Assertion: lemming's number | /r/CapableOf | fluctuate in four-year-cycles
Facets:
value: for unknown reasons
type: CAUSE
value: between extremes
type: LOCATION
value: wildly
type: DEGREE
Source sentences:
text: For unknown reasons, in four-year-cycles, lemming numbers fluctuate wildly between extremes, peaking to vast overpopulation before crashing to semi-extinction levels.