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Furrer M, Meier SA, Jan M, Franken P, Sundset MA, Brown SA, Wagner GC, Huber R. Reindeer in the Arctic reduce sleep need during rumination. Curr Biol 2024; 34:427-433.e5. [PMID: 38141616 DOI: 10.1016/j.cub.2023.12.012] [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: 09/02/2023] [Revised: 11/24/2023] [Accepted: 12/06/2023] [Indexed: 12/25/2023]
Abstract
Timing and quantity of sleep depend on a circadian (∼24-h) rhythm and a specific sleep requirement.1 Sleep curtailment results in a homeostatic rebound of more and deeper sleep, the latter reflected in increased electroencephalographic (EEG) slow-wave activity (SWA) during non-rapid eye movement (NREM) sleep.2 Circadian rhythms are synchronized by the light-dark cycle but persist under constant conditions.3,4,5 Strikingly, arctic reindeer behavior is arrhythmic during the solstices.6 Moreover, the Arctic's extreme seasonal environmental changes cause large variations in overall activity and food intake.7 We hypothesized that the maintenance of optimal functioning under these extremely fluctuating conditions would require adaptations not only in daily activity patterns but also in the homeostatic regulation of sleep. We studied sleep using non-invasive EEG in four Eurasian tundra reindeer (Rangifer tarandus tarandus) in Tromsø, Norway (69°N) during the fall equinox and both solstices. As expected, sleep-wake rhythms paralleled daily activity distribution, and sleep deprivation resulted in a homeostatic rebound in all seasons. Yet, these sleep rebounds were smaller in summer and fall than in winter. Surprisingly, SWA decreased not only during NREM sleep but also during rumination. Quantitative modeling revealed that sleep pressure decayed at similar rates during the two behavioral states. Finally, reindeer spent less time in NREM sleep the more they ruminated. These results suggest that they can sleep during rumination. The ability to reduce sleep need during rumination-undisturbed phases for both sleep recovery and digestion-might allow for near-constant feeding in the arctic summer.
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Affiliation(s)
- Melanie Furrer
- Child Development Center and Children's Research Center, University Children's Hospital Zurich, University of Zurich, Steinwiesstrasse 75, 8032 Zurich, Switzerland
| | - Sara A Meier
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Maxime Jan
- Center for Integrative Genomics, University of Lausanne, Génopode building, 1015 Lausanne, Switzerland; Bioinformatics Competence Center, University of Lausanne, Génopode building, 1015 Lausanne, Switzerland
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, Génopode building, 1015 Lausanne, Switzerland
| | - Monica A Sundset
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway
| | - Steven A Brown
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Gabriela C Wagner
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway; Division of Forest and Forest Resources, Norwegian Institute of Bioeconomy Research, Holtvegen 66, 9016 Tromsø, Norway.
| | - Reto Huber
- Child Development Center and Children's Research Center, University Children's Hospital Zurich, University of Zurich, Steinwiesstrasse 75, 8032 Zurich, Switzerland; Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric Hospital Zurich, University of Zurich, Lenggstrasse 31, 8032 Zurich, Switzerland.
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2
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Gübert J, Schneider G, Hahn‐Klimroth M, Dierkes PW. Nocturnal behavioral patterns of African ungulates in zoos. Ecol Evol 2023; 13:e10777. [PMID: 38053790 PMCID: PMC10694388 DOI: 10.1002/ece3.10777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 11/08/2023] [Accepted: 11/14/2023] [Indexed: 12/07/2023] Open
Abstract
Currently, most studies on ungulates' behavior are conducted during the daylight hours, but their nocturnal behavior patterns differ from those shown during day. Therefore, it is necessary to observe ungulates' behavior also overnight. Detailed analyses of nocturnal behavior have only been conducted for very prominent ungulates such as Giraffes (Giraffa camelopardalis), African Elephants (Loxodonta africana), or livestock (e.g., domesticated cattle, sheep, or pigs), and the nocturnal rhythms exhibited by many ungulates remain unknown. In the present study, the nocturnal rhythms of 192 individuals of 18 ungulate species from 20 European zoos are studied with respect to the behavioral positions standing, lying-head up, and lying-head down (the typical REM sleep position). Differences between individuals of different age were found, but no differences with respect to the sex were seen. Most species showed a significant increase in the proportion of lying during the night. In addition, the time between two events of "lying down" was studied in detail. A high degree of rhythmicity with respect to this quantity was found in all species. The proportion of lying in such a period was greater in Artiodactyla than in Perissodactyla, and greater in juveniles than in adults.
