Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Pheromes - more than communication

Easy to read overview of pheromones, a variety of chemical molecules that help sperm cells find (ie, move in the direction of) egg cells, male animals find females and vice versa, as a signal for a male fish to deposit his sperm over recently released eggs, as an alarm signal for an entire group of animals, as a signal for a male hamster to mate with a female, as a territorial mark, etc, etc. This reference provides the general reader with some background in a variety of physiological and zoological areas. Although not fully explored, the existence of pheromone-guided actions, provides an effective mechanism for creatures, both ancient and modern, with limited nervous systems to exhibit a variety of complex behaviors.