Captive bottlenose dolphins vary vocalizations during enrichment activities

Study suggests the frequency, and duration of vocalizations reflect cognitive engagement

PLOS

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Positioning of the recording device (red circle) in the “Laguna dei delfini” pool.

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Credit: Screpanti et al., 2025, PLOS One, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Dolphins produce a range of vocalizations used for echolocation and communication. These vocalizations vary with social context, environmental conditions, external stimuli, and communication, reflecting their cognitive and behavioral complexity. A study published in PLOS One on December 3, 2025 by Francesco Di Nardo at Università Politecnica delle Marche, Ancona, Italy and colleagues suggests that the frequency and duration of captive dolphin vocalizations may indicate engagement with structured activities.

Captive dolphins require enrichment activities, such as training sessions and play interactions. However, best practices for managing captive dolphin environments and optimizing welfare practices could be improved with a more detailed understanding of what activities motivate and engage them.

In order to better understand the relationship between vocal behavior and different kinds of structured activities, researchers conducted acoustic analyses of seven bottlenose dolphins (Tursiops truncatus) at Oltremare Marine Park in Ricci­one, Italy. Researchers recorded the vocalizations of two males and five females over a 24-hour period in 2021 while monitoring the dolphins’ environment and activities, including feeding sessions and trainer-led exercises. Researchers then analyzed the recordings to classify vocalizations as whistles and pulses, quantified their diversity, number, and duration, and compared periods of organized activity with periods of no organized activity.

The researchers found that organized activities influenced all vocalizations, reflecting increased motivation, social coordination, and negotiation with fellow dolphins, as well as engagement with human trainers. The study was limited by its small sample size of seven dolphins and short study duration of one day. Future research focusing on comparisons between different types of activities and environments rather than comparing activity to periods of no activity could yield richer insights about the enrichment needs of captive dolphins.

According to the authors, “Understanding the relationship between vocalization patterns and activity types has direct implications for dolphin welfare. Our study can improve the design of enrichment programs to ensure that dolphins in human care maintain a healthy and dynamic acoustic repertoire.”

The authors also add: “The goal of our study was to understand how dolphins adjust their vocal behavior throughout the various activities of one day at Oltremare Marine Park (Riccione, Italy). Our findings show that dolphins tend to ‘speak’ much more during structured moments like training, feeding, or play, revealing how closely their vocal activity reflects their social and emotional engagement. This work also illustrates how detailed acoustic datasets can deepen our understanding of dolphin communication and support better welfare and conservation practices. Alongside the scientific analysis, indeed, this study also releases the full database of dolphin vocalizations in the hope that it will support and inspire further research. Working with these highly social animals is truly inspiring; they remind us how much we can learn about the marine environment and the relationships among its inhabitants.”

“The authors would like to highlight that this work was carried out through a collaboration among Università Politecnica delle Marche (Ancona, Italy), IRBIM – CNR (Ancona, Italy), and Oltremare Marine Park (Riccione, RN, Italy).”

 

 

In your coverage, please use this URL to provide access to the freely available article in PLOS One: https://plos.io/43Hi8Wf

Citation: Screpanti L, Di Nardo F, De Marco R, Furlati S, Bucci G, Lucchetti A, et al. (2025) Acoustic analysis of bottlenose dolphin vocalizations for behavioral classification in controlled settings. PLoS One 20(12): e0336419. https://doi.org/10.1371/journal.pone.0336419

Author countries: Italy

Funding: This work was supported in part by LIFE Financial Instrument of the European Community, Life Delfi Project – Dolphin Experience: Lowering Fishing Interactions (LIFE18NAT/IT/000942) and by the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.4 (Call for tender No. 3138 of 16 December 2021, rectified by Decree n.3175 of 18 December 2021 of Italian Ministry of University and Research funded by the European Union) NextGenerationEU. The study was made possible through the support and collaboration of Costa Edutainment, which provided access to their Riccione facility. Special acknowledgment is given to Barbara Marchiori, Gianni Bucci, Barbara Acciai, Paola Righetti, and Claudia Di Mecola for their dedicated contributions and support during the project. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study.

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Journal

PLOS One

DOI

10.1371/journal.pone.0336419 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Acoustic analysis of bottlenose dolphin vocalizations for behavioral classification in controlled settings

Article Publication Date

3-Dec-2025

 

Bumblebees launch a three-stage defensive response when their nest is disturbed

In the lab, bumblebees increased activity, searched for and warned intruders, then calmed down

PLOS

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A bumble bee performing the disturbance leg-lift response.

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Credit: Elisabeth Böker, PLOS One, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Bumblebees respond to physical disturbance of their nest with a sequence of defensive behaviors that lasts up to 10 minutes, according to a study by Sajedeh Sarlak at the University of Konstanz, Germany, and colleagues, publishing December 3, 2025 in the open-access journal PLOS One.

Although we often think of bumblebees as docile, friendly garden visitors, they will fiercely defend their nest if needed. Bumblebees are important pollinators for both wild plants and crops, and they are often kept in commercial greenhouses, so understanding their defensive behavior is important for both conservation and health and safety. However, relatively little is known about how they respond to nest disturbance.

