Aerenal Beastmaster( Races of Eberron, p. 105)
As an elf of Aerenal, you consider baboons sacred animals and they serve you obediently.
ability to acquire new animal companion, Elf, region of origin Aerenal,
You add the baboon to your list of animal companions (see page 268 of the Monster Manual), and can use the summon nature's ally I spell to summon a baboon instead of a monkey. A druid with a baboon animal companion has his druid level treated as three higher for the purpose of determining the baboon's modified statistics, bonus tricks, and special abilities. A ranger with a baboon animal companion has an effective druid level equal to one-half his ranger level +3, instead of one-half his ranger level.