Culture and tradition are two seemingly unlikely words to use when talking about rat behaviour but that is exactly what we are going to do in this blog post.

Many people dislike rats, regarding them as vermin and, as such, we wage war on them every day.This persecution has provided a surprising opportunity for another fascinating insight into the lives of sentient animals.

Animals in a group may learn from each other and pass this information on from one generation to the next –  scientists call this ‘cultural transmission’.  However, the behaviour they learn may not necessarily be picked up by a different group of the same species. There are many examples of rats doing just that!

We try to exterminate rats using poisons such as warfarin which makes them bleed to death. But, you can’t fool a rat! In some parts of England rats became impossible to exterminate even with new sophisticated poisons because they learn what is safe to eat by picking up cues from other rats and the environment.

Rats use each other as taste testers, eating food that familiar rats have eaten and avoiding foods that made them sick.  They must know another rat very well and spend time with them to learn that food should be avoided. If a stranger rat is severely ill, a rat will still eat the food because they don’t know them and so can’t pick up on their subtle cues.

In one experiment on a group of wild rats, scientists first observed the rats regularly eating two types of food (X and Y). They then poisoned food X with a solution that made the rats temporarily ill but did not kill them.  The entire colony gave up eating food X even when it was no longer poisoned and this behaviour continued for many generations, long after the rats who were originally poisoned were gone. It is this ability to learn from each other and pass this knowledge on to young rats which keeps them alive and thriving in the face of our numerous attempts at ‘pest’ control.

In another example of cultural transmission in rats, Joseph Terkel found a unique group of rats in Israel who only ate pine cone seeds and he wanted to see if this behaviour was culturally transmitted. The rats were very skilled at stripping the pine cones of their seeds with a  “no fuss, no waste” technique.

When he bred some of these rats, he found that those who had never been shown the special technique of opening pine cones were unable to survive on them because they used too much energy opening them up.  He knew that this behaviour wasn’t genetic because rat pups born to mothers who could strip pine cones effectively were swopped with the pups of mothers who couldn’t.  He found that only the pups that were raised by a mother who knew the pine cone stripping technique learned how to do it.   So the pine cone eating technique was culturally passed from one generation to the next, just as in human society.

Sources:

1. Terkel, Joseph. Cultural Transmission of Feeding Behavior in the Black Rat (Rattus rattus). Social Learning in Animals: The Roots of Culture. Ed. Cecelia M. Heyes and Bennett G. Galef. San Diego: Academic P, 1996. 17-48.
2. Dawkins, M.S. (1998) Through Our Eyes Only. Oxford University Press. Pp 43-52.

Note:

Compassion in World Farming is opposed to any animal experimentation that causes pain or suffering to animals. However, where such experiments increase our understanding of animal sentience, we will report them in the long term interest of all animals.

The first chapter, “Release”, is linked below and visit www.ratlife.org to see the other chapters – well worth watching!

Berdoy, M. 2002. The Laboratory Rat: A Natural History. Film. 27 minutes. www.ratlife.org

This film clip shows the rats who were being tickled.

Professor Marc Bekoff tells us that young rats also love to play. They enjoy chasing, wrestling, boxing and jumping on each other. When they play, rats follow rules to show they are playing. They use their snout to gently rub their playmate’s neck. The playmate then wriggles away or runs off, as you would to stop somebody tickling you.

In a fight, rather than a gentle touch to the neck, rats use a different signal: they bite their opponent’s rump! 

This ability to understand another animal’s communication, and how to respond to it, is a strong indicator of animal sentience.

A number of rats were trained to tell the difference between a short and a long burst of noise.  They then had to tell the researchers whether it was a long or short noise by pressing a lever. 

If they got the answer right, they would get a larger reward of treats.  If their answer was wrong, they did not get any reward.  If they chose not to answer, they got a small number of treats.

They were usually able to choose correctly. When it was too difficult to classify the noise as “short” or “long”, because it was in between the two, the rats chose not to answer, showing that they understood they might give the wrong answer.

Previously, scientists thought that only humans and other members of the primate family were capable of this type of understanding.  This shows us again that many other animals have unsuspected depths and abilities.