To investigate, researchers studied commercially reared bumblebee (Bombus terrestris) colonies in the laboratory. They disturbed the bees with a mechanical jolt — mimicking an attack by a badger or a human — and collected video and audio recordings of their response. When the nest was disturbed, the bees immediately sprang into action, moving around faster, patrolling the nest, flying and climbing the nest walls, suggesting that they were searching for the source of the disturbance. This state of heightened activity lasted for several minutes.

Immediately after the disturbance, bees also often buzzed their wings or raised their legs. Leg-lifting is a warning that they are ready to sting, whereas buzzing might alert other bees to the threat, or serve as a warning to the intruder. Between 1 and 3 minutes after the disturbance, bees began grooming themselves and making short, rhythmic sequences of buzzes. These behaviors may have a calming effect, reducing stress after the threat has subsided, though the authors note that this buzzing could also serve to maintain alarm, and further study is needed before conclusions can be drawn.  

The results show that when their nest is disturbed, bumblebees respond by preparing to defend the nest, searching for the threat, warning potential intruders to stay away, and finally, recovering from the stress of the disturbance. They maintain a state of heightened vigilance for around 4 minutes, which may help them to react quickly if the threat returns. The study provides a comprehensive overview of bumblebee defensive behavior, which is a starting point for future research, the authors say.

Morgane Nouvian adds: “To me, this study is really a starting point. We describe the sequence of responses that follows a disturbance, and in doing so we are raising so many questions! What are the functions of these behaviors? Is this defensive response regulated by social or environmental factors? Some behaviors are not performed by all bees, are these responders specialized in defense?”

 

 

In your coverage, please use this URL to provide access to the freely available article in PLOS One: https://plos.io/4i9YeZO

Citation: Sarlak S, Ramesh D, Ashouri A, Goldansaz SH, Schwarz A, Seitz L, et al. (2025) Colony defence in bumblebees (Bombus terrestris). PLoS One 20(12): e0335136. https://doi.org/10.1371/journal.pone.0335136

Author countries: Iran, Germany

Funding: This research was supported by the Zukunftskolleg at the University of Konstanz and by a grant from the University of Tehran Research Vice-Chancellor, Ministry of Science, Research and Technology, and Iranian National Science Foundation (project number 97011974). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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Journal

PLOS One

DOI

10.1371/journal.pone.0335136 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Colony defence in bumblebees (Bombus terrestris)

Article Publication Date

3-Dec-2025

Authoritative parenting styles are associated with better mental health and self-esteem among adolescents, while authoritarian parenting styles are associated with depression and lower self-esteem and permissive parenting styles are associated with stress, according to Nepalese study of 583 adolescents

Article URL: https://plos.io/44lRwtW

Article title: Relationship of parenting styles on depression, anxiety, stress and self-esteem of adolescents

Author countries: Nepal

Funding: The author(s) received no specific funding for this work.

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Journal

PLOS One

DOI

10.1371/journal.pone.0332854 

Article Title

Relationship of parenting styles on depression, anxiety, stress and self-esteem of adolescents

Article Publication Date

3-Dec-2025

COI Statement

The authors have declared that no competing interests exist.

 

Sperm tails and male infertility: Critical protein revealed by ultrastructure microscope

RIKEN

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Ultrastructure expansion microscopy of murine male germ cells reveals the fine molecular structures of centrioles (shown in the enlarged image). DNA is stained in blue, and the chromosome axis in red.

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Credit: RIKEN

Male infertility is a major issue worldwide and its causes remain unclear. Now, an international team of researchers led by Hiroki Shibuya at the RIKEN Center for Biosystems Dynamics Research (BDR) in Japan has discovered a key structure in the germ cells of male mice that, when disturbed, leads to deformations in sperm flagellum—the tail that allows sperm to swim. Made possible by the first observation of the mouse flagellar base structure using ultrastructure expansion microscopy, this finding could explain some forms of infertility in human men. The study was published in the scientific journal Science Advances.

When conception fails, it is often due to abnormalities in egg or sperm cells that occur during their development. In males, this process is called spermatogenesis and continues throughout life after puberty. Although we know a little bit about this process, scientists have yet to map everything that happens at the subcellular level.

“While the causes of female infertility have been studied extensively,” says Shibuya, “the mechanisms underlying male infertility—which are known to account for about half of all infertility cases—remain poorly understood.”

Shibuya and his team tackled this problem using a relatively new technology called ultrastructure expansion microscopy. Detailed images of the insides of cells can already be taken with an electron microscope. But you cannot identify specific proteins or track how a structure changes over time. On the other hand, fluorescent microscopy can’t normally visualize ultrastructures inside a cell. With ultrastructure expansion microscopy, the cells of interest are placed on a gel. The gel is then expanded many times its original size. Now standard immunofluorescence labeling combined with a fluorescent microscope can be used to look at the giant specimen and specific ultrastructures can be imaged with high resolution.

