Amazingness

Wyndham and Comber Estate, Redcar Street, London, SE5

It turns out that grass is actually rather difficult to eat. One reason is that the blades contain a gritty compound called silica, the same stuff that is found in sand, and used to make glass. It is a very hard, abrasive substance, and functions as a line of defence against being eaten, as it wears down the teeth of animals that chew it.

But of course we know that lots of animals do eat grass – horses, cows, sheep, buffalo and gazelles to name a few – so how do they deal with the wear and tear on their teeth on a daily basis, considering the fact that if their teeth become totally worn down, they’re unable to keep eating and will die as a result?

Simple! Through the evolution of long teeth, which continuously grow (or erupt) throughout their lifetime; thus, despite being constantly worn away, they are perpetually replaced. Brilliant!

Therefore, in order to find out if pigeons eat grass, it is necessary to ask whether they have long teeth. Do they? No. (Incidentally, pigeons don’t have any teeth, and they do eat grass seeds).

However, this is not the end of the story. It’s all very well for animals to have evolved long teeth in order to chomp and chew to their heart’s content; but grasses don’t want to be munched to death. Moreover, they aren’t munched to death. But why not?

Grasses (and there are a lot of different and very important grasses – rice, wheat, bamboo, sugar cane, little tufts of common urban grass like this one here) grow from the base of their stems, as opposed to growing from their tips which is the case in other plants. This ingenious adaptation, that evolved in response to grazing animals, means that grasses can be feasted upon, or mown down, yet they’re still able to keep growing.

I like the symmetry here: teeth and grass both wear each other down, so both have developed a similar adaptation – to keep growing out from their respective bases. The result: they are both able to successfully flourish in each other’s company.