Out on the grassy expanse, babookaris will move in a group about 30 strong, their long tails sticking up. Occasionally, one stops and raises its head above the tops of the grass stems. The face is almost humanlike, and is round with red naked skin, framed in a lion-like mane.
The deep rainforest that once grew here was home to a number of New World monkey species. There were large monkeys that lived mainly on the forest floor, agile monkeys that primarily swung about in the branches and tiny, acrobatic that leapt from treetop to treetop. The fertile habitat could sustain such variety. Now the rainforest has gone, replaced by an unchanging stretch of grassland. As it shrank to islands of trees and, finally, to isolated stands, those species of New World monkey which could not adapt became extinct.
One species not only survived, but flourished. The uakaris, that were found in the northwestern Amazon Basin, were some of the most adaptable of Quaternary monkeys. It was an omnivore, eating anything from insects and fruits to leaves, seeds and even smaller vertebrates. It was at home in the trees, but just as comfortable on the ground. Such generalism left it well positioned to adapt to the retreat of the rainforest. The uakaris were able to abandon their arboreal way of life and take to living on the grasslands which were spreading across the Amazon Basin.
This is not the first time that rainforests have been replaced by grasslands. Back in the Late Neogene period, a similar phenomenon occurred in Africa, brought on by a drop in atmospheric humidity levels. Then, the ancestors of baboons left the trees and took to dwelling mainly on the ground, becoming more quadrupedal in the process. Now, in South America, the descendants of the uakaris have done exactly the same. They have evolved into babookaris.
Like all primates, the hands of a babookaris are prehensile, that is, they are adapted for grasping or gripping. Now, though, they are more often used for walking than for swinging through trees. The babookari is essentially a larger version of its uakari ancestor, down to its hairless red face. It is about 18 inches (46 centimeters) high at the shoulder and weighs 40 pounds (18 kilograms). One major difference is the babookari's tail. The uakari was unusual in that it was a New World monkey that did not possess a long, prehensile tail. Its descendant has evolved a long tail, but this is not like a muscular, extra limb used for swinging about in trees. Instead it is a tall, inflexible rod, about 32 inches (81 centimeters) long with a tuft of hair at the end. This tail is used for signaling across the plains.
Being a social animal, the babookari needs signaling devices such as its long tail, colored chest, colored bottom and colored face. The only way a monkey can live on the open grassland is as part of a troop. A large group of 30 or so individuals can quickly scour a wide area of savannah for food and can cooperate in defense against certain predators.
Since it came down from the trees, this monkey has gained a great deal of intelligence. It has retained enough dexterity in its hands to be able to weave hollow, spherical fish traps from grass stems. Babookaris deploy these basket-like structures in the shallow seasonal rivers that wind their way across the plain. Fish is an excellent protein supplement for these omnivorous primates. When on fishing trips, the troop stays together. Some individuals work the traps, while the others are on the lookout for danger. The older individuals are the more skillful at making the baskets. The younger individuals watch them and learn how it is done.
On the open grassland, danger can come in many shapes and sizes. Almost certainly, however, it will come on long legs, like the carakiller.