The Raoellidae, previously grouped within Helohyidae, are an extinct family of semiaquatic digitigrade artiodactyls in the clade Whippomorpha.

An exceptionally complete skeleton of Indohyus from Kashmir suggests that raoellids are the "missing link" sister group to whales (Cetacea).

δO18 values and osteosclerotic bones indicate that the raccoon-like Indohyus was habitually aquatic.

However, it is still unclear if Indohyus primarily fed on land or in water.

It is hypothesized that cetaceans evolved from ancestors similar to Indohyus and later fully adapted to aquatic life.