We cannot see all the animals who have been born in the animal world. Because some animals are living under the earth like worms. Some animals are living in the water.
One day the Blessed One took up a little bit of soil in his fingernail and asked the monks, “Which is more: the little bit of soil in my fingernail or the great earth?” The monks replied, “Bhante the great earth is more.”
Our Supreme said, “Likewise when animals pass away, the amount of beings reborn as humans in their next life is extremely few. The majority of beings are born in bad destinations. If you are born in the bad destinations like animal world, Titan world, Hell world or ghost world, there is no practicing of the Dhamma, there is no practicing of what is righteous, no doing of what is wholesome and no collecting of merit.”
That’s why our Supreme Buddha said, when beings pass away, the majority are born in bad destinations. So my dear Dhamma friends, have a strong determination not to do evil deeds from your body, speech and mind.
You can read this sutta here on SuttaFriends.org.
We learned many things like what are the bad destinations hell, animal world, titan world, and ghost world. Even beautiful animals suffer like they can’t talk and know how many bad merits they have done. So the animals in this world don’t have a happy life but do suffer instead.