It’s 200,000 years ago, and you’re a Neandertal. You want to make a spear but can’t figure out how to get the pointy stone to stick to the wood shaft. According to archaeological evidence, you and your Neandertal pals had a good alternative to superglue: tar. Now, researchers think they know how our distant relatives may have made the sticky substance without any knowledge of fire. The easiest method required nothing more than a roll of birch bark, wood fiber, and smoldering embers, Science News reports. Whether our now-extinct relatives had figured out how to build fires or were merely capitalizing on natural ones remains up for debate.