Purpose of Animals
It is my understanding that God created everything for a reason, and yet it seems that creatures such as ants, flies and mosquitoes only do bad – spoiling food, spreading bacteria and diseases. Should we try to preserve these species, or maybe we should just eliminate them all as a nuisance?
The Aish Rabbi Replies:
King Solomon wrote in Proverbs, "Go to the ant, you sluggard; see its ways and grow wise. Though there is neither officer nor guard nor ruler over her, she prepares her food in the summer and stores up her food in the harvest time." (Proverbs 6:6)
The Midrash explains that King Solomon was warning lazy people to learn from ants since ants never stop working. Throughout their lives they continuously store up food – in fact more food than they could ever eat! Likewise, man should also seek to do mitzvahs. Just as the ant "prepares her food in the summer," so too we should seek to do mitzvahs all the time we are alive. And just as the ant enjoys her food at "harvest time," so too we will enjoy our reward in the World to Come. (Midrash – Devarim Rabba)
The Talmud writes: "If the Torah had not been given, we could have learned modesty from the cat (because it relieves itself in private), prohibition of theft from the ant (since they do not take food belonging to another ant), fidelity from the dove (because they only have one mate), and good manners from the rooster who first sweet-talks and then mates." (Rashi, Talmud – Eruvin 100b)
Elsewhere the Mishna writes, "Be bold as a leopard, and swift as an eagle, and fleet as a hart, and strong as a lion, to do the will of thy Father in heaven." (Ethics of our Fathers 5:20)
And this is only talking about the lessons one can learn from animals. When we think about the enjoyment and fun we can also have from owning pets – or even going to the zoo – animals take on an even more important place.
As for what we learn from a mosquito, I am sure you will be able to find at least one redeeming feature that they add to God's creation. (Some have suggested that he provides food for a variety of birds.) But I wouldn't wait until he lands on your arm to start pondering such a question...