Why do ostriches, the largest living bird species, with the largest eggs of any bird, have two legs but four knees? Specifically, ostriches have four kneecaps, and therefore four knees. Emus and cassowaries have no kneecaps.
Sophie Regnault, and her research colleagues at the Royal Veterinary College in London, examined a dead ostrich donated to the college.
They bent and straightened the ostrich’s knees, and used an imaging technique called biplanar fluoroscopy to track how the bones moved. Then they built a simple model to understand how the kneecaps affected the leverage of the muscles controlling the knee.
Kneecaps help animals to flex the extensor muscles in their knees, so that they don’t need to exert force to straighten their knees.
However, ostriches have an upper kneecap and a lower kneecap on each leg that act differently from the kneecaps of other animals.
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The lark – a small diurnal songbird – rises early and is active during the day, whereas the owl – a large nocturnal bird – is active at night.
Psychology Today has documented a recent study on chronotypes – whether a person is a morning person (up with the lark) or a late night person (to bed with the owl) and who they attract as partners.
Many studies have been previously conducted on personality traits, but there has been limited studies on chronotypes. Chronotypical behaviour is a preference for rising early or going to bed late. Morning people are called larks (and they reach peak performance early in the day) and late night people are called owls (who perform well in the afternoon or evening).
However, there is a continuum, with most people clustering around the middle – a neutral chronotype.
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Scientists at the University of Liverpool in England have conducted a study on the benefits of pets for people with mental health problems.
Researcher Helen Brooks, and her colleagues at the University of Liverpool, studied 17 international research papers on pets and human benefits, particularly involving people with mental health problems. They studied the extent, nature, and quality of the evidence of pet ownership.
They found positive, negative, and neutral impacts of pets on people with mental health problems. However, there were many ways in which pets contributed to the work associated with managing a mental health condition, particularly in times of crisis, trauma, or stress.
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Scientists have learned that the size of groups of primates is not random. There is a preferred group size.
Excluding humans, primates are mammals that have two arms and two legs, with the ability to climb trees (with most having five digits on each limb and an opposable thumb). Primates have large brains, and forward-facing eyes. Primates include apes, monkeys, lemurs, tarsiers, and lorises.
Susanne Shultz at the University of Manchester in the United Kingdom, and her research colleagues, compared group sizes in 215 primate species.
The researchers found that the average number in a group varied between species but was always clustered around five distinct sizes.
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Dogs help improve the health and longevity of people’s lives – and some dogs help more than others, says a new study. New research shows that certain dog breeds are more beneficial for humans than other breeds.
Previous studies have shown that dogs, and dog ownership, can reduce people’s risk of heart disease. A study published in Scientific Reports confirms this and explores which dog breeds are more conducive to improved health for humans.
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A recent British study shows that sheep have a highly developed ability to recognize the faces of celebrities.
Although it has long been known that sheep are able to recognize the faces of their human owners and handlers, scientists have now shown that sheep can be trained to recognize images of famous people.
Professor Jenny Morton, the lead scientist in the Cambridge University study, said that the study showed that sheep have face-recognition abilities comparable with those of humans or monkeys.
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Dogs have a lot more nerve cells in their nasal (nose) cavities (their nostrils) than humans do. Dogs also have and a wider variety of receptors that attract odour molecules.
A research team led by Brent Craven of Pennsylvania State University in University Park in 2008 has shown that dogs can sort smells into categories before the information gets to their brains. The brain then identifies the smell.
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A taxonomist classifies and categorizes plants and animals. The profession is called taxonomy.
It can be a difficult job, because their task is to look at the similarities and differences in animals, and to determine which animals are related.
Sometimes, when the taxonomist recieves more information, he or she may change the category of an animal.
For example, the taxonomic classification of the Red Panda (Ailurus fulgens) has been very difficult. Is it related to the Giant Panda or is it related to the raccoon?
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Eggs can be big or small, round or pointy.
There are many explanations for the variety of birds’ egg shapes.
Mary Caswell Stoddard and her researchers of Princeton University analysed the shape almost 50,000 eggs from around 1,400 species of birds in museum collections. She thinks the shape of a female bird’s wing determines the shape of the eggs.
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Every year thousands of wildebeest drown or are eaten by crocodiles when they cross Kenya’s Mara river during their annual migration.
The mass annual journey of 1.2 million wildebeest (also known as gnus) from the Serengeti in Tanzania to the Mara in Kenya in Africa is the largest mammal migration in the world, and certainly the largest annual mass drowning of wildebeest.
Amanda Subalusky at Yale University has measured the nutrients released into the river ecosystem from the 1100 tonnes of biomass from about 6,200 wildebeest carcasses (dead bodies) that float downstream in the Mara river each year. That includes 100 tonnes of carbon, 25 tonnes of nitrogen and 13 tonnes of phosphorus.
Subalusky says that crocodiles and birds benefit from the carrion (decomposing bodies), particularly vultures. But the slow release of nutrients benefits everything in the river from fish to insects.
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There is a bird species of cormorant on the Galápagos Islands that cannot fly. It is the only cormorant species in the world that has lost its ability to fly. Why?
Emus and ostriches cannot fly. They are very large birds. The Galápagos Islands cormorant is not a very large bird.
Scientists have found the genes that are present in birds, mammals and most animals, that may have the answer. The genes are called C. elegans.
The genes affect bone growth. In birds, a mutation (change) of the genes cause a weaker breastbone and smaller wings, which are not effective for flying. Scientists think that the mutation of the genes in Galápagos Islands cormorants occurred about two million years ago.
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Almost all birds stand on one leg. Some can even sleep while standing on one leg. Why do they do it and why don’t they fall over?
Long-legged birds, such as storks and flamingos, often stand on one leg, but so do short-legged birds, such as ducks.
Birds generally don’t have feathers on their legs. Standing on one leg reduces heat loss. Birds tuck one leg under their feathered body to keep it warm, leaving only one leg exposed.
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