Though this hypothesis was doubted by Nopcsa, it was adopted by the Danish researcher Gerhard Heilmann who in 1916 proposed that a quadrupedal Hypsilophodon lived like the modern tree-kangaroo Dendrolagus.
Iako je u tu hipotezu sumnjao Nopcsa, prihvatio ju je danski istraživač Gerhard Heilmann koji je 1916. godine predložio da je četveronožni Hypsilophodon kao današnji klokan penjač Dendrolagus.