Deer

The Deer is the symbolic herd-huntable creature in all Age of Empires games.

Age I
The Deer (or back then, the Gazelle) was a standard animal that ran around the map when hunted. it had 8 hp (2 spears) and ran away when you came nearby. Also provided 150 food for the player that caught it.

Age II
The Deer is now called a deer, keeping with the shift from the middle-east to Europe as the civilisations changed. The deer still had 150 meat and ran away when hunted, but hunters could now haul meat away in much larger lumps (35 meat/trip).

Age III
The Deer has reached its final iteration, and now has 20 hp (2 shots/1 with Blunderbuss, thanks to Villager attack bonuses), and due to improved meat storage methods has had its meat content boosted up to 400 meat, making it a more appealing food source than eg the Berry Bush.