The term ‘fundamental’ has a specific meaning: that from which everything (or the greatest number of things) in a given context arises. Humans are definitely fundamentally different than other animals because we have a conceptual faculty and other animals do not. This conceptual faculty is absolutely fundamental to human beings.
Careful with your terms. Humans are not the only animals capable of forming concepts. Arguably, a great deal of animals are capable of forming concepts - being able to regard a group of entities as a single entity, as many animals have been proven capable of (off the top of my head, several species of birds, especially crows, dolphins, apes, et cetera), is a conceptual task. I’ll have to look for the paper on it, because the way they demonstrated this ability was actually quite clever. But besides that, many animals are capable of primitive use of tools, some monkeys have primitive systems of trade, and have even been taught to use currency. Simply associating sets of words with sets of actions, as many animals are capable of doing, is a conceptual task.
So no, we are not the only animals with a conceptual faculty, nor are we the only animals with a faculty of reason. Our faculty of reason is far and away better than any other animal’s of course, and this is a fundamental part of understanding human beings. But I would not argue that it makes us “fundamentally different” from other animals, because all naturally occurring parts of being human can also be found in other animals to greater or lesser degrees.