Calculate zodiac signs

/**
 * Calculation. Zodiac
 *
 * @param int $year Year
 * @return str
*/
function get_animal($year){
 $animals = array(
 'Rat', 'Ox', 'Tiger', 'Rabbit', 'Dragon ', 'Snake',
 'Horse', 'Sheep', 'Monkey', 'Chicken', 'Dog', 'Pig'
 );
 $key = ($year - 1900) % 12;
 return $animals [$key];
}

echo get_animal(1990); // Horse
echo get_animal(2010); // Tiger