Density in swarms may be as high as 30,000 krill per 35 cubic ft (1 cubic m). Some swarms appear to be segregated by age or sex. Usually rise to the surface at night to feed, remaining deeper during the day. Occasionally will surface during the day, for unknown reasons. An anti-predation strategy is that, upon being disturbed, some individuals will suddenly molt while fleeing, leaving behind their exoskeletons as decoys. This may be effective when fleeing predators such as seabirds that target individual krill, but offers no protection against highvolume feeders such as whales.
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