Unfortunately the descriptions of Hysterocrates leave much to be desired, &
when combined with the fact that there are many similar species, this leaves
us collectors in a state of confusion. There are no keys currently available
on differentiating the various species.
The spider passing as "hercules" is most likely a few large specimens of gigas, that have reached 8" in legspan (not 10"). It is not clear if the hatchlings from huge mothers will also grow as large (environmental factors may be a strong influence).
The true H. hercules has a different range from where these gigas are imported (Cameroon). It is unlikely that any true hercules are in the USA, & few would be found in European collections. Hercules itself has been recorded with an 8" legspan, so it may not be any larger than these big gigas. Also, the Sao Tome Hysterocrates scepticus, may reach 8" or even bigger, & those hatchlings are available from several sources in the USA currently.
All Hysteros seem to need the same requirements: deep, moist soil to allow for burrowing, moderate ventilation, a full fresh water bowl, a cork slab to hide under, high humidity, & temps ranging from daytimes of 90 summer days, to as low as 60 degree winter nights. If you let them cool down, make sure that you warm them up during the day so that they can digest any food in their gut. They are a tropical rain forest genus, dependent on moisture & secure retreats.
Hysteros are one of the best burrowers in the spider world, & can tear through thin plastic & window screening with ease. Keep this is mind as you set up cages. Little silk is spun, so that they can usually be observed in their burrows, with the aid of a flashlight.
This is a fascinating genus, with females killing prey for their young, & hatchlings are capable for living together for 6 months or more in a sweater box (or acquarium), if well fed (making maintenance a breeze). They are very familiar with standing water & puddles, & may even hunt tadpoles & minnows in the wild (I have had juveniles totally submerge themselves in deep waters bowls, when disturbed). They are as close to an aquatic tarantula as I have seen so far. Studies of their behavior should prove interesting. They produce round portable sacs, unlike most other baboon spiders. Females almost never destroy their sacs. Adults will often stand & stridulate when disturbed. They handle mice almost as easily as they do crickets.
All of the "new world" collectors I know have a big Hysterocrates or two.
Mike Troll's Tarantula Page: Another care sheet by the one and only Rick Blauman!
ATS: Go to "Articles Online"; "ATS Eggsack"; "Florida Bites!" by Chris Edwards
Lelles Tarantula Page (English version): A picture and a good intro