Symbiotic Relationship with Fungus
Chris beside a Termite Mound
These monoliths dominate the cerrado in South America. There can be as many as 40,000 in one square kilometre. From the outside these things appear
entirely lifeless. In fact, you could sit down here alongside one and see nothing move all day. But living on the inside is perhaps the most important
animal in this entire ecosystem. They are the grasslands' secret weapon in the battle for nitrogen. Termites, half-blind distant cousins of cockroaches.
There are so many millions living in this grassland that their combined weight is far greater than that of all the mammals living here put together.
And yet you'd have no idea they were even here if they didn't build these huge mounds.
They build them as cooling towers, to keep the temperature of the colony on the inside at an optimum 30 degrees centigrade, and they are remarkably
efficient, normally accurate plus or minus a single degree. Not bad for a colony of primitive insects. But then, building these mounds all over the
landscape is the least of their accomplishments.
Because, one way or another, termites are fundamentally important to almost all life here. Especially
the strangest of all, the giant anteater. these animals are related to armadillos and sloths. They are part of a group called edentates, which basically
means "without teeth". But whilst armadillos and sloths do have rudimentary teeth, if you were to perform a dental examination of one of these guys, which
would be difficult because their mouth is so small, you'd find no teeth at all.
But it's not teeth he needs to unlock the termites' secret. If you look at its front feet you can see it's got these two huge claws on each one of them,
and they can break into just about any substrate. It also uses them for defence. It's said that if it's attacked by a larger predator, it'll stand back on
it's tail and lash out with those claws. He uses his tongue which is over 50 cm long, flicking it in and out at around 150 times a minute.
Giant anteaters eat 35,000 termites a day. Nevertheless, you could be forgiven for thinking that no matter how many they hoover up, or how quickly, they
could never sustain an animal this size. But they do. By weight, termites are the most protein-rich food that you can find. There is more protein in these
little insects than there is in beans, nuts, cheese, chicken, even roast beef. And what's interesting is that termites occur in ecosystems all over the
world, and whenever they do there are creatures like this that have evolved to feed exclusively on termites.
The reason termites are so rich in protein is all down to some very intimate relationships. The first is with the fungus. Deep within the mound, the
fungus breaks down dead grass to the termites can digest it. Not much else could eke a living out of this stuff. The second is more remarkable still. You
see, termites can obtain nitrogen directly from the air. And they achieved this through another symbiotic relationship, and even more intimate one. Because
living inside their digestive systems are amazing nitrogen-trapping bacteria, and it's this that gives termites their special powers.
So using the nitrogen they get from that bacteria, the nutrients they get from the fungus, they are able to turn this dead woody material into a productive
food source. This stuff, which is so low in nitrogen, so low in protein, they can come into edible protein, and that's how they can form these vast colonies.
The termite mound becomes a nitrogen hot spot. That's good for anteaters but also for all the surrounding plants and for all the other animals living here.
The incredible actions of termites nurture grasslands all over the world… Including Kenya's whistling acacia savanna.