"A cat and a horse eat."
Translation:En kat og en hest spiser.
"æde" is mostly used for animals, perhaps the wilder ones. Youngsters also tend to use "æde" instead of "spise" nowadays.
"spise" is used for humans as well as animals and is by far the most common translation for "eat".
A quick search in KorpusDK shows that "æde" is used 12,3% of the time, where "spise" goes 87,7% of the time.
You can also use "æde" as an insult if you think someone has bad tablemanners. Han æder som et svin=he eats like a pig.