EPOW - Ecology Picture of the Week

Congo Giant Earthworm

Unidentified earthworm species
Family Eudrilidae or Acanthodrilidae*
Democratic Republic of the Congo, Africa

Explanation:  Some things seem to grow to gigantic proportions in central tropical Africa ... such as trees, snails, water bugs, beetles, spiders, seeds, moths, millipedes, and termite nests!  This week we encounter the giant earthworms of the Congo.

I happened upon this young fellow who was gathering giant earthworms and washing them in a stream, to be used for fishing.  Presumably the fish will be giant too.  

Several colleagues and I encountered this fellow and his catch while we were riding motorcycle trail bikes along remote footpaths paralleling the Lukeni River in roadless Salonga National Park, central Democratic Republic of the Congo ... but that's another story. 

These earthworms were simply immense, although the South African giant earthworm has been said to grow to 22 feet (6.7 meters) long!  Other giant earthworm species have been reported from Oregon and Washington in the U.S. (2-3 feet long), and from Australia (3 feet) and New Zealand (4.5 feet).  

I don't know what species is represented in my photos here, or even if it is scientifically documented from the area.  

 
Earthworms provide key ecological functions of churning soil, ingesting bacteria, and especially providing nutrients from their waste products.  As they burrow, they aerate the soil and improve its structure, helping other invertebrates, fungi, and plants beneficial to soil health to persist.  Earthworms are literally ground-movers and provide much of the rich farmland soils of temperate zones of the world. 

And they're great for fishing, too!

*Acknowledgment:
     My thanks to EPOW reader Csaba Csuzdi D. Sc., of the Systematic Zoology Research Group of HAS and Hungarian Natural History Museum, Budapest, for identification of the possible family of this organism, correcting my previous identification error ("prob. Lumbricidae").  Lumbricidae is a Holarctic family, whereas Eudrilidae is native to Africa and Acanthodrilidae is Gondwanean.  I was unable to procure a specimen, and thus any further identification is uncertain.