     c = @cellAt( x, y )
     ar = []
     f = (t) ->
-      d = Math.sqrt( (t.x - x)**2 + (t.y - y )**2 )
+      d = sqrt( (t.x - x)**2 + (t.y - y )**2 )
       ar.push [ t, d ] if d < t.radius
     f(t) for t in c.inhabitants
     for other in c.neighbors when other[1] <= @maxRadius

    @bodyColor = options.bodyColor || 'brown'
    @radius = options.radius || 5
    # intial orientation
    @angle = Math.random() * tau
    @velocity = [ 0, 0 ]
    @type = Animal
  defaultGenes: ->
    @mergeGenes super(), {
      auditoryRange: [ Math.min( @universe.maxDistance / 3, 20 ), 10, @universe.maxDistance / 2 ]
      visualAngle: [ .45, .1, .8 ]
      visualRange: [ Math.min( @universe.maxDistance / 2 , 30 ), 20, @universe.maxDistance ]
      g: [ 250, 1, 5000 ]
      jitter: [ .05, 0.01, 1 ]
      kinAffinity: [
        -2
        (t) -> -Math.max( .1, Math.abs(t.kinAffinity()) * 2 )
        (t) -> Math.max( .1, Math.abs(t.kinAffinity()) * 2 )
      ]
      foodAffinity: [
        10
        (t) -> -Math.max( .1, Math.abs(t.foodAffinity()) * 2 )
        (t) -> Math.max( .1, Math.abs(t.foodAffinity()) * 2 )
      ],
      maxAcceleration : [
        => @radius / 2

      babyThreshold: [ .4, .1, .9 ]
      plantAffinity: [
        .1
        (t) -> -abs(max( 1, t.plantAffinity())) * 2
        (t) -> abs(max( 1, t.plantAffinity())) * 2
      ]
    }
  plantAffinity: -> @genes.plantAffinity[0]
