Cruelty to animals refers to treatment which causes unacceptable suffering or harm to animal. The definition of "unacceptable suffering" varies. Some consider only suffering inflicted for sadistic reasons to be cruelty to animals, whereas others include the suffering inflicted for other reasons, such as producing fur or meat, or in the animal-testing industry. Many people regard cruelty to animals as a major moral issue.
Psychological studies have shown that individuals who take pleasure in inflicting harm on animals are more likely to do so to humans. This should not be confused with people who simply kill or harm animal for practical purposes (such as food, lab experiment, animal husbandry). One of the known warning signs of certain psychopathologies, including anti-social personality disorder, also known as psychopathic personality disorder, is a history of torturing pets and small animals, a behavior known as zoosadism. According to the New York Times, "[t]he FBI has found that a history of cruelty to animals is one of the traits that regularly appears in its computer records of serial rapists and murderers, and the standard diagnostic and treatment manual for psychiatric and emotional disorders lists cruelty to animals a diagnostic criterion for conduct disorders.  "A survey of psychiatric patients who had repeatedly tortured dogs and cats found all of them had high levels of aggression toward people as well, including one patient who had murdered a young boy." 
Cruelty to animals is one of the three components of the MacDonald Triad, indicators of violent antisocial behavior in children and adolescents. According to the studies used to form this model, cruelty to animals is a common (but not universal) behavior in children and adolescents who grow up to become serial killers and other violent criminals.
It has also been found that animal cruelty in children is frequently committed by children who have witnessed or been victims of abuse themselves. In two separate studies cited by the Humane Society of the United States (HSUS), roughly one-third of families suffering from domestic abuse indicated that at least one child had hurt or killed a pet.
The animal welfare and animal rights movements represent two different responses to the issue. The animal rights movement holds that animals have rights, as humans do, including the right not to be used against their own best interests for human gain, and that humans should stop treating animals as commodities. The animal welfare movement believes that the use of animals for human ends is justified in some instances, but within this view, seeks to end unnecessary suffering and improve animals' treatment.
Either way, humane education is widely viewed as a potential solution to the problem of animal cruelty. By reaching children early in life, and focusing on instilling respect and compassion for animals, the goal is to stop potential abusers before they start
Laws against animal cruelty
There are many laws that let animal abuse happen. Many jurisdictions around the world have enacted statutes which forbid cruelty to some animals; for example, see Cruelty to Animals Acts in the United States. These statutes provide minimal requirements for care and treatment of animals, but do not require optimal treatment or mandate kindness or love. They require that animals be provided shelter, food, water and medical treatment and that animals not be tortured, or killed in an inhumane manner. Traditional practices, even if controversial (such as treatment of rodeo and circus animals or medical research or animals deemed pests) are usually excepted from the operation of the law.
In a few jurisdictions, notably Massachusetts and New York, agents of humane societies and associations may be appointed as special officers to enforce statutes outlawing animal cruelty, see the Massachusetts statute and the New York statute. Brute Force: Animal Police and the Challenge of Cruelty by Arnold Arluke is an ethnographic study of these special humane law enforcement officers.
It is to be noted, however, that in the USA ear cropping, tail docking, the Geier Hitch, rodeo sports and other acts perceived as cruelty in many other countries are in fact condoned. Penalties for cruelty are minimal, if pursued.
In Australia, many states have enacted legislation outlawing cruelty to animals. Whilst police maintain an overall jurisdiction in prosecution of criminal matters, in many states officers of the RSPCA and other animal welfare charities are accorded authority to investigate and prosecute animal cruelty offences.
Most jurisdictions simply depend on law enforcement officers who may not be knowledgeable in the area or assign it a high priority. Spectacular stories about grave atrocities and animal hoarders are mainstays of local TV news reporting, but most offences concern lack of adequate shelter or food and similar mundane deficiencies in animal care.
In the United Kingdom, cruelty to animals is a criminal offence and one may be fined or jailed for it for up to five years. One notable case occurred when a group of students placed a hedgehog within a microwave in the late 1990s. Bestiality is also banned, and one may be prosecuted for running over a dog or a similarly sized animal, although not a cat. The RSPCA, founded in 1824 as the SPCA, was the first animal welfare society in the world.
In Japan, animal cruelty laws historically were lax and seldom enforced. The 2002 Japan animal cruelty case lead to the first animal cruelty felony conviction in Japan. The case awakened a movement to strengthen animal cruelty laws.
In Mexico, animal cruelty laws are slowly being implemented. The Law of Animal Protection of the Federal District is wide-ranging, based on banning 'unnecessary suffering'. The law prohibits conducts from dissection for students in high school or earlier years, to negligence of the owner in providing medical attention to an animal that needs it. Similar laws now exist in most states. However, as many laws in the country, this is blatantly disregarded by much of the public and authorities; animal protection legislation is gaining relevance very slowly.
:8) best of luck!~