Self-freezing frogs--it's true - News - The Prism

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Photo credit: Jens Gade, iStock\ThinkstocK

WASHINGTON (VR)— I know what you're thinking, a frogcicle will never become the top flavor at Baskin Robins, but for the Alaskan wood frog the genetic trick has become a very important survival trait. What the frog does, according to Don Larson, a Ph.D. student at Fairbanks, is dig a shallow hole near ponds where it breeds. After the hole fills with water, it will wade in and wait until the water freezes. This trick allows the wood frog to freeze up to 60% of its body, so as to reduce calorie consumption, and allow it to survive until the Spring thaw.

"So, when we say about 60-70% of their body water's frozen, the other percent is the water really inside their cells. So, it's everything around their cells that's freezing." Larson says that wood frogs not only practice their own form of cryogenics, but practice a form of camouflage to avoid predators while they are frozen. "They make sure to hibernate under leaves so they're pretty well covered, and I can tell you from my own experience that these guys are very, very hard to find." Mind you, it's not just a petal or two hiding them. They are hiding under leaves and buried under snow. Larson once spent two weeks raking, hunting for frogs, only to find two of them. That's a pretty bad payoff for 196 hours of work. It's even worse, when Larson estimates there were at least ten times that number available to be found. Larson found that the frogs were able to lower their body temperature as far as -20 degrees Celsius without harm to their bodies or their cell structure. "We have some evidence that they might be able to go even lower than that, but the thing that tells us is they're very hardy, and able to survive these conditions very well is we didn't see any wood frogs die." The wood frog is not completely unique in its ability to freeze, thaw, and walk away. There are some insects who've shown this quality as well as the Siberian salamander. The key to the survival of the wood frog may have to do with glucose... more at the audio link. Source: Voice of Russia - US Edition

Read More........→June 09, 2016

Aggression in dogs: New study aims to 'bust some myths'

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Academics at the University of Bristol’s School of Veterinary Sciences have been investigating dog aggression towards people with a survey of UK dog owners which has been published online in Applied Animal Behaviour Science. Dr Rachel Casey is Senior Lecturer in Companion Animal Behaviour and led the research. VOR's Tim Ecott asked her what had prompted the survey.

"Aggression is a big public health issue," Dr Casey says. "People have even been killed by dogs, so it's a serious problem for people, but it's also a welfare issue for dogs, because it they're showing aggression, it's likely to be because they're feeling stressed in their environment. "We wanted to look not at serious aggression such as biting, but at any sign of aggression, such as barking or lunging." What did you find? "We asked about aggression in different situations. Are dogs generally aggressive or in very specific situations? We asked owners about the dog's behaviour in the family, out for walks, and when people visit the household. The results varied quite a lot between the contexts." "It tells us about the behaviour, not why the dogs are doing it. It's a baseline." There's a danger that these findings will be taken up by people who think that dogs should be more controlled, or vice versa, that it's only a small number of dogs that are aggressive. "Like any stats, you can argue them in any direction. But we're interested in information. At the moment, people denigrate all dogs, or certain breeds, and we wanted to find out much more detailed information to bust some of the myths." "We looked at breeds, but also owner age, training, gender, gender status and so on." Do you think that people like the idea of having a dog but don't really know how to train or bond with it in an increasingly urban society? "It's really important to get across to everybody before they get a dog to really think about it. Not just the financial and health requirements, but also the behavioural requirements -dogs have quite a lot of needs; every dog will need exercise, mental stimulation, lots to do during the day. So everybody who's thinking of getting a dog needs to address very carefully whether a dog is suitable for their household and lifestyle." (Voice of Russia) The survey, background The study, led by academics at the University of Bristol’s School of Veterinary Sciences and published online inApplied Animal Behaviour Science, investigated the occurrence of dog aggression towards people with a survey of UK dog owners. Nearly 15,000 questionnaires were distributed to dog owners of which 4,000 were returned and used in the analysis. The researchers found that aggression towards unfamiliar people was reported more commonly by owners than aggression to family members. Nearly seven percent of owners responded that their dog barked, lunged, growled or actually bit when people came to the house, and five percent reported these behaviours on meeting people when out on walks. In contrast, about three percent of dogs were suggested by owners to show aggressive behaviour towards family members. The study highlighted that the majority of dogs showing aggression do so in just one of these situations. This indicates that the common tendency to categorise dogs as either generally ‘safe’ or ‘vicious’ is a misconception, and that most dogs show aggression as a learnt response to particular situations. The study also compared the characteristics of those dogs reported to show aggression with those which had never done so. It was revealed that factors such as training classes attended, type of training method used, the sex and neuter status of dogs, the age category of owners, and the breed of dogs were all associated with the occurrence of aggression. Interestingly, different risk factors were found to be significant in statistical models examining aggression to family members and unfamiliar people. This suggests that different factors are important in the development of aggressive signs depending on the situation. The research also highlighted that although general characteristics, such as breed type, are significant risk factors across large populations they explain only a small amount of the overall difference between aggressive and non-aggressive dogs. This suggests that it is not appropriate to evaluate the risk of aggressive behaviour in an individual dog using characteristics such as breed type. (University of Bristol) Source: Article

Read More........→January 08, 2015