Posts Tagged 'cats'

More odd melanism

I’ve muttered about melanism on here before and the other day at Beijing zoo I saw a nice, if unusual example that seemed worth showing. Black jaguars (like this one) and indeed leopards are pretty common in zoos and turn up in the wild from time to time, it doesn’t seem to be an especially rare mutation, or one that is especially detrimental (hence it keeps coming back). However, even the blackest of these cats typically still show the underlying pattern of spots or rosettes through the otherwise black coat.

In this case through there is a fairly clear and gradual transition from the black background on top to a paler and more naturally orange / golden to white on the belly, with the rosettes naturally sanding out better too. This is not something I’ve been before, and while the animal is hardly half-way between being melanistic and normal, it’s definitely not fully black either. Colour patterns and things like albinism and melanism (or even amelanism) are complex and a wide variety of mutants and variations are seen, but given the number of black leopards and jaguars I’ve seen over the years, this was a pleasant surprise to see.

Why biology is hard – the physics of cats

The little thought experiment that forms the basis of this post is taken from Professor Charles Marshall via Musings regular Corwin Sullivan and aptly demonstrates why an awful lot of biology is really quite hard to study when compared to the other sciences (most notably physics and chemistry).

Let us consider a standard billiards table (though bar billiards should be recognised as one of the greatest games ever, it is perhaps not the best for this example, and a cannon billiards table might be even better, but so obscure I doubt even many British readers have come across one, anyway…) and on this table lets put three balls in a row evenly spaced across the width of the table. Now, hit each ball in turn gently, aiming straight down the table as evenly as possible (that is, try to make each shot have the same power and no spin). What will happen to the balls? Continue reading ‘Why biology is hard – the physics of cats’

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