How supplemental feeding boosts reproductive conditions of urban squirrels

Researchers investigate the effects of supplemental feeding on various reproductive aspects of squirrels in urban areas

Ritsumeikan University

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The findings demonstrate how supplemental feeding can improve reproductive conditions of urban squirrels, offering valuable insights for promoting mammalian growth and conservation.

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Credit: Dr. Yu Takahata from Ritsumeikan University, Japan

Urbanization is rapidly growing worldwide, often bringing negative effects on wildlife through loss of habitat and disturbances such as light pollution and noise. Yet some species manage to adapt to cities, either due to their inherent traits, like boldness or being omnivorous, or by adjusting their ecological or behavioral traits to take advantage of urban resources. Among these resources, food plays a particularly important role for reproduction and survival.

Cities offer many human-related food sources, including garbage, garden plants, and food that animals steal from people. Supplementary feeding, where people intentionally feed or put food out for small birds and mammals, is another important food resource. Examples include garden bird feeding or giving nuts to squirrels in parks.  These foods usually have high calorific value, and many species depend on and benefit from them. While supplemental feeding has been shown to boost reproductive success, many recent studies have also shown that its effects can be negative and are species- and context-specific. Additionally, most previous research has focused on bird species, and the effects on reproduction of mammals remain unclear.

To bridge this gap, Dr. Yu Takahata from the Research Organization of Open Innovation and Collaboration, Ritsumeikan University, Japan, and Dr. Nobuyuki Kutsukake from the Research Center for Integrative Evolutionary Science, The Graduate University for Advanced Studies, SOKENDAI, Japan, studied the reproductive conditions of female Eurasian red squirrels living in rural and urban areas. Rural squirrels, which receive no intentional supplemental feeding, offer a clear comparison to squirrels in urban areas. “Our results provide evidence that supplemental feeding can foster reproduction and urban adaptation of wild squirrels,” explains Dr. Takahata. “This study also shows how easily human activity influences urban wildlife’s ecology.” Their study was made available online on October 20, 2025, and published in Volume 105, Issue 6 of the journal Mammalian Biology on December 1, 2025.

The study was conducted at nine sites in Obihiro City, Hokkaido, Japan, including four urban parks located in residential areas and five rural forests sites 10 kilometres away from the city central of Obihiro city. The researchers directly observed reproductive conditions of 40 female red squirrels every day during the breeding season (late March to June) from 2020 to 2022. Eurasian red squirrels typically mate from winter (January–February) until early summer (June–July), and can have up to two litters depending on their body condition.

The researchers investigated six aspects of reproductive biology of the squirrels: rate of pregnancy, age at initial pregnancy, maximum age of reproduction, birth date, number of weaned young per litter, and whether they had two litters.

The results showed that the urban females had a 24% higher pregnancy rate and gave birth about a month earlier than rural females. They also reproduced earlier, at 1 year of age, while rural females did so at 2 years of age. Reproduction was also longer in urban population, continuing up to 5 years of age, compared to 4 years in the rural population. None of the rural females raised a second litter, while 40% of urban females did. Urban squirrels weaned an average of three young per litter while rural squirrels weaned one and a half.

“These findings suggest that urban squirrels have better reproductive conditions than rural squirrels,” notes Dr. Takahata. “Together with our previous study, which showed that urban females gain higher body mass due to better dietary conditions, this study suggests strong positive effects of supplemental feeding on reproductive conditions of squirrels.”

The researchers also discussed other possible urban factors, including higher urban temperatures, artificial light and light pollution, and differences in predation pressure.

Overall, the results indicate that high-quality supplemental food can positively support mammalian population growth and conservation in urban areas. “Our findings will play a vital role in urban planning efforts aimed at improving biodiversity,” concludes Dr. Takahata. 

 

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Reference

DOI: https://doi.org/10.1007/s42991-025-00536-5

 

About Ritsumeikan University, Japan

Ritsumeikan University is one of the most prestigious private universities in Japan. Its main campus is in Kyoto, where inspiring settings await researchers. With an unwavering objective to generate social symbiotic values and emergent talents, it aims to emerge as a next-generation research-intensive university. It will enhance researcher potential by providing support best suited to the needs of young and leading researchers, according to their career stage. Ritsumeikan University also endeavors to build a global research network as a “knowledge node” and disseminate achievements internationally, thereby contributing to the resolution of social/humanistic issues through interdisciplinary research and social implementation.
Website: http://en.ritsumei.ac.jp/
Ritsumeikan University Research Report: https://www.ritsumei.ac.jp/research/radiant/eng/

 

About Dr. Yu Takahata from Ritsumeikan University, Japan

Dr. Yu Takahata is currently a senior researcher at the Research Organization of Open Innovation and Collaboration at Ritsumeikan University. She obtained her Ph.D. in 2024 from The Graduate University for Advanced Studies in Japan. She is also a Japan Society for the Promotion of Science Postdoctoral Research Fellow. Her research is focused on understanding the ecology of urban wildlife and its interaction with people.

