Sheep ain't no Dumb Blonds
It is time for a rethink because, despite all the jokes, new research studies have shown that sheep are smart, not dumb as many people claim.
Sheep are Very smart Indeed!
A particularly smart flock of sheep has been seen rolling, army-style, over cattle grids to get to other greener paddocks in an English village.
Cattle don't do that!
The latest study, published in New Scientist, by two researchers at the University of Cambridge found that sheep did better than most other animals on a psychological test that tricked most monkeys.
The researchers found that sheep could recognise patterns in colours, and quickly change their behaviour when the pattern changed. The sheep could even respond to the colour of shapes used as signs and placed next to their food bins, instead of the colour of the food bin itself.
The researchers put 7 adult female sheep through a set of increasingly tricky challenges. In one test the sheep were let into a pen that included a blue and a yellow bucket. The blue one contained food. After a few trials the sheep would always go directly to the blue bucket. When the food was instead placed into the yellow bucket, the sheep quickly learnt to focus on the yellow bin. They also mastered a more difficult game in which the food was still in one of the buckets but the clue to the location of the food was the colour of a cone placed nearby, not the colour of the bucket itself.
The researchers also tried a higher intellectual challenge, applying what is referred to a intra-dimensional and extra-dimensional set-shifting. This tested the sheep's ability to shift their attention, something that requires a sophisticated level of mental control. In intra-dimensional set-shifting, the sheep had to choose a bucket based on an changed the set of colours. Instead of yellow and blue, the choice was green and purple. Humans find this easy to do, and the sheep could do it as well.
Extra-dimensional shifting is much harder, as the sheep were required to ignore the colour of the objects and instead based their decisions on the shape of the objects. Humans and other primates can do set-shifting, but many other animals struggle with it, although rats and mice can do it. This complex task is know to rely on the prefrontal cortex, a part of the brain that is much larger in humans than in other animals.
The sheep passed the tests with flying colours (excuse the pun), learning to adapt either to different pairs of colours or to the shape of the object rather than its colour.
These results show that it is now time to stop making fun of sheep that are often misunderstood because of their herding instinct, which is after all a smart way of dealing with predators.
Previous studies have shown other capabilities of 'smart sheep' that:
- They can recognise each other's faces, especially sheep they are socially close to – and they can remember the details of the fellow sheep in the flock for at least two years.
- They can also discriminate breeds, preferring to look at their own kind.
- They can group plants by family and memorise the correct route through a maze.
- They have sophisticated social lives too: rams become long-term buddies and stick up for each other in fights.
- Tests of sheep's ability with mazes, done over three days, and repeated after six weeks, assessed how quickly the sheep made it through the maze and how much time they spent at dead ends. On day one the sheep made it to the end of the maze in an average of 90 seconds, but by day three they had cut the time down by two-thirds and were taking fewer wrong turns. After six weeks they were still navigating their way through the maze in 30 seconds. To show this was the result of cognition as opposed to instinct some of the sheep were drugged with the memory-impairing drug scopolamine hydrobromide. The drugged sheep could not match the performance of their drug-free flockmates.
- Why are some people, especially sheep shearers, able to handle sheep so easily? It is a combination of an understanding of sheep behaviour and a lot of experience. The Australian method of controlling sheep that are being sheared is based on knowing that sheep will stop struggling if they cannot push against something. The shearer, by careful handling of the sheep and precise placement of knees, feet, and various other body parts, moves the sheep through a series of positions, none of which allows the sheep to push against anything. This, coupled with the shearer's experience, skill and confidence, allows them to remove wool with deceptive ease.
- Sheep also have a well-developed sense of individuality and can recognise the faces of at least 50 other sheep and 10 people and retain this information for at least two years. Scientists at the Babraham Institute in Cambridge also found that sheep react to facial expressions and, like humans, prefer a smile rather than a grimace.
Other Remarkable Animal Feats
- Fish are renowned for having a three-second memory; however, evidence suggests they can be highly manipulative and cultured.
- Parrots, when shown two different objects, can use language to describe differences in their colour, shape and texture.
