r= and safe radius

can anyone tell me what the r= means in the wolves territory file and how it works please?

this is an example

<zone name="HuntingGround" smin="0" smax="0" dmin="0" dmax="0" x="2242.5" z="5662.5" r="157.5" d="2"/>

how does the safe radius work aswell please?

here's an example

event name="AnimalWolf">

<nominal>32</nominal>

<min>22</min>

<max>32</max>

<lifetime>180</lifetime>

<restock>0</restock>

<saferadius>200</saferadius>

<distanceradius>0</distanceradius>

<cleanupradius>0</cleanupradius>

<flags deletable="0" init_random="0" remove_damaged="1"/>

<position>fixed</position>

<limit>child</limit>

<active>1</active>

<children>

<child lootmax="0" lootmin="0" max="5" min="5" type="Animal_CanisLupus_Grey"/>

<child lootmax="0" lootmin="0" max="5" min="5" type="Animal_CanisLupus_White"/>

so the lower the r= number the closer you will have to get for the wolves to spawn in?

ok thanks for your help