Shape change behavior by mesopelagic animals

Abstract

In situ observations in Monterey Bay and elsewhere revealed a common behavior pattern among certain species living at mesopelagic depths between 200 and 800 m. When these animals were presented with threatening stimuli, they responded by curling their elongate bodies into circular shapes. They maintained this posture, hanging motionless in midwater, until the danger had passed. This behavior was strongly associated with dim light and occurrences were rare in well‐lit shallow depths, at depths beyond the penetration of sunlight, and at night. This behavior is interpreted as a case of protective mimicry, in which these animals change their appearance to resemble medusae as unpalatable models.

Key words:

• Behavior
• mimicry
• mesopelagic animals

Notes

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