j. F. EISENBERG The Tenrecs: A Study 'EDWIN GOULD in Mammalian Behavior and Evolution SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • 1969 NUMBER 27 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY NUMBER 27 j. F. Eisenberg The Tenrecs: A Study and Edwin Gould {n Mammalian Behavior and Evolution SMITHSONIAN INSTITUTION PRESS CITY OF WASHINGTON I97O SERIAL PUBLICATIONS OF THE SMITHSONIAN INSTITUTION The emphasis upon publications as a means of diffusing knowledge was expressed by the first Secretary of the Smithsonian Institution. In his formal plan for the Insti- tution, Joseph Henry articulated a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge not strictly professional." 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UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1970 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price $3.25 Contents Page Introduction 1 Itineraries and Field Methods in Madagascar 4 Captive Studies 6 The Island of Madagascar and its Mammalian Fauna 8 Madagascar: Historical Review and Current Status of Habitats 8 The Mammalian Fauna of Madagascar 10 The Rainforest and Plateau 15 The Madagascar Fauna in Perspective 16 Some Negative Influences on the Numbers and Distribution of the Tenrecidae 17 Predators and Competitors of the Tenrecidae 17 Competitors 17 Predators 17 Snakes 17 Raptorial Birds 18 Native Carnivores 18 Domestic Dogs and Cats ' 22 Summary of Predation Studies 22 Parasites and Diseases of the Tenrecidae 22 Disease Problems in the Captive Colony 23 A Survey of the Oryzorictinae 24 The Aquatic Syndrome—Limnogale Major, 1896a 24 Sex Criteria 24 Distribution and Abundance 24 Habitat and Home 24 Foods 25 Reproduction 25 Notes Concerning Behavior 25 The Fossorial Syndrome—Oryzorictes A. Grandidier, 1870 26 Distribution 27 Habitat : 27 The Genus Geogale 27 The Genus Microgale Thomas, 1883 28 Sympatric and Allopatric Considerations 30 Microgale dobsoni 31 Physical Description 31 Distribution and Habitat 31 The Annual Cycle, Reproduction, and Thermoregulation 33 Feeding Habits 34 Ethological Studies .• 34 General Maintenance Behavior 34 Social Behavior 36 Discussion 39 Parental Care Behavior 43 Ontogeny of Behavior 43 Social Organization 43 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY Page Other Species of Microgale 44 Microgale ta.laz.aci 44 Physical Description 44 Distribution and Habitat 44 The Annual Cycle, Reproduction, and Thermoregulation 45 Feeding Habits 45 Ethological Studies 45 General Maintenance Behavior 45 Social Behavior 46 Microgale cowani 47 Physical Description 47 Distribution and Habitat 47 General Remarks on Behavior 48 Setifer setosus 49 An Introduction to the Tenrecinae 49 Setifer (= Ericulus) setosus (Froriep, 1806) 49 Physical Description 49 Distribution and Habitat 50 Burrows 50 The Annual Cycle and Reproduction 51 Activity and Thermoregulation 51 Feeding Habits 52 Ethological Studies 52 General Maintenance Behavior 52 Social Behavior 54 Parental Care Behavior 56 Ontogeny of Behavior 57 Social Organization 57 Echinops telfairi (Martin, 1838) 59 Physical Description 59 Distribution and Habitat 59 Activity and Thermoregulation 59 The Annual Cycle and Reproduction 59 Feeding Habits 60 Ethological Studies 60 General Maintenance Behavior 60 Social Behavior 61 Parental Care 62 Ontogeny of Behavior 64 Social Organization 65 Tenrec (= Centetes) ecaudatus (Lacepede, 1799) 66 Physical Description 66 Distribution and Habitat 66 Burrows 67 Activity Patterns 68 The Annual Cycle, Thermoregulation, and Reproduction 68 Feeding Habits 69 Ethological Studies 69 General Maintenance Behavior 69 Social Behavior 71 Parental Care 73 Ontogeny of Behavior 73 Stridulation and Communication 74 Social Organization 77 NUMBER 2 7 Page The Ecology of Hemicentetes (Mivart, 1871) 78 Introduction 78 H. nigriceps—General Ecology 79 Physical Description 79 Distribution and Habitat 80 Burrows and Microhabitat 81 Activity and Thermoregulation 81 The Annual Cycle and Reproduction 82 Feeding and Food Intake 83 Earthworm Behavior