Evolution has shaped geckos excellent abilities of adhering and climbing on steep inclines and even on ceilings,and inspired peoples curiosities about their adhesion mechanisms.Its widely believed that its the Van der Waals forces between the substrates and geckos hierarchical setae that geckos use to adhere,however,there still some issues beyond the capacity of Van der Waals force.For example,why there must be a relative sliding between geckos toe and the substrate before they attract each other? Actually,when two objects were brought into contact and even sliding relatively,they may be electrified.Furthermore,the internal impurities and defects of an object may also induce electric fields even its net charge is zero.These phenomena enlighten us a new idea that whether the geckos feet were also electrified during the indispensable sliding and the corresponding charge may also help to adhere? To clarify our conjecture,we carried out two experiments to investigate the trioelectrification of geckos feet and to evaluate the contributions of that.Firstly,we detected the possible electric field and the corresponding potentials around geckos feet through an electrometer.Secondly,we tested the tribo-charge between geckos feet and several materials(Teflon,Cu,silicon rubber and leaves)through a widely used Faraday Cup.When a geckos toe was brought approach to a probe,we got significant voltages and the measured voltages increased as the decrease of the distances.The result indicated that theres an electric field around a geckos toe and foot.Furthermore,we tested the charge of clean materials before and after being brought into friction with geckos feet respectively.The result indicated that the all materials got negative charge while geckos feet got positive charge,which agreed with the tribological sequence.Additionally,geckos feet were charged most(about 20nC)after contact with Teflon compared with the rest materials.Interestingly,a former research found that geckos climb well on Teflon flat than the rest materials,indeed.Our experiments demonstrated that geckos feet can be charged through the triboeletrification.The charge at geckos feet and substrate with opposite polarities will generate attractive forces,which may help gecko to adhere.