The image you sent me is a why does logo, so I will assume that you are asking why some animals have tails.

There are many reasons why some animals have tails. Some animals have tails to help them balance, while others have tails to protect them from predators. Here are some of the most common reasons why animals have tails:

• Balance: Tails can help animals balance, especially when they are running, jumping, or climbing. For example, cats and dogs use their tails to help them balance when they are walking on narrow surfaces or when they are jumping. Monkeys and other animals that climb trees use their tails to help them balance as they swing from branch to branch.
• Communication: Tails can also be used for communication. For example, dogs wag their tails when they are happy or excited. Some animals, such as rattlesnakes, have tails that they can rattle to warn predators away.
• Propelling: Some animals use their tails to propel themselves through the water. For example, fish use their tails to swim, and whales use their tails to move through the water.
• Attracting mates: In some animals, the tail is used to attract mates. For example, the male peacock has a long, colorful tail that he uses to attract females.
• Thermoregulation: Some animals use their tails to help them regulate their body temperature. For example, kangaroos use their tails to help them stay warm in cold weather.
• Defense: Some animals use their tails to defend themselves from predators. For example, lizards can use their tails to break off and distract predators.

In some cases, the exact reason why an animal has a tail is unknown. However, the reasons listed above are some of the most common reasons why animals have tails.