Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that only animals derive their nutrition by ingesting it?

Heterotrophs are the organisms which cannot prepare their food on their own like autotrophs instead are dependent on other mode to obtain the organic substances from the environment. This method is common in animal and fungi groups.

Although both fungi and animals are heterotrophs their mode of heterotrophic is different as fungi obtain organic substance b secreting many digestive enzymes which digests the complex biomolecules and the fungi obtain the organic substances whereas the animals swallow or ingest the material and then digests it.