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Affiliation(s)
- Jennifer Gübert
- Faculty of Biological SciencesGoethe University FrankfurtFrankfurtGermany
| | - Gaby Schneider
- Institute of MathematicsGoethe University FrankfurtFrankfurtGermany
| | | | - Paul W. Dierkes
- Faculty of Biological SciencesGoethe University FrankfurtFrankfurtGermany
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3
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Lyamin OI, Siegel JM, Nazarenko EA, Vu M, Rozhnov VV. Sleep with Open Eyes in Two Species of Deer, the Indian Sambar (Rusa unicolor) and Sika Deer (Cervus nippon). DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2023; 512:295-299. [PMID: 38087016 DOI: 10.1134/s0012496623700679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/06/2023] [Accepted: 07/10/2023] [Indexed: 12/18/2023]
Abstract
The relationship between postures, sleep stages and eye state was established in two species of deer, the Indian sambar (Rusa unicolor) and sika deer (Cervus nippon), based on video recording. In both species, the state of rest or behavioral sleep was recorded in the sternal position, holding the head above the ground, and in the lateral position, with the head resting on the croup or on the ground. Rest accounted for at least 80% of the time in these positions. Based on behavior criteria a substantial portion of rest represented slow-wave sleep. Episodes of rapid eye movements (REM sleep) were recorded in the lateral position. They did not exceed 2 min. When the deer were in the sternal posture, they kept their eyes open most of the time: in average 96% of the time in sambars and 82% in sika deer. Episodes of the open eye in this posture lasted up to 8.4 min in sambars and up to 3.3 min in sika deer. In the lateral position, such episodes were 4 and 1.5 times shorter. Sleeping with open eyes in ungulates may be an important mechanism of maintaining vigilance.
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Affiliation(s)
- O I Lyamin
- Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Moscow, Russia.
- Joint Russian-Vietnam Tropical Research and Technological Center, Hanoi, Vietnam.
- University of California in Los Angeles, Los Angeles, USA.
| | - J M Siegel
- University of California in Los Angeles, Los Angeles, USA
| | - E A Nazarenko
- Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Moscow, Russia
- Joint Russian-Vietnam Tropical Research and Technological Center, Hanoi, Vietnam
| | - Manh Vu
- Joint Russian-Vietnam Tropical Research and Technological Center, Hanoi, Vietnam
| | - V V Rozhnov
- Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Moscow, Russia
- Joint Russian-Vietnam Tropical Research and Technological Center, Hanoi, Vietnam
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Kendall-Bar JM, Williams TM, Mukherji R, Lozano DA, Pitman JK, Holser RR, Keates T, Beltran RS, Robinson PW, Crocker DE, Adachi T, Lyamin OI, Vyssotski AL, Costa DP. Brain activity of diving seals reveals short sleep cycles at depth. Science 2023; 380:260-265. [PMID: 37079694 DOI: 10.1126/science.adf0566] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
Sleep is a crucial part of the daily activity patterns of mammals. However, in marine species that spend months or entire lifetimes at sea, the location, timing, and duration of sleep may be constrained. To understand how marine mammals satisfy their daily sleep requirements while at sea, we monitored electroencephalographic activity in wild northern elephant seals (Mirounga angustirostris) diving in Monterey Bay, California. Brain-wave patterns showed that seals took short (less than 20 minutes) naps while diving (maximum depth 377 meters; 104 sleeping dives). Linking these patterns to accelerometry and the time-depth profiles of 334 free-ranging seals (514,406 sleeping dives) revealed a North Pacific sleepscape in which seals averaged only 2 hours of sleep per day for 7 months, rivaling the record for the least sleep among all mammals, which is currently held by the African elephant (about 2 hours per day).
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Affiliation(s)
- Jessica M Kendall-Bar
- Scripps Institution of Oceanography, University of California San Diego, San Diego, CA, USA
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Terrie M Williams
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Ritika Mukherji
- Department of Neuroscience, University of Oxford, Oxford, UK
| | - Daniel A Lozano
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | | | - Rachel R Holser
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Theresa Keates
- Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Roxanne S Beltran
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Patrick W Robinson
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Taiki Adachi
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Oleg I Lyamin
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA
- A.N. Severtsov Institute of Ecology and Evolution, Moscow, Russia
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich and Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Daniel P Costa
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
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Zaid E, Vyssotski AL, Lesku JA. Sleep architecture and regulation of male dusky antechinus, an Australian marsupial. Sleep 2022; 45:6585950. [PMID: 35567787 PMCID: PMC9366648 DOI: 10.1093/sleep/zsac114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 05/05/2022] [Indexed: 11/14/2022] Open
Abstract
Abstract
Study Objectives
In this study, we (1) describe sleep behavior and architecture, and (2) explore how sleep is regulated in dusky antechinus (Antechinus swainsonii), a small insectivorous marsupial. Our aim is to provide the first investigation into sleep homeostasis in a marsupial.
Methods
Wild-caught male dusky antechinus (n = 4) were individually housed in large indoor cages under a natural photoperiod of 10.5 h light/13.5 h dark. Continuous recordings of EEG, EMG, and tri-axial accelerometry were performed under baseline conditions and following 4-h of extended wakefulness.
