I do not think that humans are just another animal. One huge difference between humans and animals is that animals are not capable of sin. Animals do not have the Knowledge of Good and Evil. A dog might choose to dig through the trash knowing that he will be scolded if his owner notices. And when his owner does notice he may cringe in anticipation of the scolding. But he doesn't have an understanding that obedience to lawful authority is good and willful disobedience is evil. His doggie brain just desired the hot dog in the trash more than it feared his owner's scolding.
The fact that animals cannot sin is one of the reasons that many people say they prefer animals to people. Your pet does not hold grudges or refuse to be seen in public with you when you're not dressed well enough. Your pet will forgive more than seventy times seven times. In whatever capacity your pet is capable of love, it loves unconditionally.
Your pet is also simple. He does not have a creative mind that allows him to write piano concertos or paint portraits or understand general relativity. A dog is content to be a dog. He doesn't feel driven to reach new heights of doggie achievement, where no dog has gone before. The simplicity of animals is another reason we might prefer them to humans. Your dog is not going to have an emotional meltdown because you accidentally burnt the toast this morning. Your cat isn't going to feel unloved if you refuse to share your feelings.
Animals act is predictable ways. Steve Irwin always said that if someone gets attacked by an animal it's the human's fault because the animal is just doing what animals do. We can't say that of humans. There is no formula for predicting human behavior. While the college students of the Stanford Prison Experiment quickly fell into a set of predictable roles based on their individual personalities and the surrounding environment, in larger sample sizes we find that counterexamples, however few, always exist. From St. Maximilian Kolbe taking the place of a man to be executed at Auschwitz to Fr. Emil Kapaun routinely giving away his starvation rations in a Korean POW camp, we find that somehow it is possible to be the exception. Human beings are capable of rising above. Under inhuman conditions, not everyone is reduced to operating on base instincts and animalistic urges.
One might think that insisting that humans are just like other animals will make us better stewards of the Earth, because we will feel more solidarity with the animals. Knowing that what makes human beings different from animals is the root of all evil, we may think that rendering humans as just another animal will free us from the pride that leads to every kind of conflict. We may think that likening ourselves to animals will bring greater peace by freeing us from our inhibitions and eliminating shame and guilt. But there is a major problem with this kind of thinking: Human beings are not just like animals. I may wish that it were true, but wishing doesn't make it so.
Human beings were given the gift of intellect in order to understand and love God, who is Truth and Love. We were given creative abilities to produce masterpieces that glorify God. We were given free will in order to choose good, while remaining fully capable of choosing evil. We were given such freedom in order to work tremendous good. Humans beings are not simple and predictable, which is wonderful when our unpredictability is ordered toward God. Unfortunately, we do not always choose good. We do sin. To treat human beings like just another animal is to ignore sin and to pretend that we don't have the Knowledge of Good and Evil. It's a fantasy world where I cannot be held accountable for my actions because I am simply responding to my natural urges. It is excusable for a dog to act simply by responding to his natural urges. However, as mom used to say, you and I should know better.
This great gift of being created in the image and likeness of God with the ability to create and to produce ever greater achievements should be embraced and cultivated. With such a gift comes great responsibility. "From everyone who has been given much, much will be demanded; and from the one who has been entrusted with much, much more will be asked." --Luke 12:48 Such a gift should be used for creative rather than destructive purposes. Instead of glorifying the animals and degrading the humans, we human beings need to be called higher. We must demand that human beings do not behave like animals but, rather, strive to recognize our full human potential. We need repentance and conversion and the hope of becoming what we were created to be: Perfect, like our Heavenly Father is perfect.
Or, from a more secular humanist perspective:
"When we treat man as he is, we make him worse than he is; when we treat him as if he already were what he potentially could be, we make him what he should be."--Johann Wolfgang von Goethe