Carl Zimmer, the science journalist has an article up at Corante (whatever that is), which takes an interesting look at Toxoplasma gondii. This is the parasite that cats have that is the reason pregnant women are not allowed to handle kitty litter.

The toxoplasma parasites live in the gut of cats, producing eggs which are excreted and are picked up by other animals in their surrounds, like rats. But to complete the life cycle the toxoplasma must return to the host, the cat. For this to happen the rat must be eaten by the cat. But generally rats have a fear of cats, which Carl Zimmer reports has been shown by experimentation:

The scientists studied the rats in a six-foot by six-foot outdoor enclosure. They used bricks to turn it into a maze of paths and cells. In each corner of the enclosure they put a nest box along with a bowl of food and water. On each the nests they added a few drops of a particular odor. On one they added the scent of fresh straw bedding, on another the bedding from a rat’s nests, on another the scent of rabbit urine, on another, the urine of a cat. When they set healthy rats loose in the enclosure, the animals rooted around curiously and investigated the nests. But when they came across the cat odor, they shied away and never returned to that corner. This was no surprise: the odor of a cat triggers a sudden shift in the chemistry of rat brains that brings on intense anxiety.

But when the rats were infected with the toxoplasma (which gets into their brains) their behaviour was different:

The scent of a cat in the enclosure didn’t make them anxious, and they went about their business as if nothing was bothering them. They would explore around the odor at least as often as they did anywhere else in the enclosure. In some cases, they even took a special interest in the spot and came back to it over and over again.

The toxoplasma actually infected the rats brain to make them less scared of cats, so that they are more likely to be eaten by cats, allowing the toxoplasma to return to the cat-host and reproduce in its gut.

Now this toxoplasma also infects humans, and half of all people are estimated to be infected. We also know that half of all people are dog people, and half are cat people. How did that half become cat people? I think we know now. They are all infected with toxoplasma gondii.

In related news, there are lots of these parasites that effect animal behaviour, for example, so as to make ants climb high to release their spores:

One of the interesting things I have found on youtube is the music videos that fans make for their favourite musicians. For example, Sufjan Stevens is a popular artist nowdays, but his earlier works came out with no music videos for them. In this case, fans of the musician have put time and effort into making their own music video versions. And these are surprising well done. Have a look and judge for yourself.

The Red One is a recent digital camera produced by the Red Digital Camera Company. The camera shots at greater than HD and at up to 120 frames per second, which allows the production of great slow-mo video.

As an example, here is a clip shot on the Red One.

skate – shot on red #1347 – 120 fps from Opus Magnum Production on Vimeo.

The music is ‘It’s Alright’ by Bang Gang and the site appears to be the Trocadéro in Paris.