Crocodiles are not necessarily considered to be intellectual overflows. For hours they lie motionless along the bank of the river, in order to catch an incautious beast of prey. "Most people consider crocodiles to be lethargic, stupid and dull," says Vladimir Dinets of the University of Tennessee in Knoxville. The zoologist has gained a very different impression through his research
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Only recently, he found out that two crocodile species rely on a sophisticated hunting technique, using their sticks to attract their victims. Thus, the Panzerschsen belong to the rather exclusive circle of animals using tools - an ability which was considered typical humanly a few decades ago. And they are not the only reptiles with unimagined talents. Turtles and tigers have obviously been underestimated for a long time.
This is probably due to the fact that most behavioral researchers have traditionally concentrated on mammals or birds. There are countless studies on their use of tools. The spectrum ranges from chimps, which crack nuts with nuts, to crows poking with forks. All reptiles, birds and mammals, however, go back to a common ancestor who lived about 280 million years ago. There could be a common spiritual heritage.
Until recently, however, there was not a single reptile known to ease everyday life with any kind of aid. Until Vladimir Dinets and his colleagues came across the falling crocodiles. For the first time, the researcher observed the strange behavior of swamp crocodiles in India. For hours, the animals lay motionless in the shallow water of a pond and balanced small branches on their muzzle. Only when a heron landed and stretched the beak after such a branch, life came into the scenery: Suddenly the crocodile snapped and missed the heron just barely. An accident? Or had the reptile placed the branches deliberately on the snout to lure a prey? Nesting material is often scarce in heron colonies, so that a stick could be an effective bait for such birds.
Branches on the muzzle
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Only recently, he found out that two crocodile species rely on a sophisticated hunting technique, using their sticks to attract their victims. Thus, the Panzerschsen belong to the rather exclusive circle of animals using tools - an ability which was considered typical humanly a few decades ago. And they are not the only reptiles with unimagined talents. Turtles and tigers have obviously been underestimated for a long time.
This is probably due to the fact that most behavioral researchers have traditionally concentrated on mammals or birds. There are countless studies on their use of tools. The spectrum ranges from chimps, which crack nuts with nuts, to crows poking with forks. All reptiles, birds and mammals, however, go back to a common ancestor who lived about 280 million years ago. There could be a common spiritual heritage.
Until recently, however, there was not a single reptile known to ease everyday life with any kind of aid. Until Vladimir Dinets and his colleagues came across the falling crocodiles. For the first time, the researcher observed the strange behavior of swamp crocodiles in India. For hours, the animals lay motionless in the shallow water of a pond and balanced small branches on their muzzle. Only when a heron landed and stretched the beak after such a branch, life came into the scenery: Suddenly the crocodile snapped and missed the heron just barely. An accident? Or had the reptile placed the branches deliberately on the snout to lure a prey? Nesting material is often scarce in heron colonies, so that a stick could be an effective bait for such birds.
Branches on the muzzle
This was also reflected in the experiences of the employees of a crocodile farm in Florida. The Mississippi alligators there also showed a soft spot for branches - and they had success with the heron hunting. Dinets decided to systematically get to the bottom of the matter. For a year he has supervised alligators who lived in different waters of Louisiana - sometimes with and without herons colonies in the neighborhood.
The results were unambiguous: to carry sticks on the nose is apparently announced in alligator circles only to the brutzeit of the herons - especially in the nest building phase between March and April. And the neighbors of the bird colonies showed this behavior much more frequently than their colleagues in other sections of the same body of water. The animals therefore seem to use not only tools, but their use even to match the appropriate hunting season.
However, the researchers do not yet know whether it is an innate or learned behavior, a strategy developed individually by each animal, or a tradition passed down from generation to generation. "In any case, the results show how easily one can underestimate the intelligence even of well-known animals," says Dinets.
However, the researchers do not yet know whether it is an innate or learned behavior, a strategy developed individually by each animal, or a tradition passed down from generation to generation. "In any case, the results show how easily one can underestimate the intelligence even of well-known animals," says Dinets.
Other behavioral researchers have also made this experience. For example, a popular animal intelligence test is to show them photos. Do the candidates understand what is to be seen? Do they also recognize the difference between the image and the real object? Many birds and mammals have grown to this challenging mental challenge. But how would reptiles beat?
A team led by Anna Wilkinson from the University of Lincoln in the UK and Ludwig Huber from the University of Vienna tested this in South American killer turtles. The researchers initially gave the reptiles the choice between a molluscan and a non-edible object. If they decided to eat it, they were allowed to eat it. As soon as the animals understood this connection, the scientists replaced the real objects with color photographs. This, however, had little effect on the decision of the animals - they obviously recognized the photo on which a tasty piece of fruit could be seen and not.
The turtles came to their limits, however, when they were to decide between the picture and the real object. In these cases, they chose only the random principle. So you could not tell if it is a real or just a virtual treat acted.
In other tests, however, the animals have surprisingly performed well. So they willingly follow the eye of a fellow-fellow. If the light spot fixes on top of the wall, which they can not see themselves, they also look upwards in most cases. This does not sound particularly spectacular. Finally, it can be very useful to look where the companions are looking. Perhaps they have discovered an enemy or an interesting source of food. Many primates, but also goats and raven birds, are acting exactly according to this motto. Only in the wild they lead a much more sociable life than charcoal turtles. Why should these loners have a lot of interest in the direction of their peers? The researchers suspect that this behavior could be an heirloom of the common ancestor of reptiles, mammals and birds. It is possible that the loner turtles have kept it simple without much use.
Social loners
However, the turtles have also proved in other experiments that despite a tendency to self-bravery, one can orient themselves successfully to his fellow-species. For example, when it is necessary to walk around an obstacle to a feeding place. When they were on their own, all the animals tested failed on this task. If, on the other hand, they had observed a colleague who already knew the diversion, they were able to reach the goal without problems - some already at the first attempt. They could even transfer their knowledge to new situations where the obstacle had a different form. The team around Anna Wilkinson has thus demonstrated for the first time that social learning works even without a social and complex cohabitation.
At all, reptiles appear to be much more capable of learning than scientists had long trusted. They are therefore in a position to find a solution to new problems. This is shown by experiments conducted by Gordon Burghardt of the University of Tennessee at Knoxville and his colleagues with turtles and warriors. In it, Florida red-bellied turtles learned to knock over transparent plastic bottles in a very short time in order to get to the underlying food. And a year later, they could still remember this successful trick.
A similar task was also posed by the white-tailed warthogs, whom the researchers offered beutians in a transparent plastic tube. All eight candidates learned in ten minutes to open the flap at the end of the tube, to head in the head and eat the small mice. In the second experiment, it was even much faster. In a short time, the animals had learned to deal with the unknown apparatus properly - a performance with which they would not have to hide from mammals.