All posts by Artem Cheprasov

Dr. Artem Cheprasov was born in St. Petersburg, Russia. He then moved to the U.S. when he was a little boy. So no, he is not a spy. Or is he? He finished his studies in veterinary medicine at the top 10% of his class, conducted research, and discovered a cool mathematics algorithm; but we cannot confirm this as both Washington and Moscow have refused to comment on this matter either because he really is a spy or more likely because they have no idea who he even is.

Why does our cat present his back end he wants to be stroked?

Cat TailsUnless your cat is the famous Grumpy Cat, he or she probably enjoys being scratched and petted. Whenever you are actively scratching a friendly cat, your feline friend will naturally push the part of its body that is being touched closer to your hand for increased contact and stimulation. The neck is a favourite scratching area, but when it’s looking for a stroke, a cat will often present you with a less pleasant part – its back end. But don’t worry, she doesn’t want her bottom stroking…

There are a few theories as to why the back end is raised when being scratched, or when asking to be scratched. Most think it is to do with how kittens are raised and stimulated during cleaning. As cute as they may be, baby cats can’t clean themselves after they go to the toilet. And because poor hygiene can result in serious health problems, mum steps in to help out. Unlike human babies, kittens don’t (usually) wear diapers – so mother cat goes about things in a more direct way (we won’t spell it out for you, but if you remember that a cat’s tongue is about its only cleaning tool, you get the idea). This ritual means that from an early age, cats have a link between cuddles and attention from their mother (or from you)… and presenting their back end for a quick clean.

The back end is also involved in all sorts of kitty communication. For example, cats will often give each other a quick sniff when they meet for the first time, and some say the rear presentation is linked to sexual behaviour.

While we may never know its origins for sure, the likely explanation is that such a posture of aiming the hind end toward the owner is one of actively showing and asking for positivity, acceptance, and benevolence in kitty language.

What’s more, over time, the cat may learn that if they extend a certain part of their body towards you, they will get what they want – a nice backrub. See how your cat has trained you? They’re sneaky like that.

Answer by Artem Cheprasov (with Nick Waszkowycz)

Image credit: hexion on flickr

Article by Artem Cheprasov

July 1, 2014

Dr. Artem Cheprasov was born in St. Petersburg, Russia. He then moved to the U.S. when he was a little boy. So no, he is not a spy. Or is he? He finished his studies in veterinary medicine at the top 10% of his class, conducted research, and discovered a cool mathematics algorithm; but we cannot confirm this as both Washington and Moscow have refused to comment on this matter either because he really is a spy or more likely because they have no idea who he even is.


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Can A Cat Carry A Litter Of Kittens With Different Fathers?

Kittens on a ChairCat biology is a little different to human biology. There are obvious differences – general cuteness of features, presence of retractable claws – as well as some less obvious differences. One of the differences you probably won’t have noticed (unless you are very intimate with your pet) is the way female cats ovulate and mate:

Queens (female cats) are called ‘induced ovulators’. This term is just a fancy way to say that queens do not release eggs from their ovaries – they do not ‘ovulate’ – until they mate with a tom (male cat). So, unlike humans, cats do not have periods every month.

But, it takes two to tango…

The tomcat’s penis has sharp spines, (yes spines) that dig into the queen’s vagina during mating. (Ouch… we don’t know if this is something the queen gets pleasure from!) We think these spines help trigger the release of hormones that lead to ovulation… and ultimately fertilisation.

But one session may not be enough: about half of all queens who mate with just one tom do not ovulate – and therefore do not have kittens. Therefore, to make sure she has a good chance of getting pregnant, she will need to have sex multiple times to have hormone levels that are high enough to trigger the release of her eggs. And as you can imagine, this mating may occur with more than one tomcat in the wild.

During the process of mating, sperm is deposited into the female reproductive tract. Cat sperm is hardy and can stay alive long enough in there to await the release of the eggs. So, when the eggs are finally released, the sperm from all the different tomcats fight their way to the eggs in order to fertilize them.

This process of multiple fathers fertilizing different eggs released during the same period of ovulation is technically called “heteropaternal superfecundation”. Catchy.

And if you thought it only happens in cats, you’d be way off. It can happen in many animals, humans included – just see here and here.

