the capybaras defense system

My animal is the Capybara, they have a lot of predators like they have no defense mechanism when they are attacked they try their best to get to a source of water. Capybaras can hold their breath for around five minutes; this is their only way to not get attacked. So what I want to change about the capybara is the defense mechanism I want to give it spikes like a porcupine so it can defend itself the thing about the spikes is that they are barbed so the predators can't take them out but if the capybara for some reason does not release the spikes because it does not detect any sources of immediate danger they already can swim at a speed of 20 mph but the spikes will come in pretty handy when they are getting attacked by any bigger predator. What would you change about your animal?