Assertion: narwhal's trait | /r/CapableOf | show disproportional growth
Facets:
value: often
type: TEMPORAL
value: in individuals of the same age
type: OTHER
Source sentences:
text: The researchers said the results provide the best evidence to date that narwhal tusks are used to fight off other males or attract mates, as traits determined by sexual selection often show disproportional growth in individuals of the same age.