Here are some characteristics of mammals:
* Give birth to live young: They don't lay eggs.
* Nurse their young with milk: They have mammary glands that produce milk to feed their babies.
* Have hair or fur: This helps them stay warm.
* Warm-blooded: They can regulate their own body temperature.
* Breathe air: They have lungs for breathing.
* Have a four-chambered heart: This allows them to transport oxygen efficiently.
These animals also share some other common characteristics:
* They are all vertebrates: This means they have a backbone.
* They are all relatively large: They are all bigger than most other animals.
* They are all strong and powerful: They have strong muscles and bones.
* They are all intelligent: They are capable of learning and problem-solving.
While it's important to acknowledge these fascinating characteristics, it's crucial to remember that keeping wild animals in captivity for entertainment, like in circuses, is often unethical and harmful.