The researchers adapted this relatively new technology for male mouse germ cells by gently fixing and drying the cells onto coverslips before putting them in the gel. This prevented the cells from moving around, which is a problem for male germ cells. They also applied a treatment to remove excess cytoplasm, which improved the resolution.

Having solved these issues, Shibuya and his team focused their efforts on the centriole, a tiny cylindrical structure—only 450 nanometers in length and 200 nanometers in diameter—that undergoes major changes during spermatogenesis that allow the flagellum to form. A correctly formed flagellum is critical because without it, sperm cannot move properly and will never even reach an egg cell, let alone fertilize it. Using their modified protocol, the researchers were able to visualize both the proximal and distal centriole throughout the entire transformation from germ cell to sperm.

They found that the inner scaffold within the distal centriole becomes stronger after the completion of meiosis, when germ cells divide and the new cells contain only one copy of each gene. Fluorescent labeling of key proteins that make up the distal centriole inner scaffold showed an increase in centrin-POC5 protein complexes. How important are these proteins for fertility? A complete knockout of POC5 using CRISPR gene editing produced normal male mice with zero viable sperm. Detailed analysis revealed that while centriole function in regular cells was unaffected, the lack of POC5 caused malformed flagella that disintegrated, explaining why the mice were completely infertile.

“Our modified expansion microscopy protocol can be extended to other analyses, including human sperm, opening new possibilities for investigating fine structural abnormalities that account for male infertility,” says Shibuya. “In the long-term, this could lead to novel diagnostic and therapeutic approaches in reproductive medicine.”

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Journal

Science Advances

DOI

10.1126/sciadv.aea4045 

 

To make AI more fair, tame complexity

Biases in AI models can be reduced by better reflecting the complexities of the real world

University of Texas at Austin

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In April, OpenAI’s popular ChatGPT hit a milestone of a billion active weekly users, as artificial intelligence continued its explosion in popularity.

But with that popularity has come a dark side. Biases in AI’s models and algorithms can actively harm some of its users and promote social injustice. Documented biases have led to different medical treatments due to patients’ demographics and corporate hiring tools that discriminate against female and Black candidates.

New research from Texas McCombs suggests both a previously unexplored source of AI biases and some ways to correct for them: complexity.

“There’s a complex set of issues that the algorithm has to deal with, and it’s infeasible to deal with those issues well,” says Hüseyin Tanriverdi, associate professor of information, risk, and operations management. “Bias could be an artifact of that complexity rather than other explanations that people have offered.”

With John-Patrick Akinyemi, a McCombs Ph.D. candidate in IROM, Tanriverdi studied a set of 363 algorithms that researchers and journalists had identified as biased. The algorithms came from a repository called AI Algorithmic and Automation Incidents and Controversies.

The researchers compared each problematic algorithm with one that was similar in nature but had not been called out for bias. They examined not only the algorithms but also the organizations that created and used them.

Prior research has assumed that bias can be reduced by making algorithms more accurate. But that assumption, Tanriverdi found, did not tell the whole story. He found three additional factors, all related to a similar problem: not properly modeling for complexity.

Ground truth. Some algorithms are asked to make decisions when there’s no established ground truth: the reference against which the algorithm’s outcomes are evaluated. An algorithm might be asked to guess the age of a bone from an X-ray image, even though in medical practice, there’s no established way for doctors to do so.

In other cases, AI may mistakenly treat opinions as objective truths — for example, when social media users are evenly split on whether a post constitutes hate speech or protected free speech.

AI should only automate decisions for which ground truth is clear, Tanriverdi says. “If there is not a well-established ground truth, then the likelihood that bias will emerge significantly increases.”

Real-world complexity. AI models inevitably simplify the situations they describe. Problems can arise when they miss important components of reality.

Tanriverdi points to a case in which Arkansas replaced home visits by nurses with automated rulings on Medicaid benefits. It had the effect of cutting off disabled people from assistance with eating and showering.

“If a nurse goes and walks around to the house, they will be able to understand more about what kind of support this person needs,” he says. “But algorithms were using only a subset of those variables, because data was not available on everything.

“Because of omission of the relevant variables in the model, that model was no longer a good enough representation of reality.”

Stakeholder involvement.  When a model serving a diverse population is designed mostly by members of a single demographic, it becomes more susceptible to bias. One way to counter this risk is to ensure that all stakeholder groups have a voice in the development process.

By involving stakeholders who may have conflicting goals and expectations, an organization can determine whether it’s possible to meet them all. If it’s not, Tanriverdi says, “It may be feasible to reach compromise solutions that everyone is OK with.”

The research concludes that taming AI bias involves much more than making algorithms more accurate. Developers need to open up their black boxes to account for real-world complexities, input from diverse groups, and ground truths.

“The factors we focus on have a direct effect on the fairness outcome,” Tanriverdi says. “These are the missing pieces that data scientists seem to be ignoring.”

“Algorithmic Social Injustice: Antecedents and Mitigations”  is published in MIS Quarterly.

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Journal

MIS Quarterly

DOI

10.25300/MISQ/2025/18314 

Article Title

Algorithmic Social Injustices: Antecedents and Mitigations

Article Publication Date

1-Dec-2025