"According to the chart on page 16 of OD&D volume 2, The Underworld & Wilderness Adventures, dragons can fly 24 five mile hexes per day. That's a 12 hex round trip."
This got me wondering about how much space campaign predators need, so I came up with a Size-based guideline. Then my OCD kicked in and I thought about tying in with the hex templates I use for my settings. All in all, a triumph of contrived realism, but I think you might get some mileage out of it.
Territory requirements are proportional to predator size. In other words, the amount of land necessary to sustain a predator increases as the monster gets bigger. I'm using the Chimera Size categories as the basis for determining territory. This roster assumes you're using 5-mile hexes, and that each is broken up into smaller, 1-mile sub-hexes.
In the table below, "Lair" refers to predator's "home base:" where it spends the majority of its time, raises its young, nurses its wounds, hides it treasure, and most actively patrols. "Radius" is the distance, in hexes, from the Lair to the edge of the monster's territory in all directions. Finally, "Area" is the total number of hexes that comprise the monster's territory. This is where the monster hunts, and the area in which it will feel threatened by (and pursue) trespassers.
Remember that hexes are 5 miles across and sub-hexes are 1 mile from end to end (based on our Hex Templates, an "atlas hex" is 25 miles wide).
25 hexes (1 atlas hex)
225 hexes (7 atlas hexes)
How this Helps
Use this approach when you create your camapaign maps (it's completely compatible with the Hex-based Campaign Design system). By spacing out territory for major predators (e.g., dragons, giants, dinosaurs, hydras, ogres, etc.) and settlements, you will avoid overpopulating a given area. As an added bonus, it shows you territorial borders, so you can predict where conflicts will erupt when living space gets tight. Consider some examples:
Diminutive: A smurf village occupies a single 1-mile sub-hex; Papa Smurf does not send patrols outside this area
Tiny: A swarm of giant bees lives in a big dead tree; they gather pollen from each of the surrounding 1-mile sub-hexes
Small: A rural halfling village and farmland spans an entire 5-mile hex; the sheriff's jurisdiction does not extend beyond the hex
Medium: A human town dominates a 5-mile hex; each of the surrounding hexes are actively patrolled and considered "settled"
Large: A lamia dwells in a hill cave; she roves the trails and tablelands in a 10-mile radius
Giant: A family of stone giants live in a mountain castle, from which they launch patrols in a 15-mile radius
Huge: A mighty and fearsome hydra lairs deep in the swamp; it ranges for food out to 5 hexes in every direction
Colossal: An ancient dragon dwells in the snowy mountains; it hunts for food (and adventurers) in a 35-mile radius
Granted, this approach doesn't mimic precise ecological reality, but it's a good starting point for figuring how much space certain creatures need to live. It also helps you plan more realistic encounters when your players decide to go hex crawling. Happy mapping!
Territory" is the monster's real estate, indicated by radius in hexes surrounding the Lair; this is where the monster hunts, and defines the boundary inside of which it will feel threatened by (and pursue) trespassers. Assuming that the Lair is at the exact centre of the Territory, "Range" is the linear distance from one end of the Territory to the other