The other tribes should be in the vicinity (in tribal stage) or in space stage mouse over certain planets and on the box that appears there should be a small fire symbol in the top left/right hand corner if it is planet inhabited by tribes.
No tribes will come till you have allied the first one or attacked it.
In that stage you can only give gifts by clicking on their food from only very aggressive tribes then you can click how many creatures of yours to throw flowers and to bring the gift. But you can't give gifts to friends.
If you mean spore the game, there could be humans, made by other users. Though our solar system is in spore, there are no official humans (made by the creators of the game) in spore.
Spore creatures cannot be permanently invisible, there's an ability called sneak that lets you temporarily be invisible to other creatures other then your own.
he hated other tribes
Spore Galactic Edition doesn't come with the Creature Creator disc. However, the Spore Creature Creator is included in the game, along with all the other creators, on both versions of the game.
if you are talking about the iroquois tribe , it worked with 5 other tribes but sometimes they work with other tribes
No, but you can "talk" to other players...
spore
Spore (PC) Spore Creatures (DS) Spore Hero (Wii) Spore Hero Arena (DS) Spore: Creepy and Cute Expansion (PC) Spore: Galactic Adventures (PC) Spore Creature Keeper (Not released yet)
Spore (PC) Spore Galactic Adentures (PC) Spore Creature Creator (PC) Spore Creature Keeper (PC) Spore Creepy and Cute (PC) Darkspore (PC) Spore Hero/Spore Hero Arena (Wii, Nintendo DS) Spore Creatures (Nintendo DS, IPhone) Spore Origins (IPhone)
Preschool (2-6): Spore Creatures, Spore Hero Arena, Spore Creature Creator Normal kids (6-8): Spore Creatures, Spore Hero Arena, Spore Creature Creator Preteens/Tweens (8-12) Spore, Spore Creature Keeper, Spore Hero, Spore Creepy and Cute, Spore Galactic Adventures Teenagers (12-18): Darkspore Adults (18-22): Darkspore