Carol Farneti, Natural Science Photos 



ized they were gone, I reasoned that they 

 had journeyed to the next fig tree, which I 

 knew was about a thousand feet along the 

 river trail. I moved quickly along the trail, 

 making little noise since the leaves be- 

 neath my feet were wet from rain that had 

 fallen earlier in the day. 



But I wasn't the only one walking 

 quickly and silently along the river trail. 

 As I rounded a bend, I suddenly stood face 

 to face with a large male jaguar. We were 

 less than three feet apart. My headlamp 

 temporarily blinded him, and he blinked 

 five times. I moved slightly off the trail to 

 give him the right of way. At the sound of 

 my movement, the jaguar bounded into 

 action, but — I noticed in a daze — away 

 from me, back into the jungle. I listened as 

 he continued to move into the distance. 

 Suddenly, I was afraid. My heart raced, 



Common in the open Chaco forests of Paraguay, nocturnal great 

 homed owls, left, are capable of carrying off small monkeys. There, 

 the otherwise noisy owl monkey, below, moves more cautiously and 

 quietly than in the rainforest. 



Ctiarles Janson 



and I decided to give up monkey watching 

 for the evening. Instead, I visited each tent 

 of sleeping researchers, warning them that 

 a jaguar was in the neighborhood. The 

 next day, we were impressed by the large 

 size of the footprints, but we never saw the 

 jaguar again. He had apparently moved on 

 to another part of his large territory. 



Most of my evenings were less event- 

 ful, and after a year, I had accumulated 

 basic data about the two species. In both, 

 territory size ranged from seventeen to 

 thirty-four acres. The distance the owl 



monkeys traveled in one day was 2,100 

 feet on average; the titis moved an average 

 of 1,950 feet. The average group size of 

 both — five animals — was also similar and 

 included an adult male and female, one 

 adolescent, a juvenile, and an infant. The 

 adults are monogamous, and their off- 

 spring remain with the group until they are 

 three, at which time they disperse, usually 

 in the rainy season. Finally, as with most 

 primates, both species ate a combination 

 of fruits, leaves, flowers, and insects. 

 But the two species also differed in 



47 



