Cloaca facts for kids

The cloaca is a special opening found at the back of many animals, especially those that live on land. Think of it as a single door for several important jobs! Through the cloaca, animals get rid of urine (pee) and faeces (poop). It's also used for reproduction, which is how animals make babies.

What is a Cloaca?

A cloaca is a common opening for the digestive, urinary, and reproductive systems. This means that waste products and reproductive cells all leave the body through this one exit. It's a very old feature in the way many animals are built.

Animals with a Cloaca

Many different kinds of animals have a cloaca.

• Amphibians: Animals like frogs, toads, and salamanders all have a cloaca.
• Reptiles: Snakes, lizards, turtles, and crocodiles use a cloaca.
• Birds: All birds have a cloaca.
• Monotremes: These are unique mammals like the platypus and echidna, found in Australia. They are the only mammals that have a cloaca.

How is it Different from Other Mammals?

Most mammals, including humans, are called "therian mammals." This group includes marsupials (like kangaroos) and placental mammals (like dogs, cats, and people). These mammals have separate openings for their body functions:

• An anus for getting rid of solid waste (faeces).
• Another opening for urine and for reproduction.

So, unlike animals with a cloaca, therian mammals have more than one exit at the back of their bodies.

Special Uses of the Cloaca

Some animals use their cloaca in surprising ways! For example, certain types of aquatic turtles can actually breathe underwater using their cloaca. They pump water into special pouches inside their cloaca. These pouches have thin linings that can take oxygen from the water, much like lungs do with air. This is called cloacal respiration.

Images for kids

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  Cloaca of a Red-tailed hawk

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  Cloacal opening in an Australian brushtail possum

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  Some aquatic turtle species can breathe underwater using a process known as cloacal respiration. In this process the turtles pump water into their cloacal orifice (labeled 1) by contracting muscles in their inguinal pocket. The water then travels to the cloacal bursae (labeled 2), which are a pair of internal pouch-like structures. The cloacal bursae are lined with long fimbriae (labeled 3), which is the site of gas exchange.

See also

In Spanish: Cloaca (zoología) para niños