Wild guinea pigs anyone?
When we first picked up our little guinea mates Milo & Oreo, one of the first things I thought was “I wonder what these little guys eat in the wild”. And so began my gradual (and somewhat maddening) descent into the realm of the wild guinea pig!
Turns out, there’s a fair amount of research – if you know where to look. For the last few weeks, I’ve been dusting off old research papers and contacting expert guinea pig professors from all over the world.
I wanted to write this article because I felt that understanding guinea pigs in the wild would help us all understand our domesticated friends a little bit more – and that can only be a good thing!
Please note all these facts refer to Cavia Apera (Brazilan Guinea Pigs), the widely accepted ancestor of the domestic guinea pig.
So, without further ado, let’s begin with our list of surprising facts.
1. Their homes are huge, between 0.63 – 1.1 km
I guess a kilometer is a lot bigger than your guinea pig cage, right?
In the wild, cavies cover a lot of distance every day and tend to establish themselves within home ranges once they’ve found a good one. These ‘homes’ were measured to be 880 ± 217 m2. Pretty impressive for a small rodent. Within these ranges, they live in small family groups and keep well away from their neighbours.
And while cavies don’t defend strict territorial boundaries, if an intruding male comes too near… he’ll be chased off!
2. They spend most of their time hiding
Well… except when they’re sunbathing.
Wild guinea pigs seem to spend most of their time in hiding and only come out from the protective cover of dense, tall vegetation to forage in more open grassland (and occasional sunning).
Foraging occurs mainly in the morning and evening (sound familiar, guinea parents?). This reflects the ‘crepuscular’ activity pattern of wild guinea pigs, with main activity phases being from 0700 – 1100 and 1730 to 2000.
3. They have mortality rates upto 50%
It’s not easy being a wild guinea pig.
As (soft, furry) prey animals, they are hunted by a wide variety of predators.
Raptors, caracara, grisons, opossums and domestic cats all hunt guinea pigs in the wild – with grisons and cats being the most successful. Even Boa constrictor have been observed swallowing wild cavy.
In fact, life is so hard, one study that observed a group of 60 wild cavies for 6 months found that only half (50%) of the animals they tagged survived the study period.
4. They can run as fast as 6 meters per second
Last time I tried to pick Milo up – I blinked – and he was gone. To the other side of the room!
Domestic guinea pigs are fast… but wild guinea pigs are even faster.
One study found maximal escape speeds of adults averaged 4.12 m/sec, with peak velocity of 6.0 m/sec. Interestingly, newborn young were able to run at speeds up to 2.55 m/sec and reached adult levels when only 20 days old.
This works out to be around 16 times body length per second, with very young animals reaching even higher relative speeds – up to 20 times their body length per second.
To put this into perspective, this is the same ‘body length per second‘ ratio as a cheetah! In other words, if you made a wild guinea pig the same size as Usain Bolt – it would run at a startling 99 mph, 4x faster than the Olympian himself!
Although bare in mind they are only able to sustain these super fast speeds for short periods of time (which makes perfect sense when you’re running from the claws of hawk into a bush).
Such remarkable rodent running skills are otherwise only observed in hares.
5. They can jump as high as 60cm
Everybody knows it’s hard work being a scientist.
Well… sometimes. For a period 5 months in 1997, a team of researchers were employed to the task of randomly jumping out to surprise wild guinea pigs – and measuring how high they jumped (yes really).
OK, there was a little bit more to it than that. The guinea pigs were first trapped inside a cardboard box with the top cut off – with an open bottom on exposed natural soil. They were then left to their own devices for a number of hours, to see when they would decide to jump out.
The scientists repeated this experiment multiple times, with increasingly higher cardboard box sides. Heights tested were 20, 30, 40, 50, 60, and 70 cm.
Only once this voluntary jumping test was completed, did the team take turns to jump out (I heard a rumor they were wearing masks disguised as grissons) and surprising the cavies – Boo!
This confirmed that, yes, wild guinea pigs in fact jump significantly higher when scared.
On average cavies jumped 60 cm in a free jump from a standing start – which was 1.5x more than the voluntary jump.
Note: No wild guinea pigs were harmed in the production of this study.
