First, there are way, way more scientists studying life on Earth than those searching for extraterrestrial life.
Ants work together not because of intelligence, but because they are genetically built to do so.
Intelligence is the ability to ask questions, to wonder about the existence of extraterrestrial life, to think philosophically. Dolphins don't do that. Gorillas can do simple addition, but they can't write proofs. They can find food when they are hungry, but they can't make the decision to not eat it because they want to lose weight. They are incapable. Ants all work together not because they know that if they don't work together they will die, but because an ant is physiologically incapable of doing something that will jeopardize their individual and group success. Success meaning surviving and procreating.
Humans are capable of asking the questions: Where did we come from? Why are we here? We are very curious, and we choose to make an effort to find the answers to those questions. Some people search for the answers in philosophy and religion. Animals don't have philosophy or religion. Some search for those answers by studying evolution and ecology on Earth. Some search for those answers by trying to explain the origins of the universe, by trying to figure out how life first comes into existence. Animals don't study science.
All animals do is act on the instincts that allowed their ancestors to survive over their competitors millions of year ago.