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Hirsch BT, Kays R, Alavi S, Caillaud D, Havmoller R, Mares R, Crofoot M. Smarter foragers do not forage smarter: a test of the diet hypothesis for brain expansion. Proc Biol Sci 2024; 291:20240138. [PMID: 38808448 DOI: 10.1098/rspb.2024.0138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/24/2024] [Indexed: 05/30/2024] Open
Abstract
A leading hypothesis for the evolution of large brains in humans and other species is that a feedback loop exists whereby intelligent animals forage more efficiently, which results in increased energy intake that fuels the growth and maintenance of large brains. We test this hypothesis for the first time with high-resolution tracking data from four sympatric, frugivorous rainforest mammal species (42 individuals) and drone-based maps of their predominant feeding trees. We found no evidence that larger-brained primates had more efficient foraging paths than smaller brained procyonids. This refutes a key assumption of the fruit-diet hypothesis for brain evolution, suggesting that other factors such as temporal cognition, extractive foraging or sociality have been more important for brain evolution.
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Affiliation(s)
- Ben T Hirsch
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
- College of Science and Engineering, James Cook University, Townsville, Australia
| | - Roland Kays
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
- North Carolina Museum of Natural Sciences, Raleigh, NC, USA
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, USA
| | - Shauhin Alavi
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Konstanz, Germany
| | - Damien Caillaud
- Department of Anthropology, University of California, Davis, One Shields Ave., Davis, CA 95616, USA
| | - Rasmus Havmoller
- Natural History Museum of Denmark, University of Copenhagen, Kobenhavn, Denmark
| | - Rafael Mares
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
| | - Margaret Crofoot
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
- Natural History Museum of Denmark, University of Copenhagen, Kobenhavn, Denmark
- Department of Biology, University of Konstanz, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
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Basso E, Horstmann J, Rakhimberdiev E, Abad-Gómez JM, Masero JA, Gutiérrez JS, Valenzuela J, Ruiz J, Navedo JG. GPS tracking analyses reveal finely-tuned shorebird space use and movement patterns throughout the non-breeding season in high-latitude austral intertidal areas. MOVEMENT ECOLOGY 2023; 11:55. [PMID: 37658459 PMCID: PMC10474677 DOI: 10.1186/s40462-023-00411-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 07/24/2023] [Indexed: 09/03/2023]
Abstract
BACKGROUND Long-distance migratory birds spend most of their annual cycle in non-breeding areas. During this period birds must meet their daily nutritional needs and acquire additional energy intake to deal with future events of the annual cycle. Therefore, patterns of space use and movement may emerge as an efficient strategy to maintain a trade-off between acquisition and conservation of energy during the non-breeding season. However, there is still a paucity of research addressing this issue, especially in trans-hemispheric migratory birds. METHODS Using GPS-tracking data and a recently developed continuous-time stochastic process modeling framework, we analyzed fine-scale movements in a non-breeding population of Hudsonian godwits (Limosa haemastica), a gregarious long-distance migratory shorebird. Specifically, we evaluated if these extreme migrants exhibit restricted, shared, and periodic patterns of space use on one of their main non-breeding grounds in southern South America. Finally, via a generalized additive model, we tested if the observed patterns were consistent within a circadian cycle. RESULTS Overall, godwits showed finely-tuned range-residence and periodic movements (each 24-72 h), being similar between day and night. Remarkably, range-resident individuals segregated spatially into three groups. In contrast, a smaller fraction of godwits displayed unpredictable and irregular movements, adding functional connectivity within the population. CONCLUSIONS In coastal non-breeding areas where resource availability is highly predictable due to tidal cycles, range-resident strategies during both the day and night are the common pattern in a long-distance shorebird population. Alternative patterns exhibited by a fraction of non-resident godwits provide functional connectivity and suggest that the exploratory tendency may be essential for information acquisition and associated with individual traits. The methodological approach we have used contributes to elucidate how the composition of movement phases operates during the non-breeding season in migratory species and can be replicated in non-migratory species as well. Finally, our results highlight the importance of considering movement as a continuum within the annual cycle.
