What was before suction cups?

So lizards, insects, spiders, and many other critters have the ability to climb walls without manmade handholds. Some people attribute this as having little suction cups attached to the end of their toes. What did people attribute it to before suction cups were invented? Did they actually have the right theory about how the hairs/skin interact on a molecular level with the molecules in the wall and then threw that idea out the window when suction cups were invented? Maybe they said that these creepy crawly creatures had tar or glue or syrup on their feet. Could you imagine syrup on your feet? nice and slimy.