BBC Wildlife , November 1999, Vol. 17, page 42-51
Behaviour / Raccoons
Paws for thought
You’ve got to hand it to raccoons - They have evolved incredibly sensitive forepaws to help them map their world. And now they’ve made themselves at home in Europe, where they seem to have developed some interesting habits.
Photos: Ingo Bartussek, Monika Paulat, Story: Ulf Hohmann
Deep in the Solling, Lower Saxony, a raccoon scoots up a large tree. It's Jack, who we have tracked, through his radio collar, to a beech forest near our research centre. As we leave the car, he takes refuge in his tree, as he always does when something comes close that he's not totally sure of. We start talking softly, as we always do when we approach one of our forest friends. As soon as Jack recognises our voices, he comes down from the tree. This takes some time, as he keeps stopping to listen out for danger in the surrounding darkness. He knows that the sound of his claws scratching could easily attract a predator's attention.
So we chat, and when Jack reaches the ground, we squat down gently beside him. A few seconds later, he crawls onto Franziska's lap, licking her hands and face quite casually. This is a raccoon's way of saying hello to someone he knows well. And there is no one Jack knows better than Franziska. A few moments later, he jumps down and disappears into the night without so much as a backward glance. It doesn't take us long to find the two reflecting light spots of his eyes in our torch-beams. He has found the trunk of another large beech, less than 20 metres away. This one has several small holes between its roots. Jacks sniffs into every hole very carefully and then reaches into one of them. We watch as his entire arm disappears. Then he turns his head away, unseeing eyes pointing into nowhere, as he focuses all his concentration onto his feeling hand. After a few moments, he draws his arm back, holding a large wriggling wood mouse in his paw. The second paw helps to keep a hold on the prey. Then he kills his victim with a short bite into its head and eats it with pronounced satisfaction. This procedure is repeated 10 times within the next 45 minutes. He fails on just three occasions.
The raccoon's ultra-sensitive forepaw is, undoubtedly, its secret weapon. Within the somatic sensory cortex of the raccoon's brain, a huge area of nerve cells is dedicated to computing and evaluating the information gathered by millions of receptors on the underside of each of its fingers. These bits of data are combined in higher areas of the brain, resulting in what is called an impression - in this case, a feeling impression. Over thousands of years of evolution, selection has forced the raccoon's brain to reserve larger and larger areas for dealing with tactile information from the forepaws - it now takes up 64 per cent of the whole somatic sensory cortex. There is good reason to assume that a feeling raccoon constructs a 'picture' of its immediate surroundings that is as complex and detailed as the one we see with our eyes. This may help explain why a feeling raccoon, turning its head away, appears absent - it is a hand-fixed animal; we are eye-fixed. I believe that a captive raccoon in a zoo being watched by visitors regards them as 'absent', too - perhaps because they usually have their hands stuck uselessly in their pockets.
The raccoon is a much-misunderstood creature. Its tremendous tactile cortex is a unique development among carnivores, enabling incredibly efficient foraging, especially at night. But in captivity, it is no longer necessary for the raccoon to feel out its food. Yet its paws want to be active, even though its bowl is always full. In order not to go mad, the bored, near-crazy animal will start to touch and play with its food just to get some respite from its natural urges. And so it puts the food in its waterbowl and plays about with it. In its mind, it is once again catching crabs on the riverside, seeking out slippery trout in the currents, searching for earthworms along a muddy bank - how entertaining for the audience! It looks like a cute little bear washing its dirty food. The misapprehension that this image has created has led to its German name 'washbear', like its scientific species name lotor, the washer.
The rest of the story of the raccoon in Germany is full of further misunderstandings. This exceptional mammal was introduced into the forests to provide one more valuable fur-bearer to hunt. No one realised that this would open the door for one of the most successful carnivores of North and Central America to conquer Europe and western Asia. The population grew fast and colonised forest after forest, beginning west of Kassel, where the first releases took place in the 1930s. Today, the raccoon is found throughout Germany and has crossed into all neighbouring countries. Nobody knows how many we now have. The 1960s and 1970s were the hardest time for what had by then become a hated alien. The pelt market had collapsed, and, with no economic justification for its existence, the raccoon became seen as no more than a masked thief, robbing farmers of crops and animal feed. As a result, my father's generation set about trying to kill as many raccoons as possible. But it proved impossible to exterminate the German raccoon. The whole bloody campaign against these rascals revealed just one fact: that the raccoon had made itself at home in the oak-rich forests of its new motherland.
