TED-Ed: Pruney fingers: A gripping story - Mark Changizi

The video explores why fingers get pruney when wet, suggesting they function like rain treads to improve grip. Historical observations noted that nerve-damaged patients didn't get pruney fingers, leading to hypotheses about their purpose. The video compares pruney fingers to rain treads and river networks, suggesting they channel water away to enhance grip. Experiments confirm that pruney fingers improve grip in wet conditions, indicating an evolutionary advantage for primates in wet environments.

What observation in the 1930s led scientists to question the purpose of pruney fingers?

• Patients with nerve damage did not get pruney fingertips.

• Pruney fingers were linked to vitamin deficiencies.

• Pruney fingers were found to be more common in children.

• Pruney fingers were observed only in cold climates.

How do pruney fingers function similarly to rain treads on car tires?

• They increase the surface area for better grip.

• They channel water away to reduce slipping.

• They provide insulation against cold temperatures.

• They enhance the aesthetic appearance of fingers.

What analogy is used to describe the structure of pruney fingers?

• A network of highways

• A tree with branches

• A web of spider silk

• A series of tunnels

What did experiments reveal about the effectiveness of pruney fingers in wet conditions?

• They slow down the ability to grip objects.

• They have no effect on grip in wet conditions.

• They enhance the ability to grip wet objects.

• They make it harder to release objects.

Why might pruney fingers have been evolutionarily significant for primates?

• They were a sign of good health.

• They provided protection against predators.

• They were useful in wet, grip-heavy environments.

• They helped in climbing dry trees.