The more we learn about the cognitive abilities of non-human animals, the more it becomes apparent that they have cognitive skills that resemble ours.
Differences in cognitive ability are differences in degree. We can think of animal intelligence as falling along a continuum, with human intelligence at the far end.
Crows can obtain food by using tools to obtain other tools, but they can’t build metal detectors.
Octopuses use tools as well—they build temporary hiding places out of halves of coconut shells. However, an octopus can’t build a castle or a fort (except, perhaps, metaphorically).
Dogs, bears, parrots and chickens seem to be able to count, but they can’t do calculus.
A bonobo can ask questions and create simple sentences using symbols on a touch screen, but he can’t write a novel.
In a Science News blog post, Tom Siegfried states that artificial intelligence research shows that the skills that distinguish humans from machines—such as the ability to identify objects quickly in order navigate through space easily and efficiently—are skills that we share with other animals.
Now, if you accept the fact of evolution, all of the above observations are easy to explain.
A common ancestor of two species could have had a cognitive skill (e.g. rudimentary language ability in an ancestor of the great apes) which later developed differently in the two species because of different survival needs in different environments.
Or similar cognitive skills could have developed independently in multiple species—a case of convergent evolution—if these skills aided the survival of all of these species.
In either case, animals became more intelligent because intelligence aided their survival.
Animals that hunt—or are hunted—must be able to negotiate obstacles and identify prey and predators quickly.
The ability to manufacture and use tools is a useful skill for any hunting or foraging species.