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Milne AO, Orton L, Black CH, Jones GC, Sullivan M, Grant RA. California sea lions employ task-specific strategies for active touch sensing. J Exp Biol 2021; 224:273347. [PMID: 34608932 PMCID: PMC8627572 DOI: 10.1242/jeb.243085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/26/2021] [Indexed: 12/03/2022]
Abstract
Active sensing is the process of moving sensors to extract task-specific information. Whisker touch is often referred to as an active sensory system as whiskers are moved with purposeful control. Even though whisker movements are found in many species, it is unknown whether any animal can make task-specific movements with their whiskers. California sea lions (Zalophus californianus) make large, purposeful whisker movements and are capable of performing many whisker-related discrimination tasks. Therefore, California sea lions are an ideal species to explore the active nature of whisker touch sensing. Here, we show that California sea lions can make task-specific whisker movements. California sea lions move their whiskers with large amplitudes around object edges to judge size, make smaller, lateral stroking movements to judge texture and make very small whisker movements during a visual task. These findings, combined with the ease of training mammals and measuring whisker movements, makes whiskers an ideal system for studying mammalian perception, cognition and motor control. Highlighted Article: California sea lions engage in task-specific active touch sensing with their whiskers to discriminate size and differentiate textures, indicating that their whiskers are truly an active sensory system.
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Affiliation(s)
- Alyx O Milne
- Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK.,Events Team, Blackpool Zoo, East Park Drive, Blackpool, FY3 8PP, UK
| | - Llwyd Orton
- Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK
| | | | - Gary C Jones
- Events Team, Blackpool Zoo, East Park Drive, Blackpool, FY3 8PP, UK
| | - Matthew Sullivan
- Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK
| | - Robyn A Grant
- Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK
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Grant RA, Goss VGA. What can whiskers tell us about mammalian evolution, behaviour, and ecology? Mamm Rev 2021. [DOI: 10.1111/mam.12253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Robyn A. Grant
- Department of Natural Sciences Manchester Metropolitan University John Dalton Building, Chester Street ManchesterM1 5GDUK
| | - Victor G. A. Goss
- School of Engineering London South Bank University Borough Road LondonSE1 0AAUK
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Dougill G, Starostin EL, Milne AO, Heijden GHM, Goss VGA, Grant RA. Ecomorphology reveals Euler spiral of mammalian whiskers. J Morphol 2020; 281:1271-1279. [DOI: 10.1002/jmor.21246] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/17/2020] [Accepted: 07/18/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Gary Dougill
- Department of Natural Sciences Manchester Metropolitan University Manchester UK
| | - Eugene L. Starostin
- School of Engineering, London South Bank University London UK
- Department of Civil, Environmental and Geomatic Engineering University College London London UK
| | - Alyx O. Milne
- Department of Natural Sciences Manchester Metropolitan University Manchester UK
| | - Gert H. M. Heijden
- Department of Civil, Environmental and Geomatic Engineering University College London London UK
| | | | - Robyn A. Grant
- Department of Natural Sciences Manchester Metropolitan University Manchester UK
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Pinnipeds orient and control their whiskers: a study on Pacific walrus, California sea lion and Harbor seal. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:441-451. [PMID: 32077991 PMCID: PMC7192888 DOI: 10.1007/s00359-020-01408-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/30/2020] [Accepted: 02/03/2020] [Indexed: 11/10/2022]
Abstract
Whisker touch is an active sensory system. Previous studies in Pinnipeds have adopted relatively stationary tasks to judge tactile sensitivity, which may not accurately promote natural whisker movements and behaviours. This study developed a novel feeding task, termed fish sweeping to encourage whisker movements. Head and whisker movements were tracked from video footage in Harbor seal (Phoca vitulina), California sea lion (Zalophus californianus) and Pacific walrus (Odobenus rosmarus divergens). All species oriented their head towards the moving fish target and moved their whiskers during the task. Some species also engaged in whisker control behaviours, including head-turning asymmetry in the Pacific walrus, and contact-induced asymmetry in the Pacific walrus and California sea lion: behaviours that have only previously been observed in terrestrial mammals. This study confirms that Pinnipeds should be thought of as whisker specialists, and that whisker control (movement and positioning) is an important aspect of touch sensing in these animals, especially in sea lions and walruses. That the California sea lion controls whisker movement in relation to an object, and also had large values of whisker amplitude, spread and asymmetry, suggests that California sea lions are a promising model with which to further explore active touch sensing.
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Muchlinski MN, Wible JR, Corfe I, Sullivan M, Grant RA. Good Vibrations: The Evolution of Whisking in Small Mammals. Anat Rec (Hoboken) 2018; 303:89-99. [PMID: 30332721 DOI: 10.1002/ar.23989] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 01/14/2018] [Indexed: 01/11/2023]
Abstract
While most mammals have whiskers, some tactile specialists-mainly small, nocturnal, and arboreal species-can actively move their whiskers in a symmetrical, cyclic movement called whisking. Whisking enables mammals to rapidly, tactually scan their environment to efficiently guide locomotion and foraging in complex habitats. The muscle architecture that enables whisking is preserved from marsupials to primates, prompting researchers to suggest that a common ancestor might have had moveable whiskers. Studying the evolution of whisker touch sensing is difficult, and we suggest that measuring an aspect of skull morphology that correlates with whisking would enable comparisons between extinct and extant mammals. We find that whisking mammals have larger infraorbital foramen (IOF) areas, which indicates larger infraorbital nerves and an increase in sensory acuity. While this relationship is quite variable and IOF area cannot be used to solely predict the presence of whisking, whisking mammals all have large IOF areas. Generally, this pattern holds true regardless of an animal's substrate preferences or activity patterns. Data from fossil mammals and ancestral character state reconstruction and tracing techniques for extant mammals suggest that whisking is not the ancestral state for therian mammals. Instead, whisking appears to have evolved independently as many as seven times across the clades Marsupialia, Afrosoricida, Eulipotyphla, and Rodentia, with Xenarthra the only placental superordinal clade lacking whisking species. However, the term whisking only captures symmetrical and rhythmic movements of the whiskers, rather than all possible whisker movements, and early mammals may still have had moveable whiskers. Anat Rec, 2018. © 2018 American Association for Anatomy.
