Assertion: hippo's calf | /r/HasProperty | single
Facets:
Source sentences:
text: A female hippo will give birth to a single calf every two years.
text: After copulation and conception, hippos have a gestation period of around eight months, they will generally deliver a single calf every two years, and the females give birth underwater.
text: A mother hippo typically gives birth to a single calf, but they have been known to give birth to twins in very rare cases.