes place. Once on border hills, chimpanzees favor activities that facilitate information gathering about rivals. Upon leaving hills, movement decisions conformed with lowest risk engagement, indicating that higher elevation facilitates the detection of rivals presence or absence. Our results support the idea that elevation use facilitated rival information gathering and appropriate tactical maneuvers. Landscape use during territorial maneuvers in natural contexts suggests chimpanzees seek otherwise inaccessible information to adjust their behavior and points to the use of sophisticated cognitive abilities, commensurate with selection for cognition in species where individuals gain benefits from coordinated territorial defense. We advocate territorial contexts as a key paradigm for unpicking complex animal cognition.
Topics: Animals; Humans; Pan troglodytes; Cote d'Ivoire
PubMed: 37917608
DOI: 10.1371/journal.pbio.3002350 -
Science (New York, N.Y.) Oct 2023The cognitive abilities of humans are distinctive among primates, but their molecular and cellular substrates are poorly understood. We used comparative single-nucleus...
The cognitive abilities of humans are distinctive among primates, but their molecular and cellular substrates are poorly understood. We used comparative single-nucleus transcriptomics to analyze samples of the middle temporal gyrus (MTG) from adult humans, chimpanzees, gorillas, rhesus macaques, and common marmosets to understand human-specific features of the neocortex. Human, chimpanzee, and gorilla MTG showed highly similar cell-type composition and laminar organization as well as a large shift in proportions of deep-layer intratelencephalic-projecting neurons compared with macaque and marmoset MTG. Microglia, astrocytes, and oligodendrocytes had more-divergent expression across species compared with neurons or oligodendrocyte precursor cells, and neuronal expression diverged more rapidly on the human lineage. Only a few hundred genes showed human-specific patterning, suggesting that relatively few cellular and molecular changes distinctively define adult human cortical structure.
Topics: Animals; Humans; Gene Expression Profiling; Gorilla gorilla; Hominidae; Macaca mulatta; Pan troglodytes; Phylogeny; Transcriptome; Neocortex; Species Specificity; Temporal Lobe; Cognition
PubMed: 37824638
DOI: 10.1126/science.ade9516 -
Scientific Reports Oct 2023Every evening, chimpanzees build sleeping "nests" in trees. In some studied communities, individuals appear to be selective about the tree species used, which has led...
Every evening, chimpanzees build sleeping "nests" in trees. In some studied communities, individuals appear to be selective about the tree species used, which has led researchers to hypothesize whether chimpanzees prefer trees that repel troublesome insects or/and that provide comfortable and stable structures. We investigate these hypotheses, or a trade-off between both, though study of tree species preference based on their biomechanical and/or biochemical properties in the Sebitoli chimpanzee community in Kibale National Park, Uganda. The ten tree species most frequently used for nesting were compared with ten abundant in their environment but not preferred for nesting. For these 20 tree species, we determined their biomechanical and morphological characteristics such as foliar density, foliar units form (shape and size) and branch rigidity. Their spatial repellent activity, previously tested against Anopheles gambiae was incorporated into the analysis. Chimpanzees chose tree species with medium-sized and elongated foliar units, high foliar density and branch with stiffer wood. In addition, most tree species with such mechanical and morphological properties also have mosquito repellent activity. These tree properties may provide a comfortable sleeping environment enhancing sleep quality. Finally, a comparison across chimpanzee communities would be relevant to understand whether these choices are not only ecological but also cultural.
Topics: Humans; Animals; Trees; Pan troglodytes; Sleep; Sleep Quality; Uganda; Nesting Behavior
PubMed: 37805595
DOI: 10.1038/s41598-023-44192-6 -
Scientific Reports Oct 2023HLA and disease studies by using single allele statistics have been fruitless during the last 40 years for explaining association pathogenesis of the associated...
HLA and disease studies by using single allele statistics have been fruitless during the last 40 years for explaining association pathogenesis of the associated diseases.Other approaches are necessary to untangle this puzzle. We aim to revisit complement alleleism in humans and primates for both studying MHC and disease association to complotypes and extended MHC haplotypes in order to also explain the positive directional selection of maintaining immune response genes (complement, MHC adaptive and MHC non-specific genes) that keeps these three type of genes together in a short chromosome stretch (MHC) for million years. These genes may be linked to conjointly avoid microbes attack and autoimmunity. In the present paper, it is obtained a new Bf chimpanzee allele, provisionaly named Patr-Bf*A:01,that differs from other Bf alleles by having CTG at eleventh codon of exon 2 in order to start the newly suggested methodology and explain functional and evolutionary MHC obscure aspects. Exons 1 to 6 of Ba fragment of Bf gene were obtained from chimpanzee. This new chimpanzee Factor B allele (Patr-Bf*A:01) is to be identical to a infrequent human Bf allele (SNP rs641153); it stresses the strong evolutive pressure upon certain alleles that are trans specific. It also may apply to MHC extended haplotipes which may conjointly act to start an adequate immune response. It is the first time that a complement MHC class III allele is described to undergo trans species evolution,in contrast to class I and class II alleles which had already been reported . Allelism of complement factors are again proposed for studying MHC complement genes, complotypes, and extended MHC haplotypes which may be more informative that single MHC marker studies.
Topics: Male; Animals; Humans; Alleles; Pan troglodytes; Major Histocompatibility Complex; Hominidae; Histocompatibility Antigens; Complement Factor B; Chromosomes
PubMed: 37794053
DOI: 10.1038/s41598-023-42016-1 -
Scientific Reports Oct 2023Detailed observations of animal reactions to a collapsed individual in wild are rare but essential to debates about the perception of death by nonhuman animals,...
Detailed observations of animal reactions to a collapsed individual in wild are rare but essential to debates about the perception of death by nonhuman animals, including chimpanzees. A male juvenile chimpanzee named Volta, a member of the M group in the Mahale Mountains National Park, fell from a tall tree and was temporarily incapacitated, suffering a severe concussion and nasal bone fracture. However, Volta showed signs of gradual recovery. We compared the behavior of other chimpanzees towards Volta with the previous reports on the behavior towards collapsed or recently dead group members. We found that behaviors towards Volta were similar to those observed towards collapsed or dead members. These included other-regarding behaviors and aggressive behaviors, and notably, licking of Volta's blood, which has not been previously reported. Adult males tended to be in close proximity to Volta for longer periods than adult females. The social situation with adult males including alpha male, surrounding Volta likely influenced the behavior of other individuals. Exploring the state of recovery of the injured individual, by closely approaching, directing various behaviors, and observing the reactions of the victim, and demonstrate tolerance and consideration towards the victim.
Topics: Humans; Male; Animals; Female; Pan troglodytes; Behavior, Animal; Aggression; Accidents; Social Behavior; Tanzania
PubMed: 37794020
DOI: 10.1038/s41598-023-43229-0