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Affiliation(s)
- Magdalena N Muchlinski
- Center for Anatomical Sciences, University of North Texas Health Science Center, Fort Worth, Texas
| | - John R Wible
- Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania
| | - Ian Corfe
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Matthew Sullivan
- Division of Biology and Conservation Ecology, Manchester Metropolitan University, Manchester, UK
| | - Robyn A Grant
- Division of Biology and Conservation Ecology, Manchester Metropolitan University, Manchester, UK
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Turner EC, Sawyer EK, Kaas JH. Optic nerve, superior colliculus, visual thalamus, and primary visual cortex of the northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus). J Comp Neurol 2017; 525:2109-2132. [PMID: 28188622 DOI: 10.1002/cne.24188] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 11/07/2022]
Abstract
The northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus) are members of a diverse clade of carnivorous mammals known as pinnipeds. Pinnipeds are notable for their large, ape-sized brains, yet little is known about their central nervous system. Both the northern elephant seal and California sea lion spend most of their lives at sea, but each also spends time on land to breed and give birth. These unique coastal niches may be reflected in specific evolutionary adaptations to their sensory systems. Here, we report on components of the visual pathway in these two species. We found evidence for two classes of myelinated fibers within the pinniped optic nerve, those with thick myelin sheaths (elephant seal: 9%, sea lion: 7%) and thin myelin sheaths (elephant seal: 91%, sea lion: 93%). In order to investigate the architecture of the lateral geniculate nucleus, superior colliculus, and primary visual cortex, we processed brain sections from seal and sea lion pups for Nissl substance, cytochrome oxidase, and vesicular glutamate transporters. As in other carnivores, the dorsal lateral geniculate nucleus consisted of three main layers, A, A1, and C, while each superior colliculus similarly consisted of seven distinct layers. The sea lion visual cortex is located at the posterior side of cortex between the upper and lower banks of the postlateral sulcus, while the elephant seal visual cortex extends far more anteriorly along the dorsal surface and medial wall. These results are relevant to comparative studies related to the evolution of large brains.
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Affiliation(s)
- Emily C Turner
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
| | - Eva K Sawyer
- Department of Psychology, Vanderbilt University, Nashville, Tennessee.,Department of Bioengineering, University of California, Berkeley, California
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
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Grant RA, Delaunay MG, Haidarliu S. Mystacial Whisker Layout and Musculature in the Guinea Pig (Cavia porcellus): A Social, Diurnal Mammal. Anat Rec (Hoboken) 2016; 300:527-536. [DOI: 10.1002/ar.23504] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/22/2016] [Accepted: 08/24/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Robyn A. Grant
- Conservation, Evolution and Behaviour Research Group, Manchester Metropolitan University; Manchester UK
| | - Mariane G. Delaunay
- Conservation, Evolution and Behaviour Research Group, Manchester Metropolitan University; Manchester UK
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Sawyer EK, Turner EC, Kaas JH. Somatosensory brainstem, thalamus, and cortex of the California sea lion (Zalophus californianus). J Comp Neurol 2016; 524:1957-75. [PMID: 26878587 PMCID: PMC4833517 DOI: 10.1002/cne.23984] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 12/18/2022]
Abstract
Pinnipeds (sea lions, seals, and walruses) are notable for many reasons, including their ape-sized brains, their adaptation to a coastal niche that combines mastery of the sea with strong ties to land, and the remarkable abilities of their trigeminal whisker system. However, little is known about the central nervous system of pinnipeds. Here we report on the somatosensory areas of the nervous system of the California sea lion (Zalophus californianus). Using stains for Nissl, cytochrome oxidase, and vesicular glutamate transporters, we investigated the primary somatosensory areas in the brainstem, thalamus, and cortex in one sea lion pup and the external anatomy of the brain in a second pup. We find that the sea lion's impressive array of whiskers is matched by a large trigeminal representation in the brainstem with well-defined parcellation that resembles the barrelettes found in rodents but scaled upward in size. The dorsal column nuclei are large and distinct. The ventral posterior nucleus of the thalamus has divisions, with a large area for the presumptive head representation. Primary somatosensory cortex is located in the neocortex just anterior to the main vertical fissure, and precisely locating it as we do here is useful for comparing the highly gyrified pinniped cortex with that of other carnivores. To our knowledge this work is the first comprehensive report on the central nervous system areas for any sensory system in a pinniped. The results may be useful both in the veterinary setting and for comparative studies related to brain evolution.
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Affiliation(s)
- Eva K Sawyer
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee, 37240
| | - Emily C Turner
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
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