Assertion: narwhal's tusk | /r/HasProperty | an indicator of fitness
Facets:
value: as a mate
type: MANNER
Source sentences:
text: The tusk is an indicator of fitness as a mate," Laidre said, adding that scientists haven't been able to genetically show that males with longer tusks are more reproductively successful because it's difficult to biopsy (take a tissue sample) from a free-ranging narwhal.