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Affiliation(s)
- Enzo Basso
- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.
- Programa de Doctorado en Ecología y Evolución, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
| | - Johannes Horstmann
- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
| | - Eldar Rakhimberdiev
- Department of Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - José M Abad-Gómez
- Department of Anatomy, Cell Biology and Zoology, Faculty of Sciences, University of Extremadura, Badajoz, Spain
| | - José A Masero
- Ecology in the Anthropocene, Associated Unit CSIC-UEX, Zoology, Faculty of Sciences, University of Extremadura, Badajoz, Spain
| | - Jorge S Gutiérrez
- Ecology in the Anthropocene, Associated Unit CSIC-UEX, Zoology, Faculty of Sciences, University of Extremadura, Badajoz, Spain
| | - Jorge Valenzuela
- Centro de Estudios y Conservación del Patrimonio Natural (CECPAN), Chiloé, Chile
| | - Jorge Ruiz
- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
- Estación Experimental Quempillén, Facultad de Ciencias, Universidad Austral de Chile, Chiloé, Chile
| | - Juan G Navedo
- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
- Department of Anatomy, Cell Biology and Zoology, Faculty of Sciences, University of Extremadura, Badajoz, Spain
- Estación Experimental Quempillén, Facultad de Ciencias, Universidad Austral de Chile, Chiloé, Chile
- Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile
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Benitez L, Kilian JW, Wittemyer G, Hughey LF, Fleming CH, Leimgruber P, du Preez P, Stabach JA. Precipitation, vegetation productivity, and human impacts control home range size of elephants in dryland systems in northern Namibia. Ecol Evol 2022; 12:e9288. [PMID: 36177134 PMCID: PMC9471278 DOI: 10.1002/ece3.9288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/29/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022] Open
Abstract
Climatic variability, resource availability, and anthropogenic impacts heavily influence an animal's home range. This makes home range size an effective metric for understanding how variation in environmental factors alter the behavior and spatial distribution of animals. In this study, we estimated home range size of African elephants (Loxodonta africana) across four sites in Namibia, along a gradient of precipitation and human impact, and investigated how these gradients influence the home range size on regional and site scales. Additionally, we estimated the time individuals spent within protected area boundaries. The mean 50% autocorrelated kernel density estimate for home range was 2200 km2 [95% CI:1500–3100 km2]. Regionally, precipitation and vegetation were the strongest predictors of home range size, accounting for a combined 53% of observed variation. However, different environmental covariates explained home range variation at each site. Precipitation predicted most variation (up to 74%) in home range sizes (n = 66) in the drier western sites, while human impacts explained 71% of the variation in home range sizes (n = 10) in Namibia's portion of the Kavango‐Zambezi Transfrontier Conservation Area. Elephants in all study areas maintained high fidelity to protected areas, spending an average of 85% of time tracked on protected lands. These results suggest that while most elephant space use in Namibia is driven by natural dynamics, some elephants are experiencing changes in space use due to human modification.
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Affiliation(s)
- Lorena Benitez
- Smithsonian National Zoo & Conservation Biology Institute Front Royal Virginia USA
| | - J Werner Kilian
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism Okaukuejo Namibia
| | - George Wittemyer
- Department of Fish, Wildlife, and Conservation Biology Colorado State University Fort Collins Colorado USA.,Save the Elephants Nairobi Kenya
| | - Lacey F Hughey
- Smithsonian National Zoo & Conservation Biology Institute Front Royal Virginia USA
| | - Chris H Fleming
- Smithsonian National Zoo & Conservation Biology Institute Front Royal Virginia USA.,Department of Biology University of Maryland Maryland USA
| | - Peter Leimgruber
- Smithsonian National Zoo & Conservation Biology Institute Front Royal Virginia USA
| | | | - Jared A Stabach
- Smithsonian National Zoo & Conservation Biology Institute Front Royal Virginia USA
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