 

Funding information

Open Access funding provided by Ritsumeikan University. This study was supported by the SOKENDAI Advanced Sciences Synergy Program (SASSP) and a Grant-in-Aid from the Japan Society for the Promotion of Science Research Fellowship (22J10522).

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Journal

Mammalian Biology

DOI

10.1007/s42991-025-00536-5 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Urban females experience better reproductive conditions than rural females in Eurasian red squirrels

Article Publication Date

1-Dec-2025

 

KLU Press Release: Open Data for Global Mobility

KLU professor Arne Heinold receives MIT Prize for Open Data

Kühne Logistics University

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KLU Assistant Professor Transportation

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Credit: KLU

Open-source tool for all modes of transport

The awarded software package enables users to calculate the shortest connection between two points worldwide across different transport modes – road, rail, or sea. “If you want to travel from Hamburg to Rome, the program can calculate the distance via the sea route. The same works for rail and road networks on all continents,” explains Heinold. “This dataset is openly available and already used in research and practice around the globe.” The package has been downloaded more than 143,000 times – an exceptional number in transport research.

A technical breakthrough in route analysis

The system is based on a novel shortest path model that integrates data from road, rail, and maritime routes, enabling consistent multimodal distance calculations – something conventional routing software cannot do. Heinold and the team cleaned and harmonized large open datasets and linked them into a unified open-source structure. “It sounds simple, but it was an enormous data effort,” Heinold explains. “We had to make sure the different sources aligned instead of contradicting each other and shortest paths were computed fast – that was the real technical breakthrough.”

International collaboration

Heinold sees the project as a prime example of collaborative open science. “What makes me proud is that researchers from the USA, Spain, and Germany came together to create a solution anyone can use. We all shared the same goal: to build a tool that calculates distances across transport modes – open, transparent, and accessible to all.” Connor Makowski, Research Associate at MIT and lead developer of the package, highlights the collaboration: “SCGraph was born out of the need to make complex transportation networks easier and reproducible to use. The fact that it evolved into such a vibrant cooperation among researchers from several countries is perhaps its greatest success – the award is a wonderful recognition of that.” The 2025 award ceremony took place during Open Data @ MIT event held on Oct. 21 at Hayden Library in Cambridge (MA).

From side project to global tool

Originally, the tool was part of a larger MIT research project that required distance calculations across various transport systems. While working on his own logistics research, Heinold came across an early version of the software, identified areas for improvement, and helped make the system more user-friendly. “Developments like this often emerge organically through collaboration,” says Heinold. “We kept refining it together until it was too useful not to share.”

 

About Kühne Logistics University (KLU)

KLU, Kühne Logistics University, is a leading, state-recognized, international university with campuses in Hamburg, Germany (headquarter), and Saigon, Vietnam. It offers English-taught Bachelor’s, Master’s, MBA, PhD, and Executive Education programs in business and management, data science and analytics, and notably, logistics and supply chain management. Named after its founder and benefactor Klaus-Michael Kühne, one of Germany’s most successful business leaders, KLU is committed to empowering contemporary leaders with a strong Operations Mindset. Accordingly, its teaching and research activities blend academic excellence with a hands-on approach to ensure real-world applicability. Emphasizing digital transformation, entrepreneurship, and sustainability, KLU shapes leaders to drive responsible and sustainable change globally. KLU holds the international AACSB accreditation, an honour bestowed upon only five percent of the world’s top business schools. Students benefit from small classes and individual support from highly research-active professors, along with integrated internships, participation in student and sports clubs, and international exchanges with prestigious partner universities. Tailored career coaching and partnerships with leading companies pave the way for successful careers.

 

Study:
Makowski, Connor and Saragih, Austin and Guter, Willem and Russell, Timothy and Heinold, Arne and Lekkakos, Spyridon, SCGraph: A Dependency-Free Python Package for Road, Rail, and Maritime Shortest Path Routing Generation and Distance Estimation (August 11, 2025). MIT Center for Transportation & Logistics Research Paper No. 2025/028, Available at SSRN: https://ssrn.com/abstract=5388845 or http://dx.doi.org/10.2139/ssrn.5388845

Source Code:
connor-makowski/scgraph: Generate real world ocean, road, and rail routes with reasonable distances all with no dependencies. 

