Studies have shown that ancient Maya builders used a range of natural materials such as blood, eggs and natural rubber obtained from local trees when preparing mortar. For example, when in 2018 researchers analysed mortar taken from stones at the main pyramid at the Witzinah archaeological site near Yucatán, Mexico, they found traces of saturated fats typical of degraded natural rubber. The researchers believe the Maya masons obtained the rubber from local trees and used it as a binder along with a fine-grained clay to create a durable mortar to bind the stonework together.