There are some aspects of human behavior that separates humans from nonhuman animals. However, the issue depends on how we define intelligence. Nonhuman animals also have the capacity to make decisions, but based on what? Humans decide to choose to do something, whereas nonhumans decisions are made by their instincts, which means that the actions are predetermined.
Humans acquire language, but nonhumans learn it to some extent. -By language I mean human language, not nonhuman animal communication-
Let's look at this idea from a Darwinian perspective. He believed that human mind was a product of evolution. It does not matter for how long we have been living on this planet but we all have been living together in it for quite some time. What made our evolution faster than nonhumans so that we have a mind and they don't, looking from the perspective of Descartes? Are we here to learn and they to enjoy? -I choose to leave aside the ethical issues in this writing, it is an entirely different subject to discuss- Our brains have prefrontal cortex to make decisions and reason, so does mammals but not other animals.
So why don't they operate in the way that we do, why is there still a wide gap between our evolutionary state and theirs, because both human and nonhuman animals have intelligence that come from instincts?