Andrews University Digital Commons @ Andrews University Master's Theses Graduate Research 2020 The Use of Multiple Sensory Modalities by the Antillean Manatee (Trichechus Manatus Manatus) To Locate Food in Their Natural Environments Amanda Marie Moore Andrews University, [email protected] Follow this and additional works at: https://digitalcommons.andrews.edu/theses Part of the Biology Commons Recommended Citation Moore, Amanda Marie, "The Use of Multiple Sensory Modalities by the Antillean Manatee (Trichechus Manatus Manatus) To Locate Food in Their Natural Environments" (2020). Master's Theses. 183. https://digitalcommons.andrews.edu/theses/183 This Thesis is brought to you for free and open access by the Graduate Research at Digital Commons @ Andrews University. It has been accepted for inclusion in Master's Theses by an authorized administrator of Digital Commons @ Andrews University. For more information, please contact [email protected]. ABSTRACT THE USE OF MULTIPLE SENSORY MODALITIES BY THE ANTILLEAN MANATEE (TRICHECHUS MANATUS MANATUS) TO LOCATE FOOD IN THEIR NATURAL ENVIRONMENTS By AMANDA MOORE Chair: Daniel Gonzalez-Socoloske, Ph.D. ABSTRACT OF GRADUATE STUDENT RESEARCH Thesis Andrews University College of Arts and Sciences Title: THE USE OF MULTIPLE SENSORY MODALITIES BY THE ANTILLEAN MANATEE (TRICHECHUS MANATUS MANATUS) TO LOCATE FOOD IN THEIR NATURAL ENVIRONMENTS Name of researcher: Amanda Marie Moore Name and degree of faculty chair: Daniel Gonzalez-Socoloske, Ph.D. Date completed: July 2020 Manatees are herbivorous aquatic mammals found in the coastal and inland waters of the Atlantic Ocean. All three manatee species are currently listed as vulnerable on the IUCN red list and there still remains much unknown about their ecology. It is currently unknown what sensory modalities manatees use to locate their food in the wild. A literature review of the Paenungulata clade (sirenians, proboscideans, and hyracoideans) was conducted in order to compare and contrast what is known about the sensory modalities of the clade, to better understand the sensory modalities of manatees, particularly the ones they use to locate their food. Manatees have a higher frequency range for hearing than elephants, who have the best low-frequency hearing range known to mammals; hearing range of hyrax is unknown. All members of Paenungulata have vibrissae assisting in tactile abilities and potentially compensate for other senses such as hearing or vision. The ability to smell in manatees and hyrax is unknown, but elephants have been found to have an excellent sense of smell. Manatees, elephants, and hyrax have dichromatic vision. A preliminary experiment was designed to test manatee feeding modalities in the wild. The objectives of this study were to determine if the proposed methodology, modified for an aquatic environment from Renda & Roux (2017), was capable of testing manatee sensory use by limiting the sensory cues provided. Sensory modalities used in locating food were tested in two ways: when they know where the food is located, within a short distance, and when the food is placed randomly throughout their habitat, at long distances. In this study, we were able to show that the experimental design works, and provide preliminary data. In the short distance dichotomous choice trials, the percent of correct choices were 67% for the chemoreception + vision, 60% for chemoreception only, and 60% for vision only, with 50% being the rate of chance. For long distance experiments, the mean minimum time in hours it took manatees to consume the food placed randomly along their habitat of San San-Pond Sak River, Panama was 12.0 hours for chemoreception + vision, more than 22 hours for chemoreception only, and 6.89 hours for the control (no box). Due to the small sample size, no definitive conclusion could be made as to which sensory modality manatees use to find food, but our results support the idea that manatees use multiple modalities, chemoreception + vision, to locate food. Additional trials are needed in order to perform statistical analysis on the data. Andrews University College of Arts and Sciences THE USE OF MULTIPLE SENSORY MODALITIES BY THE ANTILLEAN MANATEE (TRICHECHUS MANATUS MANATUS) TO LOCATE FOOD IN THEIR NATURAL ENVIRONMENTS A Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science by Amanda Marie Moore July 2020 ©Copyright by Amanda M. Moore 2020 All Rights Reserved THE USE OF MULTIPLE SENSORY MODALITIES BY THE ANTILLEAN MANATEE (TRICHECHUS MANATUS MANATUS) TO LOCATE FOOD IN THEIR NATURAL ENVIRONMENTS A thesis presented in partial fulfillment of the requirements for the degree Master of Science by Amanda Marie Moore APPROVAL BY THE COMMITTEE: _______________________________ Daniel Gonzalez-Socoloske, Ph.D., Chair __________________________________ Benjamin Navia, Ph.D. __________________________________ June 18, 2020 Robert E. Zdor, Ph.D. Date approved vii TABLE OF CONTENTS LIST OF FIGURES …………………………………………………………………………… x LIST OF TABLES ……………………………………………………………………………. xi LIST OF ABBREVIATIONS ………………………………………………………………… xii ACKNOWLEDGMENTS ……………………………………………………………………. xiii CHAPTERS 1. INTRODUCTION ………………………………………………………………… 1 2. REVIEW OF SENSORY MODALITIES OF THE EXTANT PAENGULATA CLADE……………………………………………………………………………….. 