Animal Self-Defence

Animals live in a harsh world. Preying on other animals or being preyed by others is a common thing. So, they have adapted to these conditions, and they are now able to protect themselves. Some of them have horns. Bulls, buffalos, rhinoceroses, and other animals use their horns combined with technique. Adult musx oxen make a circle around the young oxen, so wolves won't be able to attack. Powerful jaws are also a weapon of choice for some animals, especially predators, such as the crocodiles. A stag beetle (Lucanus cervus, etc.) has oversized jaws that looks like a stag's antler.
Some animals play dead, emit a REALLY smelly odor, or do both in combination. When it senses danger, a ladybug will play dead and extract a liquid that smells real BAD. Possums also play dead when preyed.
That's only a few of how animals defend their lives. There are many more ways. Claws, quills, and even frightening poses and colours. There may be an animal that seemingly doesn't have any forms of defence, but somehow they are able to survive, whether by doing some sort of teamwork with other animals or by other ways.

image from www.junglewalk.com