It means the study of animal behavior. (We'll just guess that maybe not everyone knew that.) The word itself is from Greek, and ology means knowledge, and ethos means custom, or character. To put it simply, ethology studies how and why animals behave.
For instance, young animals often imprint, or attach to a surrogate mother after birth, on sight. A spider can build a web, though the spider's mother died before they even met. A perfect, complicated web. Some birds can reproduce entire songs of their species even if they haven't heard them, while other birds do not.
So how does this help us? It does, though not everything human do has to benefit us. This study of animal behavior, which can include instinct, can help potential problem situations. Many people know not to interfere with a mother and her cubs, and this applies to humans.
A better example is a freeze instinct. Yes, a loud sudden noise could indicate a dinosaur or other hunt-through-vision animal, and freeze might have saved an early ancestor of ours. Not so useful, however, when the loud sudden noise is a truck headed your way honking it's horn. The instinct to freeze is not useful then.
If the idea of helping animals is not making you and warm and fuzzy yet, there are many other examples of how ethology can help us. Special designed gates can lead animals where we wantsuch as in slaughter houses or on farms. Special fake owls can scare annoying birds, certain shapes on windows keep birds from hitting windows, the list goes on. A study of animal behavior, or ethology, can help us help animals.
An ethologist is a scientist, and studies the behavioral process among many animal groups and often studies a limited field of study in different animals. It is slightly different from animal behaviorist, who study learned behavior. Ethologist are usually zoologist.
Konrad Lorenz, Karl con Frisch, and Nikolaas Tinbergen are considered the fathers of ethology, though ethology has a history that reaches back to Darwin and beyond. The most common known ethologists Is Irenaaus Eibl-Eibesfeldt, who filmed humans with a hidden camera to compare gestures and body languages across cultures.
Of course, you might not grasp why we care if everyone in the world knows a smile is a smile. But it shows if you are a sci-fi writer, your aliens should probably will not recognize a smile; it is a human trait. Indeed many dogs and predators see a showing of teeth as threatening.
So do we care about ethologists and ethology? Oh yes. The study highlights human behavior as well as animal, it tells how to work better with nature, and high lights many human patterns, as well as sheds light on spacious topics like alien behavior. (Well sort of.) Ethology has had many benefits for humans, and will continue to improve our lives.