and Ecology 84 Food Consumption 84 H. semispinos is—General Ecology 85 Physical Description 85 Distribution and Habitat 85 Burrows and Microhabitat 85 Activity and Thermoregulation 87 The Annual Cycle and Reproduction 88 Feeding and Food Intake 89 The Ethology of Hemicentetes 90 General Maintenance Behavior 90 Social Behavior 94 Parental Care Behavior 97 Ontogeny of Behavior 97 Social Organization 98 Stridulation in Hemicentetes 102 The Phenomenon of Stridulation 102 Introduction 102 The Motivational Basis for Stridulation 102 Light Intensity and Crest Erection 103 Arousal and Stridulation 105 Sound Intensity and Crest Erection 105 Stridulation and Circumstances of Occurrence 106 The Playback Experiments 108 Introduction 108 Preliminary Tests 108 The Orientation Test 110 The Role of the Mother's Stridulation in Nature Ill Other Functions of Stridulation 112 Comparisons and Extensions 116 Evolutionary Trends Among the Tenrecidae 116 A Comparison of Behavior Categories 117 The Insectivora: A Consideration of Evolutionary Limits 119 Configurations in Space and Time 121 Literature Cited 124 Appendix A: Collecting Localities and Study Areas 127 Appendix B: List of Specimen Sightings and Collections 128 Appendix C: Thermoregulation Techniques and Criteria 128 Appendix D: Encounter Techniques and Open Field Tests 129 Appendix E: Speed Tests 130 Appendix F: Activity Measurements 130 Appendix G: Predator Odor Tests 130 Appendix H: Sound Recording and Playback Techniques 130 Appendix I: Care and Maintenance of Captive Tenrecidae 132 Index 135 ABSTRACT Eisenberg, J. F., and Edwin Gould. The Tenrecs: A Study in Mammalian Behavior and Evolution. Smithsonian Contributions to Zoology, 27: 1-137. 1970.—Tenrecs are found only on the island of Madagascar. The biology of the Tenrecidae is described by field and laboratory studies that focused on comparisons of social behavior and communication in several species. Detailed observations on the behavior of Echinops, Setifcr, Tenrec, Hemicentetes, and Microgale are related to ecological adaptations of each genus. Experimental manipulations of Hemicentetes revealed that a sound-producing organ composed of dorsal quills functions to coordinate the movements of mother and infants. Evolutionary trends in structure and behavior of the tenrecs are discussed. The mammalian feeding niches of Panama and Madagascar are compared. J. F. Eisenberg The Tenrecs: A Study and Edwin Gould in Mammalian Behavior and Evolution Introduction The tenrecs are a diversified family of insectivorous many tenrec species to compete successfully with viver- mammals confined to the island of Madagascar. In- rid carnivores and, thus, they prevail not as the dull- cluding some 25 named forms divisible into 7 genera, colored, small, cryptic mammals recognized as insec- these animals offer a unique opportunity for the study tivores by naturalists in the temperate zone, but in of behavioral evolution. They occur within a wide many cases as large or conspicuously colored mammals range of habitats and have adapted to aquatic, fos- (see Figures 1 and 2). sorial, and semi-arboreal ecological niches. Nowhere In 1963 Edwin Gould went to Madagascar to study else have the insectivores displayed such a range of the echolocating ability of tenrecoid insectivores and, adaptation within such a limited geographical region as a result, became involved with the total biology of Although the tenrecs have exhibited a remarkable these animals. On his return, he brought many captive adaptive radiation on Madagascar, this has been ac- specimens with him and joined forces with John F. complished with few major alterations in basic body Eisenberg, who had initiated captive studies on the plan; thus, we have in essence a mammal with many behavior of selected species of hedgehogs, shrews, and conservative physiological and morphological features the hedgehog tenrec, Setifer. including: an unstable thermoregulation, reduced vis- In 1966 and 1967, Eisenberg and Gould returned to ual capacity with concomitant dependence