How many pairs of tentacles do banana slugs have, and what are their general functions?

• A. One pair; used for balance.
• B. Two pairs; the upper pair bears eyes for light detection.
• C. Two pairs; the upper pair bears eyes for light detection and the lower pair is used for touch and smell.
• D. Three pairs; used for locomotion.

Answer: (C)

Banana slugs have two pairs of cephalic tentacles. The upper pair bears eyes at their tips, giving light detection to help the slug distinguish light from dark and navigate its surroundings. The lower pair is used for touch and chemosensation (smell), allowing the slug to feel its environment and sense chemical cues from food and surfaces. The slug’s movement relies on a muscular foot, not the tentacles, so describing the tentacles as for locomotion isn’t accurate. So the best description is two pairs with the upper pair for light detection and the lower pair for touch and smell.