(https://github.com/connor-makowski/scgraph)

 

Probiotics and prebiotics offer safer alternatives to antibiotics in animal agriculture

Probiotics, prebiotics, and synbiotics enhance livestock gut health, immunity, and growth while reducing dependence on antibiotics

Shinshu University

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A new study by researchers at Shinshu University highlights the essential role of gut microbiota in livestock health and productivity. The researchers show how probiotics, prebiotics, and synbiotics can safely enhance growth and immunity, and balance the growth of intestinal microbes, offering practical alternatives to antibiotics. As global restrictions on antibiotic use intensify, the findings support sustainable livestock management and contribute to reducing antimicrobial resistance risks.

Maintaining a healthy gut microbiota is increasingly recognized as a cornerstone of livestock productivity. A balanced gut microbiota enables efficient nutrient digestion, optimal immune function, and overall improved performance in livestock. However, for decades, antibiotics have been widely used as growth promoters and disease preventives—an approach that has contributed to the rise of antimicrobial-resistant (AMR) bacteria. AMR poses a global public health challenge, as resistant strains can spread from livestock to humans through food, water, or the environment. This concern has led to the approach of promoting safer food systems, enhancing overall public health and minimizing environmental hazards.

Against this backdrop, a new study led by a Ph.D. student, Mr. Rayhan Chowdhury and Dr. Takeshi Shimosato from the Graduate School of Medicine and Technology, Shinshu University, Japan, demonstrates that probiotics, prebiotics, and synbiotics (P/P/S) can play a transformative role in improving growth, strengthening immunity, and reducing antibiotic dependence in animal agriculture. Their study was published in Volume 49 of the journal Veterinary Research Communications on October 20, 2025.

Mr. Chowdhury shares the motivation behind the study, “Promoting gut health through targeted microbial interventions is a safer and more sustainable strategy than depending on antibiotic growth promoters, and we wanted to explore microbe-based options.”

To understand the effects of P/P/S, the researchers conducted a literature review of articles published between 2015 and 2025. The review highlights multiple real-world applications of P/P/S in livestock systems. Probiotics supply beneficial live microorganisms, prebiotics provide nutrients that selectively stimulate good bacteria, and synbiotics combine both for a synergistic effect. Their use as natural growth promoters can help increase weight gain and improve feed efficiency, while also enhancing nutrient digestibility. Regular supplementation may reduce the incidence of gastrointestinal infections, support immune development, and maintain microbial balance during stress or disease outbreaks. Importantly, these interventions also minimize antibiotic residues in meat, milk, and manure, helping prevent environmental contamination and ensuring safer food systems. Overall, this study outlines how P/P/S can be tailored to different livestock species and production environments, offering flexible and scalable solutions for farmers.

According to the study, the implications for society and industry are significant. By reducing antibiotic use in livestock production, P/P/S strategies help lower the selection pressure that drives antimicrobial resistance. This contributes to global health protection efforts while promoting more sustainable and ethical farming practices. With regulatory policies tightening restrictions on non-therapeutic antibiotic use, the adoption of P/P/S is likely to gain further momentum worldwide.

“We hope our work encourages farmers, policymakers, and industry stakeholders to adopt microbe-based solutions that benefit both animal and public health,” says Mr. Hassan, co-author of this publication.

The researchers were motivated by the urgent need to address AMR while ensuring continued productivity in the livestock sector. Their findings offer a scientific foundation for integrating P/P/S into animal feeding systems, providing natural, safe, and effective tools to promote livestock growth, protect immunity, and safeguard the food chain. This study further underscores the strong societal implications for promoting safer food systems and protecting public health.

 

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About Shinshu University

Shinshu University is a national university founded in 1949 and located nestling under the Japanese Alps in Nagano known for its stunning natural landscapes.

Shinshu University was selected for the Forming Japan’s Peak Research Universities (J-PEAKS) Program by the Japanese government. This initiative seeks to promote the formation of university consortia that will enhance research capabilities across Japan.

Our motto, "Powered by Nature - strengthening our network with society and applying nature to create innovative solutions for a better tomorrow" reflects the mission of fostering promising creative professionals and deepening the collaborative relationship with local communities, which leads to our contribution to regional development by innovation in various fields. We’re working on providing solutions for building a sustainable society through interdisciplinary research fields: material science (carbon, fiber and composites), biomedical science (for intractable diseases and preventive medicine) and mountain science, and aiming to boost research and innovation capability through collaborative projects with distinguished researchers from the world. For more information visit https://www.shinshu-u.ac.jp/english/ or follow us on X (Twitter) @ShinshuUni for our latest news.

