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Beltran RS, Lozano RR, Morris PA, Robinson PW, Holser RR, Keates TR, Favilla AB, Kilpatrick AM, Costa DP. Individual variation in life-history timing: synchronous presence, asynchronous events and phenological compensation in a wild mammal. Proc Biol Sci 2024; 291:20232335. [PMID: 38628129 PMCID: PMC11021928 DOI: 10.1098/rspb.2023.2335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024] Open
Abstract
Many animals and plants have species-typical annual cycles, but individuals vary in their timing of life-history events. Individual variation in fur replacement (moult) timing is poorly understood in mammals due to the challenge of repeated observations and longitudinal sampling. We examined factors that influence variation in moult duration and timing among elephant seals (Mirounga angustirostris). We quantified the onset and progression of fur loss in 1178 individuals. We found that an exceptionally rapid visible moult (7 days, the shortest of any mammals or birds), and a wide range of moult start dates (spanning 6-10× the event duration) facilitated high asynchrony across individuals (only 20% of individuals in the population moulting at the same time). Some of the variation was due to reproductive state, as reproductively mature females that skipped a breeding season moulted a week earlier than reproductive females. Moreover, individual variation in timing and duration within age-sex categories far outweighed (76-80%) variation among age-sex categories. Individuals arriving at the end of the moult season spent 50% less time on the beach, which allowed them to catch up in their annual cycles and reduce population-level variance during breeding. These findings underscore the importance of individual variation in annual cycles.
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Affiliation(s)
- Roxanne S. Beltran
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Raquel R. Lozano
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Patricia A. Morris
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Patrick W. Robinson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Rachel R. Holser
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Theresa R. Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Arina B. Favilla
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - A. Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Daniel P. Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA
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Ortega AC, Merkle JA, Sawyer H, Monteith KL, Lionberger P, Valdez M, Kauffman MJ. A test of the frost wave hypothesis in a temperate ungulate. Ecology 2024; 105:e4238. [PMID: 38212148 DOI: 10.1002/ecy.4238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 09/25/2023] [Accepted: 11/10/2023] [Indexed: 01/13/2024]
Abstract
Growing evidence supports the hypothesis that temperate herbivores surf the green wave of emerging plants during spring migration. Despite the importance of autumn migration, few studies have conceptualized resource tracking of temperate herbivores during this critical season. We adapted the frost wave hypothesis (FWH), which posits that animals pace their autumn migration to reduce exposure to snow but increase acquisition of forage. We tested the FWH in a population of mule deer in Wyoming, USA by tracking the autumn migrations of n = 163 mule deer that moved 15-288 km from summer to winter range. Migrating deer experienced similar amounts of snow but 1.4-2.1 times more residual forage than if they had naïve knowledge of when or how fast to migrate. Importantly, deer balanced exposure to snow and forage in a spatial manner. At the fine scale, deer avoided snow near their mountainous summer ranges and became more risk prone to snow near winter range. Aligning with their higher tolerance of snow and lingering behavior to acquire residual forage, deer increased stopover use by 1 ± 1 day (95% CI) day for every 10% of their migration completed. Our findings support the prediction that mule deer pace their autumn migration with the onset of snow and residual forage, but refine the FWH to include movement behavior en route that is spatially dynamic.
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Affiliation(s)
- Anna C Ortega
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
- Program in Ecology, University of Wyoming, Laramie, Wyoming, USA
| | - Jerod A Merkle
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Hall Sawyer
- Western Ecosystems Technology, Inc., Laramie, Wyoming, USA
| | - Kevin L Monteith
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
- Haub School of Environment and Natural Resources, University of Wyoming, Laramie, Wyoming, USA
| | - Patrick Lionberger
- Bureau of Land Management, Rock Springs Field Office, Rock Springs, Wyoming, USA
| | - Miguel Valdez
- Bureau of Land Management, Rock Springs Field Office, Rock Springs, Wyoming, USA
| | - Matthew J Kauffman
- US Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
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McInnes JD, Lester KM, Dill LM, Mathieson CR, West-Stap PJ, Marcos SL, Trites AW. Foraging behaviour and ecology of transient killer whales within a deep submarine canyon system. PLoS One 2024; 19:e0299291. [PMID: 38507673 PMCID: PMC10954312 DOI: 10.1371/journal.pone.0299291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/08/2024] [Indexed: 03/22/2024] Open
Abstract
Transient killer whales have been documented hunting marine mammals across a variety of habitats. However, relatively little has been reported about their predatory behaviours near deep submarine canyons and oceanic environments. We used a long-term database of sightings and encounters with these predators in and around the Monterey Submarine Canyon, California to describe foraging behaviour, diet, seasonal occurrence, and habitat use patterns. Transient killer whales belonging to the outer coast subpopulation were observed within the study area 261 times from 2006-2021. Occurrences, behaviours, and group sizes all varied seasonally, with more encounters occurring in the spring as grey whales migrated northward from their breeding and calving lagoons in Mexico (March-May). Groups of killer whales foraged exclusively in open water, with individuals within the groups following the contours of the submarine canyon as they searched for prey. Focal follows revealed that killer whales spent 51% of their time searching for prey (26% of their time along the shelf-break and upper slope of the canyon, and 25% in open water). The remainder of their time was spent pursuing prey (10%), feeding (23%), travelling (9%), socializing (6%), and resting (1%). Prey species during 87 observed predation events included California sea lions, grey whale calves, northern elephant seals, minke whales, common dolphins, Pacific white-sided dolphins, Dall's porpoise, harbour porpoise, harbour seals, and sea birds. The calculated kill rates (based on 270 hours of observing 50 predation events) were 0.26 California sea lions per killer whale over 24 hours, 0.11 grey whale calves, and 0.15 for all remaining prey species combined. These behavioural observations provide insights into predator-prey interactions among apex predators over submarine canyons and deep pelagic environments.
