Re: Fleas and AAH

Herb Huston (
7 Jul 1996 22:30:10 -0400

In article <>,
Keith Norris <keith@GECKO.BIOL.WITS.AC.ZA> wrote:
}In article <keith.52.002586F0@GECKO.BIOL.WITS.AC.ZA> you wrote:
}: Paging through the introduction to Desmond Morris' "The Naked Ape" I came
}: across this interesting piece:
}[quotes hacked]
}: My question is this - surely an aquatic ape would not have had a problem with
}: fleas as they could not have survived the long periods in water postulated by
}: the AAH?
}Hmm... possible reason behind this could go something like:
}We have lost our fur anyway, right? Apart from the head hair, and pubic
}hair, and the hairier chests of males, (which I am inclined to think came
}later after a northward migration anyway). So, unless we were already
}clothed by this time, the fleas would be unable to cling to us.
}So we need somewhere where they can live and grow and not get caught, and
}crawl out and know we would be there to bite.
}But, if we had lost our fur, we are more likely to need comfortable
}bedding, right? And the fleas are used to living and breeding in the
}bedding anyway, so that's not a problem.
}So, since we are hairless, all the fact that we have fleas tells us is
}that we stayed in the same place long enough to allow fleas to breed in
}our bedding.

Bingo! Fleas parasitize animals that have home bases.

}Although this seems in opposition to many of the theories opposing the
}AAT, which would fit better the pattern of a nomadic lifestyle, I see no
}reason why a creature hunting berries or whatever during the day cannot
}return to a predefined base, particularly if it were in a nice spot and
}with comfortable beds prepared. I thought gorillas did this anyway,
}(sleeping in 'nests'), but I may be mistaken.

Chimpanzees and gorillas sleep in different locations each night.

}However, it does tell us that if we were aquatic, then we were probably
}fixed to one home base for fairly extended preiods of time.
}: The fleas would not have had time to evolve into this species
}: there-after (I don't think). This goes hand-in-hand with a very early
}Since I think the AAT says that we were aquatic for a good deal
}less time than we have since been non-aquatic, the fleas could be a later
}addition. After all, as you say,
}: host-parasite interactions and co-evolution are [...] extremely rapid
}I'm curious, though. I have heard of cat fleas and dog fleas, but never a
}human flea before. Is this because they are uncommon in the UK?

The human flea is _Pulex irritans_, but it can also parasitize dogs, hogs,
some other mammals, and poultry. It's reddish brown and about 2-3 mm in
length and has a lifespan of up to 18 months, being able to live for up to
6 months without food. Like its principal host it enjoys a worldwide

-- Herb Huston