Did you ever wonder why mice shake with fright when they're near rats or cats? Well, it turns out there's a protein in the urine of rats and cats that makes mice flee. But when they smell the same protein produced by another mouse they often fight. Even naive mice who have never met a rat or a cat act as if they're terrorized by the odor. And, rabbit pee didn't have the same effect on mice, which wasn't a big surprise. From an evolutionary perspective this is a very neat story because it helps to explain why mice and other animals show fear to a wide variety of predators and enemies and don't have to discriminate among them. It's economical, if you will, to run when you detect a particular odor and not have to wonder if you should. Sure, a mouse can be wrong, but in the case of a predator or enemy who can harm or kill you, better safe than sorry. You might only get once chance and you better do what's best.
There also was an interesting report by the United Nations recently about who, not what, we eat. According to Professor Edgar Hertwich, the lead author of the report, "Animal products cause more damage than [producing] construction minerals such as sand or cement, plastics or metals. Biomass and crops for animals are as damaging as [burning] fossil fuels." According to the report, "Agriculture, particularly meat and dairy products, accounts for 70% of global freshwater consumption, 38% of the total land use and 19% of the world's greenhouse gas emissions..." The major problem is that there simply are too many of us now and the future population of earth is even more frightening. Professor Hertwich also cautioned "Developing countries should not follow our model. But it's up to us to develop the technologies in, say, renewable energy or irrigation methods."
And the war on wildlife continues. Wolves in Montana, Idaho, and Oregon are being killed because they're acting as wolves. They're slaughtered using inhumane methods. Why did we bring wolves back only to kill them after they've been successfully reintroduced? There are some serious ethical questions that need to be addressed. (see also) Wolves occasionally kill livestock and shouldn't be killed because they're doing what comes naturally.