Results
Antechinus engage in SWS and REM sleep. Some aspects of these states are mammal-like, including a high amount (23%) of REM sleep, but other features are reminiscent of birds, notably, hundreds of short sleep episodes (SWS mean: 34 s; REM sleep: 10 s). Antechinus are cathemeral and sleep equally during the night and day. Immediately after the sleep deprivation ended, the animals engaged in more SWS, longer SWS episodes, and greater SWS SWA. The animals did not recover lost REM sleep.
Conclusions
Sleep architecture in dusky antechinus was broadly similar to that observed in eutherian and marsupial mammals, but with interesting peculiarities. We also provided the first evidence of SWS homeostasis in a marsupial mammal.
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Affiliation(s)
- Erika Zaid
- School of Agriculture, Biomedicine and Environment, La Trobe University , Melbourne , Australia
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich/ETH Zurich , Zurich , Switzerland
| | - John A Lesku
- School of Agriculture, Biomedicine and Environment, La Trobe University , Melbourne , Australia
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Harding CD, Yovel Y, Peirson SN, Hackett TD, Vyazovskiy VV. Re-examining extreme sleep duration in bats: implications for sleep phylogeny, ecology, and function. Sleep 2022; 45:6547911. [PMID: 35279722 PMCID: PMC9366634 DOI: 10.1093/sleep/zsac064] [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: 11/25/2021] [Revised: 02/17/2022] [Indexed: 11/23/2022] Open
Abstract
Bats, quoted as sleeping for up to 20 h a day, are an often used example of extreme sleep duration amongst mammals. Given that duration has historically been one of the primary metrics featured in comparative studies of sleep, it is important that species specific sleep durations are well founded. Here, we re-examined the evidence for the characterization of bats as extreme sleepers and discuss whether it provides a useful representation of the sleep behavior of Chiroptera. Although there are a wealth of activity data to suggest that the diurnal cycle of bats is dominated by rest, estimates of sleep time generated from electrophysiological analyses suggest considerable interspecific variation, ranging from 83% to a more moderate 61% of the 24 h day spent asleep. Temperature-dependent changes in the duration and electroencephalographic profile of sleep suggest that bats represent a unique model for investigating the relationship between sleep and torpor. Further sources of intra-specific variation in sleep duration, including the impact of artificial laboratory environments and sleep intensity, remain unexplored. Future studies conducted in naturalistic environments, using larger sample sizes and relying on a pre-determined set of defining criteria will undoubtedly provide novel insights into sleep in bats and other species.
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Affiliation(s)
- Christian D Harding
- Department of Physiology Anatomy and Genetics, Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK.,The Kavli Institute for Nanoscience Discovery, Oxford, UK
| | - Yossi Yovel
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Stuart N Peirson
- The Kavli Institute for Nanoscience Discovery, Oxford, UK.,Nuffield Department of Clinical Neurosciences, Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK
| | | | - Vladyslav V Vyazovskiy
- Department of Physiology Anatomy and Genetics, Sir Jules Thorn Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, UK.,The Kavli Institute for Nanoscience Discovery, Oxford, UK
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Gübert J, Hahn-Klimroth M, Dierkes PW. BOVIDS: A deep learning-based software package for pose estimation to evaluate nightly behavior and its application to common elands ( Tragelaphus oryx) in zoos. Ecol Evol 2022; 12:e8701. [PMID: 35342615 PMCID: PMC8928879 DOI: 10.1002/ece3.8701] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 02/13/2022] [Accepted: 02/17/2022] [Indexed: 12/29/2022] Open
Abstract
Only a few studies on the nocturnal behavior of African ungulates exist so far, with mostly small sample sizes. For a comprehensive understanding of nocturnal behavior, the data basis needs to be expanded. Results obtained by observing zoo animals can provide clues for the study of wild animals and furthermore contribute to a better understanding of animal welfare and better husbandry conditions in zoos. The current contribution reduces the lack of data in two ways. First, we present a stand-alone open-source software package based on deep learning techniques, named Behavioral Observations by Videos and Images using Deep-Learning Software (BOVIDS). It can be used to identify ungulates in their enclosure and to determine the three behavioral poses "Standing," "Lying-head up," and "Lying-head down" on 11,411 h of video material with an accuracy of 99.4%. Second, BOVIDS is used to conduct a case study on 25 common elands (Tragelaphus oryx) out of 5 EAZA zoos with a total of 822 nights, yielding the first detailed description of the nightly behavior of common elands. Our results indicate that age and sex are influencing factors on the nocturnal activity budget, the length of behavioral phases as well as the number of phases per behavioral state during the night while the keeping zoo has no significant influence. It is found that males spend more time in REM sleep posture than females while young animals spend more time in this position than adult ones. Finally, the results suggest a rhythm between the Standing and Lying phases among common elands that opens future research directions.
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Affiliation(s)
- Jennifer Gübert
- Faculty of Biological Sciences Bioscience Education and Zoo Biology Goethe University Frankfurt Germany
| | | | - Paul W Dierkes
- Faculty of Biological Sciences Bioscience Education and Zoo Biology Goethe University Frankfurt Germany
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