For many potential entrée animals this [sound of lion roar] is one of the scariest sounds around. Scientists long thought the lion’s distinctive roar was due to thick layers of fat inside the vocal cords.
What does an "entree animal" mean?
Animals that will be the dinner (entree) for another animal.
Confusingly, in the USA an entrée is the main course; elsewhere it is the first course or starter (AE appetizer).
See also this Similar Thread.