A gecko's foot holds itself up with molecular forces, not glue or suction

Each gecko toe carries hundreds of thousands of hair-like setae, and every seta splits into hundreds of nanoscale spatulae just 200 nanometres wide. Contact that close triggers van der Waals forces — weak molecular attractions that, multiplied across millions of tips, let the animal cling to glass by one toe. Researchers calculated the setae on a 70-gram gecko could theoretically support 133 kilograms.

— Standard herpetological references; adhesion mechanism established by Kellar Autumn et al., PNAS, 2002, Gecko