When you hear the term euthanasia in reference to animals, you think of the process used to end an animal's suffering by placing it into a painless, permanent state of sleep. Today the term euthanasia is used to justify the murders of innocent animals all over the world. Animals should only be euthanized if they are in pain or suffering. Unfortunately, most dogs euthanized throughout the year are not aggressive or suffering from any disease (The Humane Society of the United States). Most animals are euthanized due to overpopulation in animal shelters. Euthanasia is a cruel and unnecessary practice that is not in the animal's best interest. There are many different types of euthanasia used by animal shelters to put down animals. The most popular type of euthanasia is called intravenous injection, which is a poison containing sodium pentobarbital. This poison is injected into the heart or leg without painkillers. The animal is put to sleep and in some cases wakes up when it feels pain and starts struggling and arguing with the vet. More injections may be necessary depending on the weight of the animal. This process is also used for animals euthanized due to illness or injury. Another process is called a gas chamber. The animal is placed in these gas chambers and "usually screams and cries until it falls asleep" (Chrysta). Carbon dioxide is emitted and the animal will die in about twenty minutes. Many animal shelters believe this is an inhumane way of killing animals and are against it. But there are still animal shelters in the United States that still use this method. Neck displacement or known as cervical dislocation is another f...... middle of paper......y of Puppy Mills." Animal Euthanasia and the Cruelty of Puppy Mills. Booksie, February 11, 2013. Web December 10, 2013. “Common Questions About Animal Shelters: The Humane Society of the United States.” RSS, May 3, 2013. Web November 21, 2013. Coraggio, G.. Web. November 21, 2013 “PETA’s Euthanasia Policy: Global Animal Excessive?” Why Do We Euthanasia.” Peta, March 21, 2013. Web. November 21. 2013. “Pet Overpopulation: The Humane Society of the United States.” RSS The Humane Society of the United States, nd Web November 14, 2013. The Humane Society of the United States, November 21 2013. .