5 a. BRIEF HISTORY OF EVOLUTIONARY DIVERGENCE OF PAENUNGULATA…………………………………………………………. 5 b. HEARING………………………………………………………………… 6 i. Hearing Anatomy of Sirenians……………………………………. 6 ii. Hearing Physiology of Sirenians…………………………………. 9 iii. Hearing Anatomy of Proboscidea……………………………….. 11 iv. Hearing Physiology of Proboscidea……………………………... 12 v. Hearing Anatomy & Physiology of Hyracoidea…………………. 13 c. TOUCH…………………………………………………………………… 13 i. Tactile Anatomy of Sirenia……………………………………….. 13 ii. Tactile Physiology of Sirenia…………………………………….. 18 iii. Tactile Anatomy & Physiology of Proboscidea…………………. 20 iv. Tactile Anatomy & Physiology of Hyracoidea………………….. 22 d. CHEMORECEPTION (TASTE AND SMELL)………………………….. 23 i. Chemoreception Anatomy & Physiology of Sirenia……………… 23 ii. Chemoreception Anatomy & Physiology of Proboscidea………... 26 iii. Chemoreception Anatomy & Physiology of Hyracoidea………... 29 e. VISION……………………………………………………………………. 30 i. Visual Anatomy of Sirenians……………………………………… 30 viii ii. Visual Physiology of Sirenians…………………………………… 31 iii. Visual Anatomy & Physiology of Proboscidea………………….. 32 iv. Visual Anatomy & Physiology of Hyracoidea…………………... 33 f. VESTIBULAR (BALANCE AND SPATIAL ORIENTATION)…………. 33 i. Vestibular Anatomy & Physiology of Sirenia…………………….. 33 ii. Vestibular Anatomy & Physiology of Proboscidea and Hyracoidea……………………………………………………….. 34 g. CONCLUSION……………………………………………………………. 34 3. PRELIMINARY ASSESSMENT FOR HOW MANATEES (TRICHECHUS MANATUS MANATUS) USE SENSORY MODALITIES TO FIND FOOD…………………..…. 39 a. INTRODUCTION…………………………………………………………. 39 b. METHODS………………………………………………………………… 43 i. Study Site…………………………………………………………... 43 ii. Design……………………………………………………………... 44 iii. Trials……………………………………………………………... 46 c. RESULTS………………………………………………………………….. 49 d. DISCUSSION……………………………………………………………… 54 i. Short Distance Dichotomous Choice Trials: Chemoreception + Vision………………………………………….. 59 ii. Short Distance Dichotomous Choice Trials: Chemoreception Only……………………………………………………………….. 59 iii. Short Distance Dichotomous Choice Trials: Vision Only……………………………………………………………….. 60 iv. Long Distance Trials……………………………………………… 61 4. CONCLUSION………………………………………………..……………………. 64 REFERENCES ………………………………………………………………………………… 69 APPENDIX ……………………………………………………………………………………. 88 A. Right/Left Preference Towards Boxes Chosen Versus Where Food was placed…. 88 B. Long Distance Experiments Raw Data……………………………………………. 89 C. Still Shots of Manatees Participating in Experiments……………………………... 91 ix LIST OF FIGURES 1. Manatee Perioral Bristle Fields……………………………………………… 15 2. Box Design………………………………………………………………………….. 46 3. Constructed Boxes…………………………………………………………………... 47 4. Choice Trial Set-Up…………………………………………………………………. 50 5. Choice Trial Results…………………………………………………………………. 52 6. Long Distance Experimental Results………………………………………………… 53 7. Manatee Eating Banana Leaves……………………………………………………… 54 x LIST OF TABLES 1. Summary of Sensory Modalities Between the Members of the Paenungulata Clade…… 38 2. Box Design and Sensory Cues…………………………………………………………... 45 xi LIST OF ABBREVIATIONS ABR Auditory Brainstem Response AEP Auditory Evoked Potential dB Decibel FSC Follicle Sinus Complex GPS Global Positioning System IACUC Institutional Animal Care and Use Committee IUCN International Union for Conservation of Nature kHz Kilohertz re 1 µPa Reference Pressure in Water TNT Trinitrotoluene UV Ultraviolet xii ACKNOWLEDGEMENTS I would like to thank my advisor, Dr. Daniel Gonzalez-Socoloske, for his mentorship during my graduate program. I am grateful for the opportunities he provided and time and sacrifices he made for research to be conducted in Panama, which included the need for him to translate for me in-country and teaching me the skills and flexibility of conducting field research. I appreciate his patience and dedication to conducting this research and helping me complete my thesis. I would like to thank Dr. Benjamin Navia and Dr. Robert Zdor for their time and contributions to the completion of my thesis. I would additionally like to thank the faculty of the Department of Biology at Andrews University for the opportunity to study here and the support they have provided while completing my master’s degree. A special thanks to Sixto Herrera and Juan McDonald