Chimps Prefer Firm and Stable Beds Made From Ugandan Ironwood

Chimpanzees like humans are very choosy when it comes to beds they sleep in. They prefer firm, stable beds made from Ugandan Ironwood, a new study reveals.

Researchers David Samson from University of Nevada and Kevin Hunt from Indiana University conducted a study at Uganda's Toro-Semiliki Wildlife Reserve to find out if chimps were partial to certain woods and other material for nesting. They found that the chimps prefer the Ugandan Ironwood for its firm, stable and resilient properties to make their bed. 

Chimps are known to build their nests or beds in trees using tree branches. They are very particular about choosing the tree species to sleep in more frequently. But what remained a mystery is a why the chimps select a particular tree.

The latest study solves this mystery and says that it is the physical properties of the tree that influences the chimps' decision.  To confirm this they measured the physical characteristics of wood from some common tree species at the wildlife reserve and measured certain physical characteristics of 326 branches. They basically looked at the stiffness and the bending strength of the branches that belonged to seven tree species that the chimps mostly use for nesting purpose.

Apart from this the researchers also measured the leaf surface area and determined the structure of all the seven species.

Out of the 1,844 nests that they sampled for this study, they saw that the chimps most often turned to Ugandan Ironwood to make their nesting place. Over 73.6 percent of the nests were of Ugandan Ironwood though it accounted for just 9.6 percent of the trees in the study area.

The chimps preferred Ugandan Ironwood because of its stiffness and flexibility compared to other woods.  Also it had the smallest distance between leaves on the branches and even the leaf surface area was the smallest.

The researchers believe  that the chimps turn to Ugandan Ironwood as it offers good protection against predators and pathogens and also aids in temperature regulation and gives high levels of comfort.

Dr. Samson added, "Chimpanzees, like humans, are highly selective when it comes to where they sleep. This suggests that for apes there is something inherently attractive about a comfortable bed--down to what kind of wood you use to make it."

The study was documented in the journal PLOS One.