Posts Tagged ‘technology’

Hamish the dog watching Inspector Rex

This Inspector-Rex obsessed canine is Hamish, who belongs to Sue, who recently got into an argument with a zoologist about whether or not her dog is really watching TV.

The zoologist argued that it’s not possible for dogs to see TV the way we do. Probably, he suggested, Hamish’s good sense of hearing is what’s working, and he is simply reacting to the sounds of animals he can hear on the TV. But is he?

Sue swears black and blue that Hamish does watch the screen – and in particular, enjoys animal programs. For one, he tries to interact with the animals on screeen, even with the sound off. And, when the program Inspector Rex is on, he will intently watch the main character, a German shepherd. If the dog leaves the screen then Hamish will get up and look behind the TV set to see where he’s gone.

So what’s going on here? Well, I scrounged around online and found that Sue’s anecdotes correspond well with other stories told by dog owners about their pets watching TV. There are lots of hilarious stories out there about of pets watching and reacting to animal shows.  But, it’s also true that not all dogs seem to watch TV or react to it in the same way.

Can dogs watch tv?

Well, yes. Back in 2003 some Hungarian scientists proved that dogs can watch TV, by testing whether dogs respond to videotaped images of their owners. They discovered that not only do dogs recognise their owners on screen, they also respond to non-verbal commands given on video. Dogs who couldn’t smell their owners – and smell is a pretty major sense for dogs interpreting the world – still obeyed the commands issued by video.

Then, more recently, some Australian researchers decided to check up on the old idea of all dogs having the same eye size and structure. They found out that different sized dogs do have different sized eyeballs. And, more excitingly, they also found that dogs have two completely different ways of seeing the world.

It turns out that some dogs have a visual streak – a high density line of visual cells that runs across the whole retina. This gives them a wide field of view and good peripheral vision. Other dogs just have a big cluster of visual cells right in the middle of their field of vision, called an ‘area centralis’. They can’t see much peripherally, but what they do see is in much higher definition.

This could help explain why some dogs chase after things, while others don’t. For dogs with a visual streak, a moving object will stay in their field of vision for a long time, enabling them to track it. Dogs with long noses tend to have this sort of vision, which could explain why they’re so good at hunting and catching – think hounds and beagles, or wolves.

For dogs with an area centralis, a moving object flashes quickly across their field of vision and is then gone. Short-nosed dogs are more likely to have this sort of vision, and it probably explains why they are less reactive to objects moving at speed – after a certain point, they just can’t see them. In Hamish’s case it could also explain why he’s so good at watching telly – having high def sight must make TV viewing a breeze!

Check out the original stories and, if you’re tired of Inspector Rex re-runs, maybe these will keep you amused:

Dogs explain the atom (video)

Science dog blog (tragically, it only has one post. About Tetris.)

Daily science news about dogs

A blog for dog lovers

A Mona Lisa smile?

One of these teeth has dental caries. Can you spot which one?

Memo to self: Teeth not as small and insignificant as they look! Last week, after a horrible toothache, I discovered that I have a rotten case of dental caries – aka tooth decay. Although you can’t see much from the outside, apparently one of my teeth has a big cavity and has to be pulled out. While I wait for somebody (anybody?!) to fetch the pliers, the pain is just excruciating. It feels a lot like somebody has driven a knitting needle through my cheek, which is making life utterly miserable. To make things worse, it seems the minute you say ‘teeth’, people start to tell you horror stories. From barbaric dentists to chronic infections, I’ve now heard so many tales of dental suffering and woe that it’s got me thinking. Why isn’t dental health covered by Medicare? And more importantly, how can something SO small in relation to the rest of our bodies cause such big trouble? Well, it turns out that overall well-being can be profoundly affected by dental health. Some types of decay, like the sort I have got, can be very hard to spot and can become quite advanced before anybody realises. Often you need x-rays to reveal what’s going on – and the tell-tale signs are dark patches inside the teeth. Out of interest, I got my dentist to send me the x-ray of my mouth. Can you pick which tooth is giving me all this trouble? First person to email me with the answer wins a prize! I’ve also had a cracking headache for 6 weeks and I wondered if this is connected to the tooth decay. It turns out that it is. As you might expect, the face, mouth and jaws are incredibly rich in nerve endings. There’s a major nerve that serves the mouth and jaw (the Trigeminal nerve) and also the front part of the head. This nerve is also stimulated when you eat really cold things, leading to the phenomenon of ‘Ice Cream Headache’! Not having had a cavity before, I wondered what had caused this one. Was it something I ate, such as the afore-mentioned icecream? Turns out the answer is Yes! It seems that cavities often form in places where food becomes trapped – in between teeth or in the ridges and troughs on top of the tooth. Here acid-producing bacteria can multiply, and these thrive particularly well when we consume a diet rich in sugars. Since prehistoric times, the incidence of tooth decay has increased with the introduction of more sugar into our diets. Interestingly, tooth decay leapt with both the introduction of agrarian (grain-based) diets centuries ago, and also with the invention of fizzy drinks in the 19th century. I don’t really eat or drink a lot of sweet foods but I do eat ‘natural’ sugars found in bread, fruit, wine, dairy products and honey. Over time all of these have probably contributed to my current plight. Which isn’t much of a consolation but at least I haven’t got teeth like some of these people So, little teeth can cause big problems. Like the one in my head right now. The good news is that this small bit of research has happily distracted me from the pain for, oh, at least 30 minutes! If you too need a distraction (or just something to get your teeth stuck into), you can read more here: Medline encyclopedia Dental Dude blog MedicineNet article on toothache And my particular favourite by a very good looking surgeon: Dr Kam’s dental blog In my next blog post, I’ll be watching TV with a small dog called Hamish. Fangs for visiting! Sorry, couldn’t resist…