- Macedonian Ecological Society - Herpetology Group
- Macquarie University
- Macquarie University [Sydney]
- Mairie des Anses d’Arlet
- Maison de la Nature et de la Réserve
- Maison de l'estuaire de la Seine
- MAISON DE L'ESTUAIRE LE HAVRE
- Maison des Sciences Humaines de Champagne-Ardenne
- Majella National Park - Parco Nazionale della Majella
- Maladies infectieuses et vecteurs : écologie, génétique, évolution et contrôle
- Malaysia Institute of Oceanography
- Mammal Research Institute
- Manaaki Whenua – Landcare Research [Lincoln]
- MARE – Marine and Environmental Sciences Centre
- Marine and environmental research centre - IMAR-CMA (Coimbra, Portugal)
- Marine and Environmental Sciences Center [Portugal]
- Marine and Environmental Sciences Centre
- Marine and Environmental Sciences Centre [Portugal]
- Marine Apex Predator Research Unit (MAPRU) [Port Elizabeth, South Africa]
- MARine Biodiversity Exploitation and Conservation
- MARine Biodiversity Exploitation and Conservation - MARBEC
- MARine Biodiversity Exploitation and Conservation - Station Ifremer Palavas
- Marine Biological Association
- Marine Biology and Ecology Research Centre
- Marine Biology & Ecology Research Centre
- Marine Biology Lab
- Marine Biology Laboratory
- Marine Geospatial Ecology Laboratory [USA]
- Marine Mammal and Turtle Division
- Marine Mammal Institute
- Marine Mammal Research Unit
- Marine Megafauna Conservation Organisation
- Marine Renewable Energy Ireland
- Martin-Luther-Universität Halle Wittenberg
- Masaryk University [Brno]
- Massachusetts Division of Fisheries and Wildlife
- Massey University
- Materials and Chemistry
- Mauritian Wildlife Foundation
- Mauzac
- Max-Planck-Gesellschaft
- Max Planck Institute for Marine Microbiology
- Max Planck Institute for Ornithology
- Max Planck Institute of Animal Behavior
- McGill University = Université McGill [Montréal, Canada]
- Mécanismes adaptatifs : des organismes aux communautés
- Mécanismes Adaptatifs et Evolution
- Médicaments et Technologies pour la Santé
- Med Univ Silesia
- Meiji Institute for Advanced Study of Mathematical Sciences
- Meiji University [Tokyo]
- Meise Botanic Garden [Belgium]
- Melbourne Law School [Melbourne]
- Memorial Univerisity of Newfoundland and Labrador
- Memorial University
- Memorial University, Canada
- Memorial University of Newfoundland = Université Memorial de Terre-Neuve [St. John's, Canada]
- Météo-France
- Migratory Bird Center [DC, USA]
- Milieux aquatiques, écologie et pollutions
- Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols
- Milner Centre for Evolution
- Minerva Foundation Institute for Medical Research
- Mines Paris - PSL (École nationale supérieure des mines de Paris)
- Ministère de l'économie et des finances
- Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche
- Ministère de l'Environnement et du Cadre de vie
- Ministry of Natural Resources of China
- MIRA Aflokkat [Ajaccio]
- Missouri Botanical Garden
- Modèles Insectes de l'Immunité Innée
- Molécules de Communication et Adaptation des Micro-organismes
- Monash university
- Monash University [Australia]
- Monash University [Clayton]
- Monash University in Melbourne, Australia
- Monash University [Melbourne]
- Monash University [Victoria, Australia]
- Monmouth University
- Monterrey Bay Aquarium[USA]
- Morphodynamique Continentale et Côtière
- Moss Landing Marine Laboratories [CA, USA]
- Moss Landing Marine Labs at San Jose State University [USA]
- Mountain Agriculture Research Unit
- Movement Ecology Laboratory [ISRAEL]
- MTA Centre for Ecological Research
- Muğla Sıtkı Koçman Üniversitesi [Türkiye Cumhuriyetı] = Muğla Sıtkı Koçman University [Türkiye] = Université Sıtkı Koçman de Muğla [Turquie]
- Murmansk Marine Biological Institute
- Murmansk Marine Biological [Russia]
- Museo de Ciencias Naturales de Alava
- Museo Nacional de Ciencias Naturales [Madrid]
- Museo Nacional de Historia Natural
- Muséum national d'Histoire naturelle
- Museum of New Zealand Te Papa Tongarewa
- Museu Nacl Hist Nat