More than two years ago, 20 tenrecs arrived at the Princeton University research lab. Tenrecs live only in Madagascar, from where they were taken out by Dr. Edwin Gould. There are several types of these animals. The tenrecs studied at Princeton live in large groups in the Madagascar forests, feeding on worms and insects, which they search for at night, rummaging through the leaves with their long muzzles.
Researchers were interested in the ability of tenrecs to “squeak” - to make high-frequency sounds with the help of needles located on their backs. Some scientists believe that these sounds help the animals themselves to stay together in the dark, while at the same time not providing an opportunity for enemies who are not endowed with fine hearing to determine the location of tenrecs.
Others suggest that tenrecs use high-frequency sounds as sonar to avoid obstacles - these sounds are reflected from them.
What do tenrecs look like?
The tenrec is slightly smaller than a rat. He is black and white, his body is covered with hair, sometimes with bristles, sometimes with needles. If you tease him, he will quickly and unexpectedly raise his needles. Then it is difficult to hold it in your hands.
On the back of the tenrec, under long hair and needles, there are about a dozen shorter, like stumps, needles, the contact of which with each other creates sounds with an oscillation frequency of 25 to 40 thousand hertz. And since the human ear perceives sounds no more than 15-20 thousand hertz, we cannot hear the “creaking” of tenrecs.
By measuring the frequency of oscillations, the scientists decided to establish whether the animals themselves hear the sounds that they produce. For this, a technique developed at Princeton and tested on various animals was used. By placing electrodes at the point in the inner ear where sound vibrations are converted into electrical signals, the researchers were able to "catch" the sound going to the animal's brain. It was found that tenrecs can indeed perceive high-frequency vibrations. But whether they have any "code" or "language" to communicate with each other has remained unexplained for many reasons. Experimenters pursued failures.
First, as a result of a heating malfunction, three tropical animals died from the cold. After this, a new misfortune broke out: an uncontrollable fight broke out. Apparently, one of the dead was the leader of the group, and the establishment of a new hierarchy followed. When peace was restored, only five critters remained. Since the researchers had no experience with tenrecs, and besides, their anatomy is not well known, experiments on the introduction of electrodes cost the lives of four more animals. And then the study of the auditory sensations of a single tenrec went on.
Princeton scientists have no fond memories of working with these animals. Tenrecs are very excitable. Abundant wool and sharp needles made all manipulations with them very difficult. And to all this - an extremely unpleasant smell that they emit. Their food gave them a lot of trouble. It turned out that the only food they agree to in captivity is live earthworms. Local resources were soon depleted. The arrival of air transport with food for the tenrecs was expected, and only a natural disaster and a “civil” war between the tenrecs, which ended so badly for them, saved the scientists from large expenses, and the local population of worms from complete destruction.
Tenrecs have absolutely no ability to help experimenters in their work. Usually, to test whether an animal hears a sound, it develops certain reactions to this sound. Tenrecs, as it was quickly discovered, completely ignore experimental situations.
They tried to train them to avoid a weak electric shock. Pigeons, cats, mice and many other animals can easily cope with this task. But the tenrecs showed absolutely no inclination to learn.
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