I see, that explains the tiger and the deer.

6 seconds sound clip from the Forbidden Planet (1956) movie soundboard.

You can hear this line at 00:50:37 in the Blu-ray version of the movie.

Quote context

[...]

- In times long past, this planet was the home of a mighty and noble race of beings which called themselves the Krell.

- Ethically, as well as technologically, they were a million years ahead of humankind...

- For in unlocking the mysteries of nature, they had conquered even their baser selves.

- And when, in the course of eons, they had abolished sickness and insanity and crime and all injustice they turned, still with high benevolence, outward toward space.

- Long before the dawn of man's history, they had walked our Earth and brought back many biological specimens.

- I see, that explains the tiger and the deer.

- The heights they had reached.

- But then, seemingly on the threshold of some supreme accomplishment which was to have crowned their entire history, this all but divine race perished in a single night.

- In the 2000 centuries, since that unexplained catastrophe, even their cloud-piercing towers of glass and porcelain and adamantine steel have crumbled back into the soil of Altair-4, and nothing absolutely nothing, remains above ground.

- What were they like?

[...]