Assertion: dolphin's predator | /r/HasProperty | polar bears
Facets:
Source sentences:
text: The main predators of seals are killer whales, polar bears, leopard seals, large sharks, and human beings.
text: Other threats include natural predators (polar bears and killer whales), contamination of rivers (as with Polychlorinated biphenyl (PCBs) which bioaccumulate up the food chain) and infectious diseases.