1 2 3 Electronic supplement References for the reported social organization identified in our primary literature research, compared to the social organization provided by Lukas & CluttonBrock (2013) [1]. Numbers refer to the numbers of studies reporting the form of social organization. BS: breeding season; NBS: non-breeding season. Species Lukas &Clutton-Brock Solitary Pair One male several females Multi-males Multi-females Multi malemulti female References Crocidura leucodon Solitary Crocidura russula Solitary 1 Crocidura shantungensis Solitary 1 Cryptotis parva Solitary Neomys fodiens Solitary 1 [7] Sorex araneus Solitary 2 [8, 9] Sorex cinereus Solitary Sorex coronatus Solitary Sorex ornatus Solitary Sorex unguiculatus Solitary 1 Suncus varilla Solitary 1 1 Galemys pyrenaicus Solitary 3 3 Talpa europaea Solitary 1 [17] Talpa romana Solitary 2 [18, 19] Urotrichus talpoides Solitary 1 (BS) Erinaceus europaeus Solitary 1 Soricidae (shrews) 1 (BS) 2 (BS) 1 (NBS) 2 (NBS) 1 (NBS) 1 (NBS) [3, 4] [5] 1 2 (BS) 1 (NBS) [2] 1 (BS) [6] [10, 11] [7] 1 (NBS) 1 (BS) [12] [13] [14] Talpidae (moles) 1 1 (NBS) 1 [15-17] [20] Erinaceidae (hedgehogs and gymnures) [21] 4 5 6 1 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 References 1. Lukas D., Clutton-Brock T.H. 2013 The Evolution of Social Monogamy in Mammals. Science 341(6145), 526-530. (doi:10.1126/science.1238677). 2. Simeonovska-Nikolova D.M. 2004 Seasonal changes in social behaviour and spatial structure of Crocidura leucodon in north-western Bulgaria. Acta Theriol 49, 167-179. 3. Cantoni D., Vogel P. 1989 Social organization and mating system of free-ranging, greater white-toothed shrews, Crocidura russula. Anim Behav 38, 205-214. 4. Ricci J.C., Vogel P. 1984 Nouvelle Méthode D’étude En Nature Des Relations Spatiales et Sociales Chez Crocidura Russula (Mammalia, Soricidae). Mammalia 48, 281286. 5. Lin T.T., You E.M., Lin Y.K. 2009 Social and genetic mating systems of the Asian lesser white-toothed shrew, Crocidura shantungensis, in Taiwan. J Mammal 90(6), 13701380. (doi:10.1644/08-mamm-a-346r1.1). 6. McCarley W.H. 1959 An unusually large nest of Cryptotis parva. J Mammal 40, 243. 7. Cantoni D. 1993 Social and spatial organizsation of free-ranging shrews, Sorex coronatus and Neomys fodiens (Insectivora, Mammalia). Animal Behaviour 45(5), 975995. (doi:10.1006/anbe.1993.1116). 8. Stockley P., Searle J.B., Macdonald D.W., Jones C.S. 1994 Alternative reproductive tactics in male common shrews: relationships between mate-searching behavior, sperm production, and reproductive success as revealed by DNA fingerprinting. Behav Ecol Sociobiol 34(1), 71-78. 9. Buckner C.H. 1969 Some aspects of the population ecology of the common shrew, Sorex araneus, near Oxford, England. J Mammal 50, 326-332. 10. Maier T.J., Doyle K.L. 2006 Aggregations of masked shrews (Sorex cinereus): density-related mating behavior? Mammalia 70(1-2), 86-89. (doi:10.1515/mamm.2006.015). 11. Vispo C.R. 1988 An observation of a wild group of masked shrews, Sorex cinereus. Can Field-Nat 102(4), 731-733. 12. Hays W.S.T., Lidicker W.Z. 2000 Winter aggregations, Dehnel effect, and habitat relations in the Suisun shrew Sorex ornatus sinuosus. Acta Theriol 45, 433-442. 13. Inoue T. 1991 Sex differences in spatial distribution of the big-clawed shrew Sorex unguiculatus. Acta Theriol 36(3-4), 229-237. 14. Lynch C.D. 1991 Population dynamics in the lesser dwarf shrew, Suncus varilla (Mammalia: Soricidae). Navorsinge van die Nasionale Museum Bloemfontein 7, 465-473. 15. Melero Y., Aymerich P., Luque-Larena J.J., Gosalbez J. 2012 New insights into social and space use behaviour of the endangered Pyrenean desman (Galemys pyrenaicus). Eur J Wildl Res 58(1), 185-193. (doi:10.1007/s10344-011-0561-7). 16. Stone R.D. 1987 The social ecology of the Pyrenean desman (Gelemys pyrenaicus) (Insectivora, Talpidae), as revealed by radiotelemetry. Journal of Zoology 212, 117-129. 17. Stone R.D., Gorman M.L. 1985 Social organization of the European mole (Talpa europaea) and the Pyrenean desman (Galemys pyrenaicus). Mammal Rev 15(1), 35-42. (doi:10.1111/j.1365-2907.1985.tb00385.x). 18. Loy A., Beolchini F., Martullo S., Capanna E. 1994 Territorial behavior of Talpa romana in an olive grove habitat in central Italy. Boll Zool 61(3), 207-211. 19. Loy A., Dupre E., Capanna E. 1994 Territorial behavior in Talpa romana, a fosserial insectivore from south-central Italy. J Mammal 75(2), 529-535. (doi:10.2307/1382577). 2 54 55 56 57 58 59 60 20. Ishii N. 1993 Size and distribution of home ranges of the Japanese shrew-mole Urotrichus talpoides. J Mamm Soc Japan 18, 87-98. 21. Haigh A., O'Riordan R.M., Butler F. 2012 Nesting behaviour and seasonal body mass changes in a rural Irish population of the Western hedgehog (Erinaceus europaeus). Acta Theriol 57(4), 321-331. (doi:10.1007/s13364-012-0080-2). 3