- Chickens feel intention and expectation and can tell people apart.
- Gordon Gallup devised renowned test for self-awareness in animals by testing whether an animal can identify its own reflection in a mirror as an image of itself. This is done by marking the animal with two odourless dye spots. One spot is put on a part of the animal that would be visible in a mirror. The other spot is in an accessible but hidden part of the animal's body. Scientists observe then see whether the animal reacts by showing it is aware that the test dye spot is located on its own body while ignoring the control dye. The animal may turning towards the spot, may poke at the marking on the body (not the reflection) or attempt to remove it. Animals that have passed the mirror test include: rhesus macaques, all of the great apes (bonobos, chimpanzees, orangutans, humans, and gorillas), bottlenose dolphins, whales, elephants, European Magpies and domesticated Pigeons. Dogs, cats, and young human babies all fail the mirror test ( Most human children, less than about 18 months old, fail the mirror test.
- During World War I, German psychologist Wolfgang Köhler, showed that chimpanzees, when challenged with fruit hanging from a high ceiling, devised an intelligent way to get the fruit. They stacked boxes up to stand on to reach the fruit. They also made long sticks to reach food outside their enclosure. Researchers now know that apes and may other animals have a very sophisticated understanding of how to build and use tools to solve problems.
- Pigeons can tell the difference between female and male faces in paintings by different artists; they can also select pictures that belong to various categories such as trees.
- Green herons have been seen throwing an object in the water to lure curious fish - a trick that appears to have been reinvented by groups of birds living in different localities.
- In another study, investigators took four mature individual crows, and presented them with a tasty worm bobbing on surface of a glass of water, that was just out of reach of their peck. Then they put a heap of small stones besides the glass. After they considered the depth of the water's surface from the top of the glass, the crows picked up a number of pebbles and dropped them into the glass until the water level increased sufficiently for them to grab the worm. The crows didn’t try to catch the worm until they’d dropped in a certain number of pebbles into the glass, which suggested that the crows had estimated how many pebbles was needed.
- In the wild, New Caledonian crows make and use tools to fish for food. To further understand how the birds use tools, a University of Auckland team set seven wild crows a complicated problem involving three tools. The birds were placed in a cage with some out-of reach food. Also in the cage was a long stick, which could be used to get the food. However the stick was also out of reach, being place inside a box lined with bars, so the crows could see the stick. Also in the box was a short tool, which could be used to get the long stick, but which was attached to the end of a dangling piece of string tied to the crow's perch. The crows needed to work out that they needed to pull up the string to get the short tool and use it to get the long tool, to get the food. All the crows accomplished the task.
Relative Intelligence amongst Animal Groups
From various studies, scientists have constructed hierarchies of animal intelligence. Primates, whales, dolphins and porpoises are considered the smartest mammals. Among primates, humans and apes are smarter than monkeys, which are smarter than the more primitive types such as the shrews. Of the apes, bonobos and chimpanzees rank above orangutans, gibbons and gorillas. Dolphins and sperm whales are supposedly smarter than non-predatory baleen whales such as blue whales (though test are difficult!). Among birds, scientists consider parrots, owls, crows and ravens the brightest.
Such a hierarchy argues is contrary to the idea that intelligence evolved along a single path, culminating in humans. Instead intellect seems to have emerged independently in birds as well as mammals and also in cetaceans and primates.
Size of Brain
Intelligence does not seem to be related to brain size. For example, clever small animals such as rats, parrots, ravens, and the smaller apes have small brains, whereas some large animals such as horses and cows with large brains are relatively less intelligent. The size of the brain cannot explain human intelligence either. Sperm and killer whales have brains weighing 8-9kg kilograms, elephants have 5 kg brains, all of which are much larger the 1.4 kg of human brains.
The relative brain size - the ratio of brain to body weight - does not provide an explanation either. Humans brains are relatively large at about 2 % of our body weight, whereas the blue whale's brain is less than one 100th of a percent of its weight. Some tiny mammals have relatively large brain sizes but are not very smart. In general, small animals have relatively large brains, and large animals have smaller ones.
© 2011 Dr. John Anderson