Archive for February 2010
Liverpool, England - New research from scientists in Liverpool has revealed the relationship between agility and vision in mammals. The study, published today in the Journal of Anatomy, sampled 51 species to compare the relationship between agility and vision between frontal eyed species, such as cats, to lateral-eyed mammals such as rabbits, to establish if the positioning of the eyes resulted in limitations to speed and agility.
“Footballers do it, cheetahs do it, and even sedentary academics can do it. We all have the ability to visually track an object whilst on the move and you don't give a second thought to the effort involved,” explained co-author Dr Nathan Jeffery from the University of Liverpool. “As you walk or run your head swings up and down, tilts from side to side and rotates. Three semicircular canals of fluid found on each side of the skull sense these movements, one for each direction. These then send signals via the brain to three pairs of muscles that move the eyeball in the opposite direction and ensure that you can keep your eye on the ball, gazelle or the beer in your hand.”
This process, known as the vestibulo-ocular reflex, is affected by the directions sensed by the canals and the pull directions of the eye muscles. In mammals, the eyes can be on the side of the head, as with rabbits, or at the front of the head like in cats, however the position of the canals is basically the same. In some mammals the brain must do extra calculations to adjust the signal from the canals to match the different pull directions of the eye muscles.
“In our study we wanted to find out if these extra calculations placed any limitations on how fast an animal could move,” said co-author Phillip Cox. “We asked if there could be a point whereby, if an animal moves too quickly it could result in the brain being unable to adjust the signals from canal to muscle planes, which in turn would result in blurred vision.” The work was funded by the Biotechnology and Biological Sciences Research Council.
The team used MRI scanners to analyse the arrangement of canals and eye muscles in 51 species of mammal including giraffes, camels and zebra, tree shrews, bats and sloths. Astonishingly, the team found that the position of canals and eye muscles had no effect on the ability to see clearly at speed. In theory, a Sloth could travel as fast as a Cheetah without blurring its vision.
The team also found evidence suggesting that the role of the extraocular muscles switches with changes of eye position. For instance, muscles that make up-down compensatory movements in frontal-eyed species appear aligned for torsional movements in lateral-eyed species. Before this, scientists had assumed that major rewiring of the connections was essential to adapt the reflex to changes of eye position.
“Switching between muscles offers an economical way of adapting the vestibulo-ocular reflex to changes of eye position without major rewiring of the connections or changes of canal orientations,” concluded Dr Jeffery. “The mammalian brain can apparently cope with the extra demands placed on it whether the eyes are at the front, side or almost at the back of the head.”
Puppy farming, bad breeding practices and canine welfare in general have been recent topics of discussion and with Crufts just around the corner the media spotlight will be falling in this direction once again.
Julie Sharrocks, owner of website MyPetYourPet which is dedicated to keeping animal owners and breeders in touch, is seizing the moment to appeal to dog lovers everywhere to come together to do their part for canine welfare in a grass-roots campaign.
Over the course of the next few months MyPetYourPet.net is asking UK dog owners to register their pets, both living and deceased, with the site so that a comprehensive picture of the health, nature and behavioural characteristics of our nation’s dogs can constructed.
The websites founder Julie Sharrocks explains:
“Whilst the Government, the Kennel Club and canine charities all have major roles to play in achieving healthy dogs so do the public in general. If, as conscientious dog owners, we come together then we can amass an unprecedented wealth of information which will un-mask bad breeders and prevent purchasers from buying puppies and dogs that are not right for their family circumstances, dogs that will eventually end up on the streets, or in rescue homes or put down. We are a nation of dog lovers so why leave it to the authorities to stamp out bad breeding and mistreatment when we can have a massive impact on canine welfare ourselves”.
MyPetYourPet.net is quick, simple and entirely free to use. When an owner registers their pets a unique search facility slots them into a canine family tree. All dogs registered with the site are automatically linked to all of their registered relatives – their parents, offspring, siblings, half-siblings and more distant relatives backwards and forwards ad infinitum along a bloodline.
As part of the registration process owners are asked to provide, amongst other information, details about the nature and temperament of their pet and about any major illnesses or health problems their pet has or has had in the past. A wealth of medical and behavioural data will be available to all interested parties and this level of transparency will, by its very nature, weed out unscrupulous breeders. Potential purchasers will be able to use the anecdotal, family experience based information to choose dogs and puppies which are right for them and will very easily be able to see which breeders produce litters with problems and which do not, the move towards breeders with impeccable track records will be consumer lead.
A lady in Harrisburg has a special visitor who comes to see her cat each morning!! She finally got around to taking some pictures!
A new study has found that the UK domestic cat and dog population is larger than previously reported by industry figures. Cats and dogs are one of the most popular pets in the UK but it has been over 20 years since domestic cat and dog population estimates in the UK have been published in scientific peer-reviewed journals.
The paper published in the Veterinary Record by Dr Jane Murray in the Department of Clinical Veterinary Science at BristolUniversity and colleagues, aimed to estimate the number of UK domestic cats and dogs and identify the characteristics of their owners. The figures are also useful to the animal health and welfare professions, including rescue charities, which can use these and future estimates to assess population changes.
In 2007, a telephone survey of households randomly selected from the electoral roll revealed that cats and dogs were owned by 26 per cent and 31 per cent of households, respectively. The number of owned cats and dogs were predicted by two variables: the number of people in the household and the geographical location (London/rest of UK) of the household. UK census information and mid-year population estimates of the number of households and the average household size in 2006 in England, Wales, Scotland and Northern Ireland were used to estimate that UK households owned approximately 10.3 million cats and 10.5 million dogs in 2006.
Characteristics associated with cat and dog ownership were also identified. Cats were more likely to be owned by; households with gardens, semi-urban/rural households, households with someone qualified to degree level, respondents who were female and respondents who were aged less than 65 years. Cats were less likely to be owned by households with one or more dogs.
The likelihood of dog ownership increased as the household size increased. Dogs were more likely to be owned by households with gardens, rural households and less likely to be owned by households with someone educated to degree level and households with cats or children aged less than 11 years.
Female respondents and those aged less than 55 years were more likely to report dog ownership than other respondents. Dogs were less likely to be owned by households with one or more cats.
Dr Jane Murray, Cats Protection Lecturer in Feline Epidemiology, commenting on the research, said: “The study has shown many common factors relating to cat and dog ownership, such as a garden and rural location, but it has also identified some notable differences.
“In particular, the difference in the level of education achieved by a household owning cats and dogs. The reason for this association is unclear. It is unlikely to be related to household income as this variable was not shown to be significant but it could be related to household members with longer working hours having less time available to care for a dog.
“Past reports have suggested that the number of pet cats exceeds the number of pet dogs in the UK. However, results from our study suggest that there are similar numbers of pet cats and dogs.”
The researchers recommend the study is repeated in 2011, (the year of the next scheduled UK census), as any increase or decrease in population numbers will enable pet ownership trends to be monitored.