title: Bat head contains soft magnetic particles: evidence from magnetism.
abstract: Recent behavioral observations have indicated that bats can sense the Earth's magnetic field. To unravel the magnetoreception mechanism, the present study has utilized magnetic measurements on three migratory species (Miniopterus fuliginosus, Chaerephon plicata, and Nyctalus plancyi) and three non-migratory species (Hipposideros armiger, Myotis ricketti, and Rhinolophus ferrumequinum). Room temperature isothermal remanent magnetization acquisition and alternating-field demagnetization showed that the bats' heads contain soft magnetic particles. Statistical analyses indicated that the saturation isothermal remanent magnetization of brains (SIRM(1T_brain)) of migratory species is higher than those of non-migratory species. Furthermore, the SIRM(1T_brain) of migratory bats is greater than their SIRM(1T_skull). Low-temperature magnetic measurements suggested that the magnetic particles are likely magnetite (Fe3O4). This new evidence supports the assumption that some bats use magnetite particles for sensing and orientation in the Earth's magnetic field.
authors.affiliation: Biogeomagnetism Group, Paleomagnetism and Geochronology Laboratory, Key Laboratory of the Earth's Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Lanxiang
authors.initials: L
authors.lastname: Tian
authors.forename: Wei
authors.initials: W
authors.lastname: Lin
authors.forename: Shuyi
authors.initials: S
authors.lastname: Zhang
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Pan
mesh_terms: D025041:Animal Migration; D000818:Animals; D002685:Chiroptera / Q000145:classification / Q000502:physiology*; D052203:Ferrosoferric Oxide / Q000032:analysis; D006257:Head / Q000502:physiology*; D008280:Magnetics; D013696:Temperature
chemical_list: D052203:Ferrosoferric Oxide