Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2017 How do mammals buffer environmental seasonality? The role of brain size, body fat and allomaternal care in dealing with energy shortage Heldstab, Sandra Andrea Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-144968 Dissertation Published Version Originally published at: Heldstab, Sandra Andrea. How do mammals buffer environmental seasonality? The role of brain size, body fat and allomaternal care in dealing with energy shortage. 2017, University of Zurich, Faculty of Science. How Do Mammals Buffer Environmental Seasonality? The Role of Brain Size, Body Fat and Allomaternal Care in Dealing with Energy Shortage Dissertation zur Erlangung der naturwissenschaftlichen Doktorwürde (Dr. sc. nat.) vorgelegt der Mathematisch-naturwissenschaftlichen Fakultät der Universität Zürich von Sandra Andrea Heldstab von Saas GR Promotionskommission Prof. Dr. Carel van Schaik (Vorsitz) PD Dr. Karin Isler (Leitung der Dissertation) Prof. Dr. med. vet. Marcus Clauss Zürich, 2017 “There is a time for everything, and a season for every activity under the heavens…” (Ecclesiastes 3) Table of Contents i Table of Contents Summary ..................................................................................................................................... 1 Zusammenfassung........................................................................................................................ 3 Chapter 1: General introduction ................................................................................................... 7 Humans have a unique combination of traits ............................................................................ 7 What is seasonality? ................................................................................................................... 8 Impact of seasonality on mammals .......................................................................................... 10 How do mammals cope with seasonal food scarcity? ............................................................. 12 Cognitive buffering ................................................................................................................... 12 Cognitive buffering in birds ......................................................................................... 12 Cognitive buffering in mammals .................................................................................. 14 Cognitive buffering comes at a cost ............................................................................ 15 Physiological buffering ............................................................................................................. 16 Body fat storage ........................................................................................................... 16 Hibernation and torpor ................................................................................................ 18 Decreasing resting metabolic rate ............................................................................... 20 Migration and habitat switching.................................................................................. 20 Seasonal breeding........................................................................................................ 22 Care buffering ........................................................................................................................... 22 Content of this dissertation ...................................................................................................... 24 Chapter 2: Manipulation complexity in primates coevolved with brain size and terrestriality ................................................................................................................. 25 Chapter 3: Being fat and smart: A comparative analysis of the fat-brain trade-off in mammals ................................................................................................................. 25 Chapter 4: Getting fat or getting help? How female mammals cope with energetic constraints on reproduction ........................................................................................ 26 References ................................................................................................................................ 27 Chapter 2: Manipulation complexity in primates coevolved with brain size and terrestriality ....... 43 Abstract .................................................................................................................................... 43 Introduction .............................................................................................................................. 44 Material and methods .............................................................................................................. 46 Data collection ............................................................................................................. 46 ii Complexity levels ........................................................................................................ 47 Cognitive test performance and brain size ................................................................. 48 Diet quality and terrestriality ...................................................................................... 49 Statistical analyses ...................................................................................................... 49 Ethical statement animals........................................................................................... 50 Ethical statement humans .......................................................................................... 50 Results ...................................................................................................................................... 51 Discussion ................................................................................................................................ 54 Complexity of manipulations ...................................................................................... 55 Ecology ........................................................................................................................ 56 Cognitive abilities ........................................................................................................ 56 Terrestriality ................................................................................................................ 57 The human case .......................................................................................................... 58 Acknowledgements ................................................................................................................. 59 Supplementary material .......................................................................................................... 60 Supplementary material and methods ....................................................................... 60 Specific brain regions (neocortex and cerebellum) ..................................... 60 Social complexity ......................................................................................... 60 Figure S1. Phylogenetic tree used for the analyses..................................... 61 Supplementary results ................................................................................................ 63 Supplementary results for the correlates of manipulation complexity ...... 63 Results showing that brain size is related to cognitive abilities in our primate sample ............................................................................................ 67 Results of the highest manipulation complexity score ever reached over all bouts ............................................................................................... 67 Results and discussion for the relationship between manipulation complexity relative neocortex and cerebellum size .................................... 68 Results and discussion for a potential confounding effect of social complexity ......................................................................................... 69 Results of an alternative coding system of diet categories related to demands on manipulative skills .................................................................. 70 Results using an alternative phylogenetic tree ........................................... 71 Statistical assumption checks for phylogenetic generalized least-squares 72 Notes on the number of observation bouts ................................................ 73 Table of Contents iii References ................................................................................................................................ 74 Dataset...................................................................................................................................... 79 List of species and data used for this study ................................................................. 79 Chapter 3: Being fat and smart: A comparative analysis of the fat-brain trade-off in mammals ..... 83 Abstract .................................................................................................................................... 83 Introduction .............................................................................................................................