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Affiliation(s)
- Josh D. McInnes
- Institute for the Oceans and Fisheries, Marine Mammal Research Unit, University of British Columbia, Vancouver, Canada
- Pacific WildLife Foundation, Port Moody, BC, Canada
- Oceanic Ecology Research Group, Monterey Bay, California, United States of America
| | - Kevin M. Lester
- Oceanic Ecology Research Group, Monterey Bay, California, United States of America
| | - Lawrence M. Dill
- Department of Biological Sciences, Evolutionary and Behavioural Ecology Research Group, Simon Fraser University, Burnaby, Canada
| | - Chelsea R. Mathieson
- Oceanic Ecology Research Group, Monterey Bay, California, United States of America
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, Canada
| | | | | | - Andrew W. Trites
- Institute for the Oceans and Fisheries, Marine Mammal Research Unit, University of British Columbia, Vancouver, Canada
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Oosthuizen WC, Pistorius PA, Bester MN, Altwegg R, de Bruyn PJN. Reproductive phenology is a repeatable, heritable trait linked to the timing of other life-history events in a migratory marine predator. Proc Biol Sci 2023; 290:20231170. [PMID: 37464761 PMCID: PMC10354465 DOI: 10.1098/rspb.2023.1170] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 06/26/2023] [Indexed: 07/20/2023] Open
Abstract
Population-level shifts in reproductive phenology in response to environmental change are common, but whether individual-level responses are modified by demographic and genetic factors remains less well understood. We used mixed models to quantify how reproductive timing varied across 1772 female southern elephant seals (Mirounga leonina) breeding at Marion Island in the Southern Ocean (1989-2019), and to identify the factors that correlate with phenological shifts within and between individuals. We found strong support for covariation in the timing of breeding arrival dates and the timing of the preceding moult. Breeding arrival dates were more repeatable at the individual level, as compared with the population level, even after accounting for individual traits (wean date as a pup, age and breeding experience) associated with phenological variability. Mother-daughter similarities in breeding phenology were also evident, indicating that additive genetic effects may contribute to between-individual variation in breeding phenology. Over 30 years, elephant seal phenology did not change towards earlier or later dates, and we found no correlation between annual fluctuations in phenology and indices of environmental variation. Our results show how maternal genetic (or non-genetic) effects, individual traits and linkages between cyclical life-history events can drive within- and between-individual variation in reproductive phenology.
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Affiliation(s)
- W C Oosthuizen
- Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town 7701, South Africa
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, Gqeberha 6031, South Africa
| | - P A Pistorius
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, Gqeberha 6031, South Africa
| | - M N Bester
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
| | - R Altwegg
- Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town 7701, South Africa
| | - P J N de Bruyn
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
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Maaß E, Miersch L, Pfuhl G, Hanke FD. A harbour seal (Phoca vitulina) can learn geometrical relationships between landmarks. J Exp Biol 2022; 225:285956. [PMID: 36448922 DOI: 10.1242/jeb.244544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 11/11/2022] [Indexed: 12/05/2022]
Abstract
Marine mammals travel the world's oceans. Some species regularly return to specific places to breathe, haul-out or breed. However, the mechanisms they use to return are unknown. Theoretically, landmarks could mediate the localisation of these places. Occasionally, it might be beneficial or even required to localise places using geometrical information provided by landmarks such as to apply a 'middle rule'. Here, we trained a harbour seal to find its goal in the middle of numerous vertically and horizontally orientated two-landmark arrays. During testing, the seal was confronted with unfamiliar two-landmark arrays. After having successfully learnt to respond to the midpoint of multiple two-landmark arrays, the seal directly and consistently followed a 'middle rule' during testing. It chose the midpoint of the two-landmark arrays with high precision. Harbour seals with the ability to localise goals based on geometrical information would be able to home in on places even from unknown positions relative to goal-defining features. Altogether, the results obtained with our harbour seal individual in the present and a previous study, examining the basis of landmark orientation, provide evidence that this seal can use landmark information very flexibly. Depending on context, this flexibility is adaptive to an environment in which the information content can vary over time.
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Affiliation(s)
- Eric Maaß
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Lars Miersch
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Gerit Pfuhl
- Norwegian University of Science and Technology, Postbox 8900 Torgarden, 7491 Trondheim, Norway
| | - Frederike D Hanke
- University of Rostock, Institute for Biosciences, Neuroethology, Albert-Einstein-Str. 3, 18059 Rostock, Germany
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Oestreich WK, Aiu KM, Crowder LB, McKenna MF, Berdahl AM, Abrahms B. The influence of social cues on timing of animal migrations. Nat Ecol Evol 2022; 6:1617-1625. [DOI: 10.1038/s41559-022-01866-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 08/01/2022] [Indexed: 11/09/2022]
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