Guinea pig power

Pachacamac: Guinea pigs, those Andean rodents so beloved by European children as pets, are more than strokeable, tailless rats – they have uses. Many. The ingenious people of the rural town of Pachacamac, outside Lima, are using the furry fellas to light their homes, cook their food, grow their veggies, power their televisions and, this is Peru after all, line their bellies.

Winter veggies growing with guinea pig manure

We visit Casa Blanca, the delightful home of semi-retired professors Carmen Felipe-Morales and Ulises Moreno (who appropriately got his PhD at Ithaca (Cornell)), two plant physiologists turned agronomists, who run a sustainable agriculture programme at the nearby National Agrarian University of Molina. Their villa, set in gardens bursting with flowers, trees, vegetables and birdlife, is also a lab where they carry out their tech-transfer work or, as Ulises puts it: “We bring a lot of clever scientists here, who have spent their time studying plant genetics or researching different biochemical pathways for fertilisers, and we say ‘how about seeing right now if we can make a difference to farmers in Peru?’”

Carmen and Ulises get the most from their 'cuy' (guinea pigs)

To this end, the couple have developed different potato varieties optimised for soil and climate types and several types of organically produced fruits and cereals. Naturally, they are using their combined century’s worth of academic experience to produce these seemingly instant results, but they are keen to make the point that Peruvians can and should ‘do it for themselves’ rather than waiting for saviours from the developed world or burying researchers in labs away from the communities that could benefit from new findings.

Up to 1000 guinea pigs are kept in allocated pens

Taking up one wall of their plot is a low-roofed shed housing almost 1000 guinea pigs (Carvia porcellus) in numbered, regularly compartmented enclosures. They burble and chatter, whistle and purr as they eat their specially enriched food of plant waste matter.

They are fed a nutritionally enhanced diet

School children on an organised visit are swarming the shed, cooing over the fluffy creatures, while Carmen entertains them, answering their ‘is it a boy or girl cuy?’ questions by picking one up and manipulating its nether regions to reveal a tiny pink penis. The kids like that very much.

Carmen shows us it's a 'boy' cuy

The guinea pigs are part of a remarkable living factory that supplies the fuel and fertiliser for all the couple’s other projects. The small dry pellets that the rodents poo out are fed into a bio-digester that Ulises adapted from a Chinese model – water is added and bacteria metabolise the slurry – to produce methane gas and a dark brown liquid plant nutrient, which he calls ‘Caca Cola’.

The bio-digester. Poo goes into the right-hand hole, biogas rises from the middle hole and the left-hand one produces the liquid plant feed

It’s an incredibly efficient, non-smelly process (it’s buried underground) that produces enough gas for the family’s use (plus more) and litres of the growth hormone to sell.

Ulises shovels in the rodent poo

The 1000 guinea pigs produce 3 tonnes of poo a month – who knew they shit so much? – but the couple only uses 200 kilos of this in the bio-digester. The rest is aerobically degraded in a mixture of silage to produce high quality organic compost for their use and to sell.

The rest of the guinea pig excrement is mixed with agro-waste and decomposed to make compost. Bamboo 'breathing' tubes are planted in the piles to oxygenate the process

Even so, they produce 3 cubic metres of methane a day. Plus, 50 litres a week of the caca cola, which they sell for 2 soles (65 cents) per litre – the industrially produced equivalent goes for 150 soles (US$ 50) per litre.

A very high quality compost is produced

A pipe goes from the fermenting excrement mixture to small shed, ending in the inner tubes of tractors and truck tyres. Once a tyre is full, it can be attached to the household gas line, from which the family runs gas-powered lightbulbs, gas stoves and, excitingly, an electric generator. The household powers its electric devices from computers to TV using guinea pig shit.

The couple uses the compost to grow experimental crop varieties

“My message to the people of Peru is: don’t blame your poverty. Transform your poverty using affordable technologies and processes to improve your quality of life and happiness,” Ulises says, tucking into ice-cream made from fruit grown using cuy shit and frozen with cuy-shit-power.

The technique works well but, despite teaching people how, Ulises is frustrated by the lack of people who are using it

And the animals? Well, after they’ve pooed and copulated to the ripe old age of 18 months or so, they are sold for a good price to Lima’s upscale restaurants and organic food stores. Mmm, rico!