It was an accepted theory that creatures that have bigger brains have smaller intestines in order to divert energy to the brain. This is also evidenced in apes that have smaller brains and hence, larger intestines than humans. Latest research, however, has disapproved this theory and established that creatures with bigger brains do not necessarily have smaller intestines. The research has also proved that the intestines of creatures with bigger brains are bigger. The research was carried out researchers in Zurich.

The lead researcher of the study is Ana Navarrete. She has spent a lot of time studying the remains of animals in museums and zoos. The author said that the data considered for the study consists of a hundred species, which range from “shrews to stags”. Ana Navarrete is a student of PhD. Karin Isler, the senior author of the study said that correct results can only be obtained when adipose tissues are studied. Adipose tissues makes up nearly 50% of the body mass. The research also showed that there is no correlation between the size of the brain and body mass. The size of the creature’s brain does not have a negative influence on the size of other tissues.

However, there are strong proofs to show that the amount of fat in the body affects the size of the brain. The influence of fat on the brain has evolutionary roots as well. During the course of study, researchers also found that the fat storage capacity of the creature influences the size of the brain in indirect proportion. This means that more the capacity of the creature to store fat in the body, lesser will be the size of the brain. Animals that have more fat deposits in the body require more energy to perform ever simple functions such as walking and running. This makes the energy supplied to the brain lower and hence, the brain shrinks. The known exceptions to this law are seals, whales and humans.

The researchers from Zurich said that the increase in the size of the brain and subsequent increase in the consumption of energy by the organ was set into motion nearly 2 million years ago. Various evolutionary factors such as communal culture, lifestyle and food habits have an influence on the development of brain and gut. Humans evolved differently and because they walk straight, the energy consumption for such activities is lower than in apes. This saves energy that is diverted to the brain. So humans can have both large intestines and large brains.