In the 1980s, the raccoon became accepted as native in many German states. In 1992, along with the Institute of Wildlife Biology at the University of Göttingen, I initiated the first study of its behaviour, to try to find out whether a European environment had changed any of its habits. Fortunately, the raccoon is one of the best-researched carnivores in the US, and so there were plenty of data for me to compare with our future findings. Most of what I read told me that the raccoon was solitary and that males were more or less territorial and polygynous (mating with more than one female). The female seeks contact with males only during her brief oestrous cycle in late winter; otherwise, she roams and lives with her young of the year.
As we expected, our first capture in our study area was an adult female, followed seven days later by an adult male - presumably the territory holder. But then we caught another adult male. This was not what we had expected. When we followed these radio-collared males, it became clear that they hadn't been reading the literature: they travelled together, foraged together and denned together. During the next few months, we caught four more adult males, all showing the same, non-textbook tendency to partner-up.
Finally, in September 1994, I plucked up my courage and wrote to Professor Erik Fritzell of the University of Missouri, Columbia, an expert in raccoons' social behaviour, explaining how the lifestyle of German raccoon males seemed to differ from that of their American relatives. Professor Fritzell replied, telling me that one of his students, Stanley Dean Gehrt, had started a similar study of raccoons in Texas and had observed the same behaviour.
Over the next few years, I focused my interest on the relationships between males. I took blood samples from every raccoon we caught and sent them to a lab in Heidelberg for genetic analysis. While neighbouring adult females always seemed to be close relatives - grandmothers, grandchildren, aunts or nieces - the DNA-fingerprints did not offer similar proof about neighbouring males. But clearly, these coalitions were more than mere bondings between brothers or fathers and sons. What was going on?
I planned an experiment. We would hand-rear raccoon cubs in a natural habitat, without any cages or enclosures, in an area where wild raccoons occur, so that we could follow them more closely. We had the perfect site for the study, around our research centre, an old hunting lodge in the centre of the Solling forest. But then we had to find the perfect mother: someone who was willing to work at night but with no guarantee of regular sleep during the daytime; someone who would be devoted to the cubs but with enough distance to be a cool observer. In 1995, I met the perfect candidate: forest student Franziska Kalz. In May, we bought five cubs from a breeder - three males and two females. Franziska spent night after night with her small family in the foggy woods around the lodge, collecting thousands of pieces of data on their growth rate, improving mobility and social development. Jack was the largest male and, from the very beginning, the one who related best to Franziska.
In August, when the young raccoons were almost five months old, Franziska noted an increasing independence in the cubs - crunch time was close: would our experiment work or not? Radio collars were fitted, and in November, Jack began to wander outside his mother's home range, visiting oak and beech stands 2km to the north-east of the lodge. Then he went missing. Two days later, we tracked him down. I held back as Franziska approached him, slowly and calmly, unsure of whether or not he would accept her presence in his new territory. But the moment he recognised her voice, he came to her. Our tension dissolved immediately - we were in with a chance of observing his interactions with other raccoons.
Our work with Jack taught us a great deal about a raccoon's life. We saw how an experienced raccoon catches earthworms or finds - in complete darkness - ripe raspberries among raw ones. We learned what makes a good latrine site and how raccoons find appropriate den trees. We found that a raccoon's diet is made up mostly of small items: insects, snails and a huge amount of indefinable things fished out of streams, thanks to the raccoon's incredible forepaws. Most of all, Jack showed us how much we still have to learn about the raccoon.
In January, shortly before the breeding season started, I found Jack denning in an old badger burrow alongside a male we didn't know. He came out of the den to greet me and seemed confused that his new friend showed so little interest in me. By this time, I had developed the hypothesis that forming a coalition with another male maximises reproductive success. It could well be a response to the tendency of female offspring to stay close to their birthplace, which leads to a clumped distribution of females. In these circumstances, a male won't lose much reproductive success by accepting and co-operating with other males. As companions, a pair can establish a larger territory. And it seems that multi-male groups are so overwhelmingly successful, that males who don't pair up end up having no access to females at all. But the reasons for pairing up remain obscure and may have more to do with denning or feeding than reproduction.
Sadly, in October 1996, a late-evening phone call brought an abrupt end to our research. Two dogs had found Jack sleeping in a blackberry bush and killed him. "He fought with great courage," the dogs' owner told us. Jack had been the only male of our brood to reach adulthood - the others were killed by cars or poison. In his short life, he showed us that raccoons are capable of maintaining long-lasting relationships with humans. He was probably about to embark on what could have been a lifelong relationship with another male raccoon. How that would have developed, we will never know, but thanks to Jack, we are now beginning to understand some of the mysteries of the wild raccoon's behaviour.
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