Fibers for fuel

And now for something completely incoherent: a ramble about pikas, horned lizards, ruminants, biofuels and genetic sequencing.

Pikas

I recently posted a video about pikas. Like their fellow lagomorphs, rabbits and hares, pikas can live on indigestible grasses thanks to the bacteria in their caecal pouches. A big part of their body mass is devoted to digestive systems, yet unlike ruminants lagomorphs can't pump their food backward and forward to take advantage of the work done by the gut bacteria. So they have to eat their food more than once.

Horned Lizards

Horned lizards also have proportionally large digestive systems, because they eat ants. And that need for a big digestive system is believed to be one reason horned lizard bodies are so spiky. As DigiMorph explains it:

"Ants are small and contain much indigestible chitin, so large numbers of them must be consumed. Hence an ant specialist must possess a large stomach for its body size to process a lot of material. [...] the stomach occupies a considerably larger fraction of the animal's overall body mass [...] than do stomachs of all other sympatric desert lizard species. Possession of such a large gut necessitates a tank-like body form, reducing speed and decreasing the horned lizard's ability to escape from predators by flight."

The full article is well worth reading. It has a lot more interesting info on horned lizards, including the fact that some of them give live birth. I have read elsewhere that the live-bearing species tend to live at higher altitudes, where it would be difficult to keep eggs sufficiently warm.


Ruminants

Ruminants such as cattle can live on grasses. Their food goes back and forward through several stomach chambers while bacteria break down plant fibers.


Biofuels


Cosmos Magazine reports on genetic sequencing of cow gut bacteria aimed at discovering how to break down cell fibers more efficiently. The techniques of the researchers were somewhat gruesome: they inserted nylon sacks of switchgrass through holes in cows' skin directly into their stomachs. The method was considered necessary because the bacteria of interest could not be cultured.

Once they had enough bacteria they removed the nylon sacks and analyzed the bacterial DNA, looking for genes whose products aid in the breakdown of cellulose.

"It is hoped that this research can speed up the process of breaking down switchgrass into sugars including glucose and xylose to be fermented into ethanol."