function SmartPlantEater() {

this.energy = 30;

this.direction = "e";

}

SmartPlantEater.prototype.act = function(view) {

var space = view.find(" ");

if (this.energy > 90 && space)

return {type: "reproduce", direction: space};

var plants = view.findAll("*");

if (plants.length > 1)

return {type: "eat", direction: randomElement(plants)};

if (view.look(this.direction) != " " && space)

this.direction = space;

return {type: "move", direction: this.direction};

};

function Tiger() {

this.energy = 100;

this.direction = "w";

// Used to track the amount of prey seen per turn in the last six turns

this.preySeen = [];

}

Tiger.prototype.act = function(view) {

// Average number of prey seen per turn

var seenPerTurn = this.preySeen.reduce(function(a, b) {

return a + b;

}, 0) / this.preySeen.length;

var prey = view.findAll("O");

this.preySeen.push(prey.length);

// Drop the first element from the array when it is longer than 6

if (this.preySeen.length > 6)

this.preySeen.shift();

// Only eat if the predator saw more than ¼ prey animal per turn

if (prey.length && seenPerTurn > 0.25)

return {type: "eat", direction: randomElement(prey)};

var space = view.find(" ");

if (this.energy > 400 && space)

return {type: "reproduce", direction: space};

if (view.look(this.direction) != " " && space)

this.direction = space;

return {type: "move", direction: this.direction};

};

animateWorld(new LifelikeWorld(

["####################################################",

"# #### **** ###",

"# * @ ## ######## OO ##",

"# * ## O O **** *#",

"# ##* ########## *#",

"# ##*** * **** **#",

"#* ** # * *** ######### **#",

"#* ** # * # * **#",

"# ## # O # *** ######",

"#* @ # # * O # #",

"#* # ###### ** #",

"### **** *** ** #",

"# O @ O #",

"# * ## ## ## ## ### * #",

"# ** # * ##### O #",

"## ** O O # # *** *** ### ** #",

"### # ***** ****#",

"####################################################"],

{"#": Wall,

"@": Tiger,

"O": SmartPlantEater, // from previous exercise

"*": Plant}

));