1. “The Case of the Monkeys that fell from the Trees”
By:
Susan Quinlan

2. Why are howling monkeys falling from trees and dying?
Problem
Why are howling monkeys falling from trees and dying?

3. Research Howling monkeys eat only plants
Howling monkeys are skilled, nimble characters
They leap 10 ft. or more between tree limbs and almost never fall
Scientists examined dead monkeys and found no sign of disease or parasites
They had not starved

4. Research cont.
6. Some of the monkeys had been feeding on poisonous leaves 7. They were able to digest or tolerate poisonous plants

5. Scientists believed certain trees were killing the monkeys.
Hypothesis
Scientists believed certain trees were killing the monkeys.

6. Experiment
*For 12 months, scientists would observe habits of howling monkeys *They would collect samples of leaves from every tree the monkeys fed that day and leaves from nearby trees of the same species. *These were tagged with the tree, date, and time collected. *Leaves were dried in ovens, then packed in zippered plastic bags for later study

7. Observe, Record, Analyze
4 to 5 am – Monkeys awoke with roars and growls. They set off for bouts of feeding with periods of crawling, leaping, and climbing Midday – They settled down draping arms and legs over branches, slept with tails wrapped around branches to anchor them in place Late in the day – Monkeys stirred, climbed, and fed Sunset – Monkeys settled down for the night

8. Data How many minutes the monkeys spent sleeping, eating, and moving
They recorded which of the 1,699 individually numbered trees the monkeys slept in and ate from
They recorded which parts the monkeys ate – leaves, fruits, flowers, or stems

9. Analyzing Howlers ate new leaves whenever they could
They only occasionally ate fruits, flowers, or mature leaves
In certain trees, they stripped off leaves and ate only leaf stems
Howlers had not eaten leaves from just any trees in the forest
They rarely ate from most common tree species

10. Analyzing cont.
6. Most of the time they fed on few uncommon trees 7. Monkeys had eaten from only 331 of 1,699 trees 8. ¾ of time spent eating from only 88 trees 9. Data showed monkeys selected only certain tree species for feeding 10. Monkeys had not eaten leaves from all the trees of favored species 11. They ate leaves from only a few trees of most species

11. Analyzing cont.
11. They ate leaves from only a few trees of most species
12. Concentration of poisons not uniform among plants
13. Plants make varying amounts of poisons at different times of year
14. Of 331 trees eaten from, 104 were one stop trees – one monkey sampling

12. Conclusion
Falling monkeys were poisoned by eating from the wrong trees at the wrong time.

13. Findings
1. Howling monkeys had consistently selected the most nutritious, most digestible, and least poisonous leaves available 2. They ate only the leaf stems in trees where stems had fewer poisons than leaves 3. Howling monkeys are cautious, picky eaters in a forest filled with poisons