About  Mr. Rayhan Chowdhury from Shinshu University, Japan

Mr. Rayhan Chowdhury is a Ph.D. student at the Graduate School of Medicine, Science and Technology, Shinshu University, Japan. His research spans public health, the COVID-19 pandemic, molecular breeding, plant physiology, and microbiology. With strong skills in polymerase chain reaction and molecular genetics, he works as a Research Assistant in Sujat Ahmed’s Molecular Genetics Laboratory. He has 23 publications and 75 citations, reflecting active scientific engagement and collaboration.

 

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Journal

Veterinary Research Communications

DOI

10.1007/s11259-025-10927-1 

Method of Research

Literature review

Subject of Research

Animals

Article Title

Gut health management in livestock: roles of probiotics, prebiotics, and synbiotics in growth, immunity, and microbiota modulation

 

Sticky beginnings: When life began to gel

Surface-bound gels may have provided the structure and chemistry for life to take root on Earth, and perhaps beyond

Hiroshima University

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Primitive gels could have concentrated and protected molecules, enabling complex chemical reactions long before cells formed.

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Credit: Nirmell Satthiyasilan

How did life begin? An international team of researchers from Japan, Malaysia, the UK, and Germany suggest that the answer may lie in sticky, surface-bound gels that existed long before the first cells.

Their insights offer a new lens for both understanding life’s origins on Earth and recognizing the possibility of life elsewhere.

The study was published online in ChemSystemsChem on Nov. 19 and will appear in an upcoming print issue.

The question of how life began has puzzled humanity for centuries. Whilst no one can travel back in time to witness the first spark of life, scientists continue to piece together plausible stories from chemistry, physics and geology.

“While many theories focus on the function of biomolecules and biopolymers, our theory instead incorporates the role of gels at the origins of life,” said Tony Z. Jia, professor at Hiroshima University and co-lead author of the paper.

In their newly proposed “prebiotic gel-first” framework, the researchers suggest how life could have originated within surface-attached gel matrices—sticky, semi-solid materials that share properties with today’s microbial biofilms, the thin layers of bacteria that grow ubiquitously on rocks, pond surfaces, and even man-made objects.

Drawing from soft-matter chemistry and insights from modern biology, the study argues that such primitive gels could have provided the necessary structure and function for early chemical systems to become increasingly complex, long before the first cells emerged.

By trapping and organizing molecules, prebiotic gels may have overcome key barriers in pre-life chemistry through allowing for molecular concentration, selective retention, and environmental buffering. Within these gels, early chemical systems might have developed proto-metabolic and self-replicating behaviors, setting the stage for biological evolution.

“This is just one theory among many in the vast landscape of origin-of-life research,” said Kuhan Chandru, research scientist at the Space Science Center, National University of Malaysia (UKM) and co-lead author of the study. “However, since the role of gels has been largely overlooked, we wanted to synthesize scattered studies into a cohesive narrative that puts primitive gels at the forefront of the discussion.”

The researchers also extend this idea to astrobiology, suggesting that similar gel-like systems might exist on other planets. These potential “Xeno-films” could be non-terrestrial analogs of biofilms, composed of different chemical building blocks uniquely available at each locale. This perspective broadens the scope of how scientists search for life beyond Earth by suggesting that perhaps structures, rather than specific chemicals, could be the next target for life detection missions.

The team plans to investigate their model experimentally by exploring how such gels, composed of simple chemicals, might have formed in early Earth conditions and what properties these gels could have provided to emerging chemical systems.

“We also hope that our work inspires others in the field to further explore this and other underexplored origins-of-life theories!” said Ramona Khanum, co-first author of the paper and a former intern at UKM.

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The University of Leeds Research Mobility Funding, the Alexander von Humboldt Foundation, the Japan Society for the Promotion of Science, and the Mizuho Foundation for the Promotion of Science supported this work.

About Hiroshima University

Since its foundation in 1949, Hiroshima University has striven to become one of the most prominent and comprehensive universities in Japan for the promotion and development of scholarship and education. Consisting of 12 schools for undergraduate level and 5 graduate schools, ranging from natural sciences to humanities and social sciences, the university has grown into one of the most distinguished comprehensive research universities in Japan. English website: https://www.hiroshima-u.ac.jp/en

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Journal

ChemSystemsChem

DOI

10.1002/syst.202500038 

Article Title

Prebiotic Gels as the Cradle of Life