A Muslim considers most animals to be deserving of a certain level of respect as creatures. He shows mercy to them due to the mercy of Allah upon them. He also adheres to the following manners with respect to them, which are part of the etiquettes that Islam encourages Muslims to fulfill:

1. A Muslim feeds or gives water to an animal if he finds it hungry or thirsty. This is based on the Messenger’s sallallaahu `alayhi wa sallam ( may Allaah exalt his mention ) statement: ”There is a reward (for serving) everything with a moist liver (that is, every living creature).” [Ahmad]

2. A Muslim should have compassion and mercy towards animals. The Prophet sallallaahu alayhi wa sallam ( may Allah exalt his mention ) said: “Whoever does not show mercy will not be shown mercy.” [Al-Bukhaari and Muslim]
He sallallaahu alayhi wa sallam ( may Allah exalt his mention ) said in another narration: “Have mercy toward those on the Earth and The One above the Heavens will have mercy on you.” [At-Tabaraani]

The Prophet sallallaahu alayhi wa sallam ( may Allah exalt his mention ) himself set the best example in this regard. When he sallallaahu alayhi wa sallam ( may Allaah exalt his mention ) saw a group of people using a live animal for archery target practice, he sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) said: “May Allah curse the one who uses any creature with a soul as a target.” [Muslim]

Once a bird was distressed because someone had taken its young from her nest. Allah’s Messenger sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) then said: “Who has distressed this one because of its baby? Return its baby to her.” [Abu Daawood]

3. The Muslim must be kind to the animal, even when he is about to slaughter it. Allah’s Messenger sallallaahu alayhi wa sallam ( may Allah exalt his mention ) has said: “Verily, Allah has prescribed excellence in all things. Thus, if you kill, kill in a kind manner. If you slaughter, slaughter in a kind manner. Each of you should sharpen his blade and spare suffering to the animal he is slaughtering.” [Muslim]

4. A Muslim should never torture an animal by any means of torture, such as beating it, making it carry more than it can handle, mutilating it, or burning it by fire. The Prophet sallallaahu alayhi wa sallam ( may Allah exalt his mention ) also prohibited the tying down of animals until they die. Allah’s Messenger sallallaahu alayhi wa sallam ( may Allah exalt his mention ) once said: “A woman entered the Hell-fire because of a cat that she tied down. She neither fed it nor let it free to eat the insects of the earth until it died.” [Al-Bukhaari]

Allah’s Messenger sallallaahu alayhi wa sallam ( may Allah exalt his mention ) once passed by an anthill that had been burnt to the ground and he sallallaahu `alayhi wa sallam ( may Allaah exalt his mention ) said: “It is not becoming that anyone should punish by fire except the Lord of the Fire.” [Abu Daawood]

However, it is permissible to kill harmful animals, such as voracious dogs, wolves, snakes, scorpions, rats, etc. This is based on the Prophet’s sallallaahu alayhi wa sallam ( may Allah exalt his mention ) statement: “Five noxious or harmful animals are to be killed whether or not one is in the state of pilgrimage: the snake, the speckled raven that has whiteness either on its back or stomach, the rat, the voracious dog and the kite (a bird similar to a hawk).” [Muslim]

It is also confirmed from Allah’s Messenger sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) that he cursed the scorpion and killed it. [Al-Bayhaqi]

Other related matters:
1. It is allowed to brand grazing animals in their ears for some overriding need. The Prophet sallallaahu alayhi wa sallam ( may Allah exalt his mention ) was seen branding, by his own hand, the camels given in charity. As for other than camels, sheep, goats, and cows, it is not allowed to brand them. The Prophet sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) saw a donkey branded on his face and said: “May Allah curse the one who branded that (donkey) on its face.” [Muslim]

2. One must recognize the right of Allah concerning his animals by paying the Zakah due on them if they are from the animals concerning which one must pay Zakah.

3. One must not become so preoccupied with animals or playing with them that one disobeys Allah, or does not remember Allah properly. Allah has said, (what means): “O you who believe! Let not your properties or your children divert you from the remembrance of Allah.” [Quran 63:9]

Allah’s Messenger sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) stated concerning horses: “A horse may be kept for one of three reasons. For one man, it may be a source of reward, for another, it may be a source of living and yet for another, it may be a sinful burden. As for the one for whom it is a source of reward, he is the one who keeps his horse for the sake of Jihaad in Allah’s cause (i.e. fighting); he ties it with a long rope in a pasture or in a garden. So whatever its rope allows it to eat will be regarded as good, rewardable deeds (for its owner). And if it breaks off its rope and jumps over one or two hillocks, even its dung will be considered among his good deeds. A horse is a shelter for the one who keeps it so that he may earn his living honestly and takes it as a refuge to keep him from following forbidden means. (The third is) a horse is a sinful burden for him who keeps it out of pretense and show and with the intention of harming Muslims.” [Al-Bukhaari]

These are, in general, the etiquettes that a Muslim should adhere to with respect to animals, out of obedience to Allaah and His Messenger sallallaahu `alayhi wa sallam ( may Allaah exalt his mention ) and in adherence to what the Islamic law has ordered him… the Sharee’ah of mercy… the Sharee’ah of general goodness for all creatures, be they human or animal.