I smell paternity suits…

Answer by Artem Cheprasov

Image credit: Robert Couse-Baker on flickr

Article by Artem Cheprasov

June 10, 2014

Dr. Artem Cheprasov was born in St. Petersburg, Russia. He then moved to the U.S. when he was a little boy. So no, he is not a spy. Or is he? He finished his studies in veterinary medicine at the top 10% of his class, conducted research, and discovered a cool mathematics algorithm; but we cannot confirm this as both Washington and Moscow have refused to comment on this matter either because he really is a spy or more likely because they have no idea who he even is.


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How can hand sanitizers kill viruses? Yet we can’t cure an infection?

Peru Bound 4 by Mark & Andrea Busse, on FlickrTechnically, the hand sanitizers target virions, not viruses.  Virions are the form of the virus that exist outside of our body.  They have a special protective coat that keeps them healthy in the outer world – a naked virus is very delicate.

When the virion enters the body and uncoats itself (like people take off their coat when entering inside your house) then it’s known as a virus.  After uncoating, the virus no longer conceals its weapons such as its proteins (kind of like knives and guns) and DNA or RNA (sort of like high-tech computer weaponry). Using these weapons, it attacks and takes over cells in the body, holding them hostage until your body’s police force (the immune system) is able to step in and stop it.

What a great houseguest, no?

So, to answer your question: hand sanitizers target the coat of the virion. They cut and shoot holes into the coat. But if the virus has invaded your body (your home), these same chemicals aren’t very useful because they have already de-robed and made their way inside your cells. Plus, you couldn’t inject a hand sanitizer anyway because today’s sanitizers are made from concentrated alcohol that would kill you if put in the blood.

But think about it.  If an intruder is outside of your home, it’s very easy to arrest them or shoot them without harming you.  But if they have taken you hostage, and are holding you at gunpoint so to speak, it’s much harder to stop such a complex situation. It’s also very difficult to harm the intruder without also harming you by accident. This is one of the key reasons why so many antiviral medicines taken by mouth are either ineffective or cause many side-effects.

So hand sanitizers can be useful for virus protection but are not designed for hostage crisis situations.

Answer by Artem Cheprasov

Question from @pstni via Twitter

Article by Artem Cheprasov

March 10, 2014

Dr. Artem Cheprasov was born in St. Petersburg, Russia. He then moved to the U.S. when he was a little boy. So no, he is not a spy. Or is he? He finished his studies in veterinary medicine at the top 10% of his class, conducted research, and discovered a cool mathematics algorithm; but we cannot confirm this as both Washington and Moscow have refused to comment on this matter either because he really is a spy or more likely because they have no idea who he even is.


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Hair and nails grow after death: why and for how long?

This does not happen. It is simply not true that hair and nails grow after death.

Does hair grow after death?After a person ceases to be among the living, their life, and energy supply (i.e. the blood) no longer flows throughout the body. That’s because the heart has stopped pumping it and because the blood transforms from a runny liquid into non-functional paste-like sludge that stays in one place.

Therefore, because the cells that produce your hair and nails do not receive a fresh supply of nutrients, including oxygen, they can no longer power the important cellular processes responsible for life and growth. Consequently, cells in the body begin to die within seconds of a person’s death.

The reason hair and nails “grow” after death is because of an illusion. Hair and nails are very hardy, non-living, structures. As the living tissues and cells around the hair and nails begin to dehydrate and break down, the skin shrinks back, making it seem like the hair and nails have become longer in relative proportion.

Just think of it this way: in the winter, go outside and place a stick vertically in some snow. The stick can be the hair or nail. The snow around it is like the living tissue around the hair and nail. As the snow around the stick “dies” or melts away, the stick will “grow” longer and longer despite actually staying the same exact size.

Answer by Artem Cheprasov

Question from Eugene Pirko

Image source: winterofdiscontent, on Flickr

Article by Artem Cheprasov

February 24, 2014

Dr. Artem Cheprasov was born in St. Petersburg, Russia. He then moved to the U.S. when he was a little boy. So no, he is not a spy. Or is he? He finished his studies in veterinary medicine at the top 10% of his class, conducted research, and discovered a cool mathematics algorithm; but we cannot confirm this as both Washington and Moscow have refused to comment on this matter either because he really is a spy or more likely because they have no idea who he even is.


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