6. They go where the grass grows greenest
Guinea pigs love grass, everyone knows that.
But wild cavies really need it – they are largely graminivorous (grass eating) In fact, if there’s none around, they’ll vacate the area and find a new home that does have plenty of the green stuff.
One study found that as soon as the delicious open grasses they were feeding on grew to over 40cm (enough to cover the cavies and protect them from predators) the wild guinea pigs ‘moved in’ to this area, completely abandoning the thorny shrubs they were living in before.
Until, of course, the grass was cut short again – at which point they moved back! (See: Can Guinea Pigs Eat Grass?)
7. They use cryptic defense techniques
No, this doesn’t mean your guinea pig is a secret code breaking expert.
In zoology terms, ‘cryptic’ means ‘serving to camouflage an animal in its natural environment’.
Wild guinea pigs achieve this by freezing in their tracks as soon as they hear a predator approaching. They employ this strategy when hiding in dense vegetation, which effectively means they become invisible – due to the density of the shrubs around them.
Guinea parents will recognize this trait in their pets, which lives on in domestic guinea pigs.
8. Many wild guinea pigs are monogamous
Wild cavies live in stable social groups consisting of 1 adult male, between 1–3 adult females and their unweaned offspring. Although male cavies can build these small ‘harems’ of upto 3 females, this occurs in only 33% of observed groups.
The other two thirds are good old fashioned male-female pairs!
Sadly, in C. Aperea this doesn’t appear to be true monogamy, but rather a mating system known technically as ‘female-defense polygyny’. In other words, these wild guinea pigs are faithful not through choice – but from lack of it.
That said, a new species of wild guinea pig discovered in 2002, C. Galea was found to be truly monogamous!
Who said romance was dead?
9. Their houses have toilets
Wild cavies don’t dig into the ground, but instead burrow complex mazes of surface tunnels within the dense vegetation.
These tunnels are 3 to 5 in wide and have latrine areas beside the trackways – where piles of bean-shaped droppings can be seen, as can piles of cut grass stems.
If you ever needed proof that your guinea pig likes it when you clean out his cage – here it is.
10. They make 10 distinct noises
Just like their domestic cousins, wild guinea pigs use sound to communicate socially and to avoid predators.
One study investigated these acoustics in depth and found ten distinct call types:
teeth-chattering, structurally variable contact calls, whines and squeals, a scream, an alarm whistle, an almost exclusive pup-isolation whistle and tweet calls.
Sound familiar?
The similarity of this repertoire to that of our domesticated friends shows just how similar these two closely related species still are – and that the richness of this communication system is not a product of domestication.
More likely, it is thought to be associated with a relatively complex social life and other ecological factors.
Final Thoughts
Well, I hope that was interesting!
Guinea pigs – be they wild or domesticated – are intelligent creatures and much still remains a mystery about the intricacies of their social systems and tunnel networks. Since they remain hidden in foliage so much, these aspects have to date been extremely difficult to study.
Let us hope that future research will uncover more about these things… so that we may learn new ways to enrich the lives of our little friends and become better guinea parents!
References:
- Effects of domestication on bio-behavioural profiles: a comparison of domestic guinea pigs and wild cavies from early to late adolescence
- The Rich Acoustic Repertoire of a Precocious Rodent, the Wild Cavy Cavia aperea
- Ontogeny of running performance in the wild guinea pig (Cavia aperea)
- Social System and Spatial Organization of Wild Guinea Pigs ( Cavia aperea ) in a Natural Population
- Role of diet selection in the use of habitat by pampas cavies Cavia aperea pamparum (Mammalia, Rodentia)
- Diversity of social and mating systems in cavies: a review
- Monogamy in a new species of wild guinea pigs (Galea sp.)
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Mammals of the Neotropics, Volume 3: Ecuador, Bolivia, Brazil By John F. Eisenberg, Kent H. Redford, Fiona Reid, 1989
Image Licenses:
Zoo Jihlava image: (C) Milan Korinek, Feature Image by Bernard Dupont (creative commons); Costanera image by Donald Hoburn (creative commons); Munich image by Diego Delso, delso.photo, License CC-BY-SA
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