Not really, although it sometimes goes by other names. The anus is the part of the body of most animals that excretes waste products in solid (or mostly solid) form. Animals will also have a urethra through which liquid wastes are expelled. Birds have neither; instead, they have a "cloaca", from the Latin word for "sewer". (That's why bird mess is runny and splatters on your car; it's all mixed together.)
But no matter what you call it, there has to be an excretory organ to eliminate wastes; otherwise, the animal will die.
Gas is passed this way through the anus.
If you inject urine into your anus, you could very well get an infection. This is not guaranteed, as it is your own bodily fluids, but it is possible to get an infection.
It is possible but difficult and far easier to get someone else to do it for you.
In humans, no, not unless the person was born with a birth defect.
Pregnancy can only occur if sperm fertilizes an egg in the uterus. The anus is not connected to the reproductive organs where fertilization takes place, so it is not possible to get pregnant from anal intercourse.
Possible causes of black dots around a dog's anus may include anal gland issues, flea infestation, or skin infections. It is important to consult a veterinarian for proper diagnosis and treatment.
Possible reasons for a dog's anus pigment change include natural aging, genetics, hormonal changes, inflammation, infection, or underlying health conditions. It is important to consult a veterinarian for a proper diagnosis and treatment.
With the aid of a mirror, then yes, it's quite easy.
It is possible that your cat is experiencing anal gland issues, which can cause clear fluid to leak from the anus. It is important to consult a veterinarian for proper diagnosis and treatment.
If you have to ask this question, you probably shouldn't be having intercourse. The answer is no. You cannot get pregnant by semen being introduced into your anus. However, your anus is so close to your vagina it is possible for semen to be "accidentally" introduced into the vagina so hopefully you're using protection and plenty of it.
If you have Hemorrhoids, they can be expelled upon voiding. This is the muscle around the anus and not an intestine.
The anus is merely a sphincter, it cannot digest or absorb anything. It is possible to introduce substances through the anus into the large intestine, which does have the capacity to absorb water or substances dissolved in water; it does not have the capacity to digest anything, however. Digestion takes place in the stomach and the small intestines, not in the large intestines.