The device used for leading and tying animals is called:

The correct answer is halter. A halter is specifically designed to be worn on livestock and is used for leading, tying, and controlling animals, particularly in agricultural settings. It typically consists of a strap that goes around the animal's head and includes a lead rope for the handler. Halters provide a secure method for handling animals without causing them discomfort, making them a preferred choice in managing livestock.

While a leash is often used with pets, particularly dogs, it is not appropriate for larger animals typically found in agricultural settings. Similarly, a collar, which is mostly used with pets, does not provide the control or security needed for leading and tying larger animals. A harness, on the other hand, is generally used for pulling or distributing weight rather than for leading or restraining an animal in the same manner a halter does. Thus, halters are the most suitable choice for leading and tying animals in the context of livestock management.